Creatures Big & Small

Katydid Asiophlugis species

2011-11-21T16:55:00.028+08:00

The intensive work on Orthoptera from the past one year has produced several new findings including some species that are new to science. These are either published already or in the process of being so.

Asiophlugis temasek

One of the new species is a little katydid, named Asiophlugis temasek after the old name for Singapore. This species measures only about 11mm in length and mostly found within our nature reserves. It is cryptic in behaviour, usually roaming on the underside of leaves. This tiny insect is quite charming. It is of emerald green with two large bulging eyes.

Including A. temasek, Singapore has three species from this genus. The other two is Asiophlugis rete and Asiophlugis thaumasia. The marvelous katydid mentioned in the Singapore Red Data book is actually A. thaumasia.

Asiophlugis thaumasia

Because they are so poorly studied, very little is known about their biology. Hence its always interesting to witness aspects of their behaviour. Recently we managed to shot a short video of an A. thaumasia performing a brief waltz dancing. Simply delightful

Actually what it is doing is generating motion parallax. The sideways head movements are means to judge distance and depth perception. In this instance, the head movements allow the little katydid to aim for an accurate targeted jump.

Asiophlugis species are predatory but its still uncertain how they actually hunt. Perhaps they can ambush prey with a mighty leap? It would be very fascinating to document.

Pictures and video taken at: Central Catchment Nature Reserve, December 2010; Bukit Timah Nature Reserve, November 2011

References:

Davison, G. W. H., P. K. L. Ng & H. C. Ho (eds), 2008. The Singapore Red Data Book: Threatened Plants and Animals of Singapore. 2nd Edition. The Nature Society (Singapore), Singapore

Gorochov, A. V. & M. K. Tan, 2011. New katydids of the genus Asiophlugis Gor. (Orthoptera: Tettigoniidae: Meconematinae) from Singapore and Malaysia. Russian Entomological Journal, 20(2): 129–133.

Kral, K., 2003. Behavioural–analytical studies of the role of head movements in depth perception in insects, birds and mammals. Behavioural Processes, 64:1-12.

Tan, M. K., 2011. The species of Asiophlugis Gorochov, 1998 in Singapore (Orthoptera: Tettigoniidae: Meconematinae). Nature In Singapore, 4: 233-239.

Neurobasis chinensis (Green Metalwing)

2011-07-20T11:38:00.016+08:00

Local extinction. These are the two words most dreaded by Singapore’s nature conservationists. It simply means an animal or plant which used to exist in Singapore no longer does and so a part of our natural heritage is lost. In local context, an animal is presumed nationally extinct if it has not been recorded for the last 50 years.

For odonates, we have lost a few species but perhaps the greatest lost of all is the brilliantly stunning damselfly, Neurobasis chinensis (Green Metalwing). This species belongs to a damselfly group that has amazed naturalists since it was first discovered sometime in the 18th century by scientists. It’s easy to see why. The gleaming flashes of metallic green wings as the males fly along a forest stream in their repertoire of territorial and courtship behavior is a sight to marvel. So much have these damselflies capture the wonder of naturalists that a book specifically dedicated to them was published four years ago.

I’ve seen Neurobasis chinensis in Peninsular Malaysia but not really been able to take clear photographs or videos till a recent trip to Langkawi. Males of Neurobasis genus will patrol and defend territories very vigorously at sunlight spots along streams . When displaying to each other, males will reduce the beats of their hindwings thus displaying the metallic iridescent green colour in its full glory under sunshine. In this way, males would chase each other along a stream in overlapping flights, wild chases, or tight spinning circles.
Sometimes a perched male may be challenged by an intruder. When this happens, the defending male will have his abdomen raised with the tip pointing down while the intruder hovers just in front. Both males will then flash the hindwings. The video shows this behaviour and we can see why these damselflies are so enthralling to observe.

N. chinensis is extensively distributed in South and Southest Asia. It is one of about 14 species in the genus. N. chinensis can inhabit a wide variety of habitat, from unspoiled mountain forest streams to slightly disturbed lowland sandy streams. Unfortunately it was last recorded from Singapore in 1970. The last known habitat within Macritchie reservoir’s streams was destroyed due to heavy siltation during the construction and subsequent expansion of the PIE. So it is now a 41 years gap of sighting. Technically the damselfly is not presumed nationally extinct till the dreaded number hit 50 years. But researchers have thus far failed to find the species and to the best of our knowledge, habitats suitable for N. chinensis to thrive no longer exist. Impoundments of rivers for reservoirs and heavy siltation from various constructions encroaching onto our nature reserves have taken their toll. But maybe, just maybe, someone might spot it one day before the 50 years is up.

We hope some resilient population of this damselfly, fittingly dubbed “Birds of Paradise amongst Odonata”, are still hanging on somewhere in Singapore.

Pictures and video taken at: Pulau Langkawi, July 2011

References:

Davison, G. W. H., P. K. L. Ng & H. C. Ho (eds), 2008. The Singapore Red Data Book: Threatened Plants and Animals of Singapore. 2nd Edition. The Nature Society (Singapore), Singapore

Murphy, D. H., 1997. Odonata biodiversity in the Nature Reserves of Singapore. In Proceedings of the Nature Reserves Survey Seminar. Gardens’ Bulletin Singapore. 49:333-352.

Orr, A. G. & M. Hämäläinen, 2007. The Metalwing Demoiselles (Neurobasis and Matronoides) of the Eastern Tropics: Their Identification and Biology. Natural History Publications, Borneo.

Tang, H. B., L. K. Wang & M. Hämäläinen, 2010. A Photographic Guide to the Dragonflies of Singapore. Raffles Museum of Biodiversity Research, Singapore.

Barred Kukri Snake, Striped Kukri Snake

2011-01-16T15:56:00.010+08:00

Snakes of the genus Oligodon are commonly known as Kukri snakes. They are so-named due to the curved hind fangs at the back of their mouth. Those fangs evolved to suit Kukri snakes’ diet of chiefly eggs. As the eggs are swallowed, they would be pierced open by the special fangs. The fangs’ shape reminds one of the famous Kukri knife used by Nepalese.

Singapore has three types of Kukri snakes: Brown Kukri (Oligodon purpurascens), Striped Kukri (Oligodon octolineatus) and Barred Kukri (Oligodon signatus).

Of the three, Striped Kukri snake is the most common and can inhabit suburban areas. Sometimes road kills are encountered, like this poor soul from 2006.

The other two species prefer forests in the nature reserves and thus rarer. Local books list them as ‘restricted to a few areas and rare’ and ‘critically endangered’. Perhaps of the two species, Barred Kukri snake is of more significance because Singapore is the type locality and knowledge on its biology is scarce.

So it was with great pleasure that a Barred Kukri snake was seen recently during a survey. The bright reddish-brown bands on its back are certainly attractive. And as the cameras clicked away, this elusive forest dweller slowly slipped back into the forest darkness. Thus ending a rare glimpse into another one of nature’s mysteries.

Pictures taken at: Eng Neo, June 2006; Central Catchment Nature Reserve, December 2010.

References:

Baker, N. & K. K. P. Lim, 2008. Wild Animals of Singapore. A Photographic Guide to Mammals, Reptiles, Amphibians and Freshwater Fishes, Draco Publishing and Distribution Pte Ltd, Singapore.

Davison, G. W. H., P. K. L. Ng & H. C. Ho (eds), 2008. The Singapore Red Data Book: Threatened Plants and Animals of Singapore. 2nd Edition. The Nature Society (Singapore), Singapore

Agrionoptera insignis , Agrionoptera sexlineata

2011-01-02T19:05:00.024+08:00

Different dragonflies species adopt different survival strategy during the vulnerable stage of metamorphosis and emergence from larva to adult. The majority of species leave the water either partly or completely before emergence. This behaviour is most likely meant to expose the thoracic spiracles to air respiration. But the amount of time a pharate adult (one that has changed from larva to adult but still within the old larval skin) spent outside of water before emergence varies. For most species, the time spent is usually on the day before emergence but some species have been known to stay out of water for up to 14-20 days. I’m not exactly sure the reasons behind this time variation and haven’t read up enough literature on this aspect of dragonflies biology. Thus recent emergence of two closely related species is interesting to note.

The first to emerge is Agrionoptera insignis (Grenadier). The larva was completely out of water for up to three days. During this time, it explored various spots on the driftwood, usually resting at a spot (blue arrows) for a few hours before moving on. In those three days, it seemed to be selecting an emergence spot meticulously. Either that or some parts of the larva was still undergoing changes to adulthood and so not yet ready for emergence.

Emergence into an adult female finally occurred on the fourth day.

Next up is a close relative from the same genus: Agrionoptera sexlineata (Handsome Grenadier). For this larva, the emergence was quick and straightforward. I spotted it out of water at early evening and by the next morning, the fine-looking adult male has emerged.

Its interesting how two similar and related larvae assumed different pre-emergence behaviour. But this is just a one-off observation and thus can’t constitute any concrete conclusion. Hopefully future larvae studies by other odonatologists can provide clearer understandings. The larvae emergence of both species is captured beautifully by Dr. Choong here:

http://odonata-malaysia.blogspot.com/2009/05/emerging-agrionoptera-insignis.html
http://odonata-malaysia.blogspot.com/2009/01/agrionoptera-sexlineata-larval.html

Agrionoptera insignis (Grenadier)

Agrionoptera sexlineata (Handsome Grenadier)

Although both A. insignis and A. sexlineata are listed as uncommon in the Singapore dragonfly book, the former is definitely more often encountered in the field and widely distributed while the latter species is more localised.

A. insignis female

A. sexlineata male

Pictures taken at: ex-situ, December 2010; Central Catchment Nature Reserve, August 2009 & December 2010.

References:

Corbet, P. S., 1999. Dragonflies: Behaviour and Ecology of Odonata. Cornell University Press, New York.

Tang, H. B., L. K. Wang & M. Hämäläinen, 2010. A Photographic Guide to the Dragonflies of Singapore. Raffles Museum of Biodiversity Research, Singapore.

Orthoptera

2010-12-13T14:20:00.078+08:00

Orthoptera (meaning ‘straight winged’) is an insect order which includes grasshoppers, crickets, katydids and relatives. This huge group makes up a significant biomass of terrestrial fauna. In the ecosystem they play a crucial herbivory role (although certain species are omnivorous or even carnivorous) as well as prey items for all sorts of predators from spiders to birds and lizards.

Conocephalus longipennis (female) feeding on grass seeds

Hexacentrus unicolor (nymph) feeding on an insect

Orthoptera is poorly studied in Singapore. The last person to do any significant work on them is Prof. Murphy 10-20 years back. Being less colourful and charismatic compared to other insects like butterflies or dragonflies, orthoptera has not attracted the attention of local nature enthusiasts. But not anymore as Tan Ming Kai, a young, mostly self trained orthopterist has started to make important progress in this field. When young, I used to catch small grasshoppers and rear them in small plastic tanks but mostly unsuccessfully. Now thanks to Ming Kai, I was able to look at them in a new light.

Around 100 species has been recorded in Singapore from surveys in the past months. Several species looks the same and so not easy to identify. It does takes lots of practices in the field before I can even identify the more common species. Some features like shape of the head, length of antennae and slight difference in body patterns can be diagnostic. Females usually have very long ovipositor at the rear end for egg-laying into the soil or plant materials.

Ducetia japonica

Eneropterinae (Gryllidae)

Tagasta marginella

Conocephalus melaenus (female)

Even though most species are uniformly green or brownish, there are some with really nice colours and patterns.

Traulia azureipennis

Xenacatantops humilis (nymph)

Nisitrus vittatus

Certain species are superb at camouflage, mainly trying to be like leaves. For example, Chondroderella borneensis will open its wings onto a leaf to flatten its profile thus becoming almost invisible. Simply amazing!

Systella rafflesii

Chondroderella borneensis

And as insects do, orthoptera go through a series of moult before reaching adulthood. Normally there are four to six nymph instars stages before adult. One way to recognise a nymph is their developing wings point downwards whereas adults’ wings point either upwards or backwards.

Conocephalus melaenus moulting

Among orthoptera, crickets and katydids are the most vocal. Their calls and songs serenade as one takes a night walk in the forest or grassland. The vocalisations are produced by means of stridulation where they rub their hind legs against the forewings or rubbing one wing against the other.

Mecopoda elongata

Local orthoptera research has been given a new lease of life by Ming Kai. There is already one scale cricket species described from Singapore by a foreign researcher but now a local guy studying local orthopteras are poised to describe other new species from here. This humble, largely ignored insect group is facing an exciting new dawn.

Larnaca species (Gryllacrididae)

Pictures and video taken at: Central Catchment Nature Reserve, September 2010, November 2010, December 2010 ; Dairy Farm, October 2010; Kranji Marshes, June 2010, August 2010.

References:

Ingrisch, S., 2006. New taxa and notes on some previously described species of scaly crickets from South East Asia. (Orthoptera, Grylloidea, Mogoplistidae, Mogoplistinae). Revue Suisse de Zoologie, 113(1): 133–227.

Tan, M. K., 2010. Orthoptera of the vacant lots in Bedok South. Nature in Singapore, 3: 69–81.

Tan, M. K., 2010. Orthoptera in Pulau Ubin. Nature in Singapore, 3: 245–268.

Singapore dragonflies & their African relatives

2010-08-30T16:59:00.038+08:00

Three months back, I was on work assignment in Nairobi Kenya for 13 days. Most of the work time was spent in the United Nations compound. Within the huge UN complex, many artificial but well vegetated ponds exist. It thus gave me the opportunity to explore African dragonflies. Although common species in Africa, they nevertheless filled me with joy and a sense of adventure upon seeing something new. I can now make a comparison on Singapore’s dragonflies and their relatives across the Indian Ocean.

Damselflies from the genus Pseudagrion come from a large widespread subfamily Pseudagioninae. We have four species here including a very rare one, Pseudagrion rubriceps (Orange-faced Sprite) which now seems to exist only at the pond in Toa Payoh Town Park.

I saw three relatives in Nairobi. One of them is Pseudagrion salisburyense (Salisbury Sprite) that has a range from interior South Africa to east, central and western Africa.

Pseudagrion massaicum (Masai Sprite) is an extremely beautiful damselfly. Males have red eyes, orangey thorax, green markings along the abdomen and blue abdomen tip. Surely one of the most colourful damselfly I’ve seen.

The last Pseudagrion species can’t be identified with certainty. Its either P. spernatum or P. kersteni.
Ceriagrion is another large genus but only two species are in Singapore. Ceriagion chaoi (Fiery Coraltail) in Singapore is very much like Ceriagrion glabrum (Common Citril) from Africa. Their colour scheme is very similar but C. chaoi has a brighter red abdomen and olive thorax.

Dragonflies of the genus Trithemis are from the subfamily Trithemistinae or commonly called Dropwings. There are more than 50 Trithemis species worldwide, and they are essentially African but five have made it to Asia. Singapore has three species. One example is Trithemis festiva (Indigo Dropwing). Here, this species is predominately stream loving and have adapted very well to large canals and storm drains.

In the UN compound, I observed four species, one more than the whole of Singapore. The four are: Trithemis arteriosa (Red-veined Dropwing), Trithemis cf. dorsalis (Dorsal Dropwing), Trithemis stictica (Jaunty Dropwing) and the prettiest of the lot Trithemis kirbyi (Kirby’s Dropwing).

The widespread genus Brachythemis is from the subfamily Sympetrinae. Singapore has one representative, Brachythemis contaminata (Common Amberwing). Wherever B. contaminata occurs, they are always in great numbers and have a habit of flying close to the ground especially the females and immature males.

In Africa, Brachythemis dragonflies are also known as Groundlings. One species from Nairobi is Brachythemis leucosticta (Banded Groundling). Males have banded wings while females have clear wings.

Probably the most common dragonfly genus in Singapore is Orthetrum (subfamily Libellulinae). We have five species, all of which can be easily seen. In Asia, some Orthetrum species have evolved reddish colour in mature males. However pruinosed blue in mature males is more common in the genus, for example our Orthetrum luzonicum (Slender Blue Skimmer).

African Orthetrum species are mostly pruinosed blue Skimmers thus making their identification much more difficult compared to in Singapore. I saw one species in Nairobi, Orthetrum julia (Julia Skimmer) where an immature male has greenish thoracic markings.

Aeshnids of the genus Anax are highly territorial. While in Nairobi, I spotted one big dragonfly speeding around a pond in a patrolling flight and immediately I knew it is an Anax. Very fortunately, it perched and I got a clear picture of this handsome Anax imperator (Blue Emperor). It is positively more colourful than Singapore’s Anax guttatus (Emperor). And a bonus, an ovipositing female was sighted the next day.

Aside from those highlighted here, I observed 15 species in total. It was great to see those African relatives. There’s much more to learn on dragonflies knowledge beyond Singapore. Furthermore through these sightings I got acquainted with Klaas-Douwe B. Dijkstra and Viola Clausnitzer. Both of them are experts in African dragonflies and very friendly in helping to confirm the species. Not forgetting Warwick and Michele Tarboton who generously sent me their guidebooks before I left for Kenya.

Hence local dragonfly lovers should take all opportunities to spot dragonflies beyond Singapore. Remember, there’s about 5700 species in the world!

Pictures taken at: Toa Payoh Town Park, January 2009; Venus Trail, September 2009; Nairobi Kenya, May 2010; Bishan Park, July 2010; Kranji Marsh, July 2010

References:

Silsby, J., 2001. Dragonflies of the World, CSIRO Publishing, Victoria, Australia.

Tarboton, W. R. & M. Tarboton, 2005. A Fieldguide to the Damselflies of South Africa. Privately published.

Tarboton, W. R. & M. Tarboton, 2009. South African Dragonflies. A Quick Guide. Graphic Touch Guides, South Africa

Longhorn Beetle (Xylorhiza adusta)

2010-06-27T19:08:00.012+08:00

I find longhorn beetles exceptionally charismatic. The long antennae (although some species have short antennae) easily distinguish this group from other beetles. And it is those long antennae, the large size of certain species including some really colouful patterned ones that have enthralled generations of naturalists. The Chinese has a very apt name for longhorn beetles: 天牛. It means ‘sky cow’. The long antennae reminding them of cow horns and ‘sky’, I can only, or would rather, assume refers to the beauty of these beetles that can only be heaven sent.

Longhorns are in the family Cerambycidae with about 35,000 described species worldwide. In larval stage they are mostly wood-borers and are thus considered pests in the forestry industry, especially so in western countries where introduced Asian species are considered invasive. But in their natural habitat, longhorns have an important role in the nutrient cycle in breaking down dying or decomposing woody plants. Most species can also feed on living trees. Adults feed mostly on young leaves and twigs.

Two recent species I saw. The first is Xylorhiza adusta from Sungei Buloh. It has a wide distribution in Asia, from India to China and down to Sumatra. Known host plants include Beautyberry trees (Callicarpa arborea and C. macrophylla); plant from the mint family (Premna pyramidata); Viburnum odoratissimum and Wrightia tinctoria: both a kind of small shrubby tree. All the above plants have not been recorded in Singapore but species from the same genus can be found here.

I still can’t identify the other longhorn except that its probably Acalolepta rusticatrix. I saw it, of all places, at a pedestrian bridge along Lornie Road.

Alfred Wallace was a beetle lover and collected 132 longhorn species from Singapore. His collections form the basis of our local knowledge and today Singapore has an estimated 220 plus species although a significant number might already be nationally extinct due to habitat loss. Current information on Singapore longhorn beetles diversity is still sketchy with many knowledge gaps to be filled. A giant step forward has been taken with this website (http://www.singaporeinsects.com/index.htm) created by the industrious Cheong Loong Fah.

Pictures taken at: Lornie Road, March 2010; Sungei Buloh Wetland Reserve, June 2010.

References:

Chong, K. Y., H. T. W. Tan & R. T. Corlett, 2009. A Checklist of the Total Vascular Plant Flora of Singapore: Native, Naturalised and Cultivated Species. Raffles Museum of Biodiversity Research, National University of Singapore, Singapore. 273 pp. Uploaded 12 November 2009. http://rmbr.nus.edu.sg/raffles_museum_pub/flora_of_singapore_tc.pdf.

Duffy, E. A. J., 1968. A Monograph of the Immature Stages of Oriental Timber Beetles (Cerambycidae). British Museum (Natural History), London.

Ek-Amnuay, P., 2008. Beetles of Thailand. 2nd Edition. Amarin Printing and Publishing Public Co., Ltd, Bangkok.

Pseudagrion microcephalum; Ceriagrion cerinorubellum; Ischnura senegalensis; Pseudagrion australasiae; Podolestes orientalis; Euphaea sp.

2010-04-18T23:57:00.041+08:00

It is easy to recognise the larvae of damselflies. Compared to a typical dragonfly larva they are slimmer and less robust. More notably, damselfly larvae have three very distinctive caudal lamellae, also called external or larval gills, at the end of the abdomen. These are absent in dragonfly larvae.

The caudal lamellae have a variety of functions. They aid in respiration, function as fins during motion and can even break off in times of escape much akin to the discarded tail of a fleeing gecko. And just like a gecko’s tail, a larva can grow back its lost lamellae. The lamellae aid, but are not essential in respiration. Thus it is not unusual to see larvae missing one, two or even all of its lamellae just like the larva of Pseudagrion microcephalum below.
The shape and size of caudal lamellae will change as a larva grows. In many species, the lamellae will become smaller relative to abdomen length but expanding in width and more tracheated, hence having a bigger role in respiration.

Size, length, shape and patterns of caudal lamellae are essential tools in identifying species. Most damselfly larvae have lamellae which are flat and vertical like those of Ceriagrion cerinorubellum, Ischnura senegalensis and Pseudagrion australasiae. The brownish spots on the lamellae of C. cerinorubellum are examples of patterns which can occur.

Meanwhile, damselflies of the Euphaea species have their caudal lamellae in the form of swollen saccoids with a terminal filament.

Recently larva of the damselfly Podolestes orientalis is described. The species is from the family Megapodagrionidae and members from this family have their caudal lamellae in a horizontal plane. This character is unique to the family although not all species in the family have horizontal lamellae. I find the fan-like shape and banded patterns of P.orientalis lamellae very eye-catching. The larvae are now known to inhabit submerged leaf litter at the edge of shallow pools where they raised their abdomen upwards and have their lamellae splayed near the water surface. In this way, horizontal lamellae may be better adapted to aid respiration near the water surface in an otherwise low oxygen leaf litter forest pool. P. orientalis is a rather common species in our forests.

The larvae of many odonate species remain unknown and undescribed. Further discoveries will help scientists shed more light on the evolutionary history of this wonderful insect group.

Pictures taken at: Ex-situ, June 2009; September 2009; October 2009

References:

Choong, C. Y. & A. G. Orr, 2010, ‘The larva of Podolestes orientalis from West Malaysia, with notes on its habitat and biology (Odonata: Megapodagrionidae)’, International Journal of Odonatology, vol. 13(1), pp. 109-117.

Corbet, P. S. & S. J. Brooks, 2008. Dragonflies. HarperCollins Publishers, London, UK.

Kalkman, V. J., C. Y. Choong, A. G. Orr & K. Shutte, 2010, ‘Remarks on the taxonomy of Megapodagrionidae with emphasis on the larval gills (Odonata)’, International Journal of Odonatology, vol. 13(1), pp. 119-135.

Orr, A. G., 2005. Dragonflies of Peninsular Malaysia and Singapore, Natural History Publications (Borneo) Sdn. Bhd, Malaysia

Brahminy Blind Snake

2010-02-07T20:15:00.009+08:00

Nature never fails to astound me. It is not always necessary to venture into forests to see some of the most amazing creatures, they can be right here in our backyard.
A gardening session by a colleague unearthed this incredible Brahminy Blind Snake (Ramphotyphlops braminus). This is one of the smallest snakes in the world, with a total length averaging about 13cm only. It is easily mistaken for an earthworm but trained naturalists will be able to tell it doesn’t have a segmented body. Instead the body is smooth, cylindrical and on closer examination, the presence of scales. And it is much more active than an earthworm is.

Apparently it is not blind but has tiny eyes. Eyesight is not of utmost importance since this snake spends its time burrowing in the dim world of root masses and soil, hunting small insects especially ants and termites. I tried to see the eyes under a microscope. It’s a thrill to see two black minute eyes staring back.

Another amazing aspect is this species is parthenogenetic, meaning females reproducing females asexually without fertilisation of eggs by males. In fact the Brahminy Blind Snake is an all female species. This is a common reproductive strategy in insects but not so in vertebrates. Some fishes, amphibians and of course snakes are known to be parthenogenetic.

This snake is said to originate from Sri Lanka or southern India, but is now very common in most regions including Singapore thanks to our horticultural practices. Though common and widespread, its ecology hides it away from humans most of the time making this wonderfully intriguing creature a hardly seen rarity…..…unless we start digging through all garden plots.
So if you are an avid gardener, do be gentle when encountering this snake. It is harmless, can be handled safely and is deserving of a home in our gardens.

Pictures taken at: National Biodiversity Centre, December 2009.

References:

Baker, N. & K. K. P. Lim, 2008. Wild Animals of Singapore. A Photographic Guide to Mammals, Reptiles, Amphibians and Freshwater Fishes, Draco Publishing and Distribution Pte Ltd, Singapore.

Wallach, V., 2008, ‘Range extensions and new island records for Ramphotyphlops braminus (Serpentes: Typhlopidae)’, Bulletin of the Chicago Herpetological Society

, vol. 43(5), pp. 80-82.

Tetracanthagyna larva

2010-01-17T17:53:00.024+08:00

An impressive larva I’m currently rearing has provided very fascinating insights into terrestrialism in dragonflies larvae.
This aspect of larvae ecology is rather well known. There are several studies showing larvae inhabiting small streams or seepages in forest can have a diminished dependence on water. Some species in Japan live among wet rock and mosses beside streams, a species in Himalaya hang around wet ferns near waterfalls and one species from New Caledonia clings onto the underside of moist leaves away from any water body.

Closer to home, larvae of the genus Tetracanthagyna exhibits semi-terrestrial behaviour. Tetracanthagyna degorsi from Borneo apparently leaves the water at night to perch head down near water surface, seemingly to catch surface swimming fishes. T. waterhousei is another species with similar habits. There’s a picture of its larva catching a fish while completely out of water in the Field Guide to Dragonflies of Hong Kong 2nd edition (page 211).

The larva I have now also shows identical behaviour. Its hunting strategy is ambush. Most of the time it clings out of water with only the head partially submerged. From this position it waits, and when a shrimp moves near, wham! The forceful impact of its labium capturing the hapless shrimp fatally.
After capturing, the larva will occasionally move completely out of water to consume the prey. I notice the bigger the shrimp, the more likely it’ll move above water for consumption. And this becomes more frequent as the larva grows.
Those with a phobia for things creepy and crawly will find this larva utterly hideous. It is now almost entirely black, having adapted its colour to the surroundings; it currently measures about 6cm in length; and has a dragon-like frontal appearance. It might look monstrous but once emerged into adult, it will become the biggest dragonfly in the world in terms of wingspan and weight.

Tetracanthagyna plagiata is the only species from the genus recorded in Singapore so this larva should be of the species. I didn’t have the chance to establish its gender accurately so hopefully it’ll emerge into a male as very few male specimens of T. plagiata exists in museums worldwide. It should emerge very soon as it has stopped feeding for the past few days.

Pictures taken at: ex-situ, November, December 2009 & January 2010.

References:

Corbet, P. S., 1999. Dragonflies: Behaviour and Ecology of Odonata. Cornell University Press, New York.

Norma-Rashid, Y., L. F. Cheong, H. K. Lua & D. H. Murphy, 2008. The dragonflies (Odonata) of Singapore: Current status records and collections of the Raffles Museum of Biodiversity Research. Raffles Museum of Biodiversity Research, Singapore. 24 pp. Uploaded 07 Nov 2008 [http://rmbr.nus.edu.sg/raffles_museum_pub/Dragonfly_of_Singapore.pdf]

Orr, A. G., 2003. A Guide to the Dragonflies of Borneo. Their Identification and Biology. Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Orr, A. G., 2005. Dragonflies of Peninsular Malaysia and Singapore. Natural History Publications (Borneo) Sdn. Bhd, Malaysia

Wilson, K. D. P., 2004. Field Guide to the Dragonflies of Hong Kong 2nd edn. Agriculture, Fisheries and Conservation Department, Hong Kong SAR.

Kopstein’s Bronzeback (Dendrelaphis kopsteini )

2009-12-01T20:40:00.010+08:00

A recent survey at the Central Catchment turns out to be one of the best I’ve had this year. Rare creatures sighted, good weather and good companions made a perfect morning in the forest. We spotted three snakes that day. The stand out has to be this Kopstein’s Bronzeback (Dendrelaphis kopsteini).
Also known as Red-necked Bronzeback, this species has always been confused with Elegant Bronzeback (Dendrelaphis formosus). It was only in 2007 that scientists sorted out the taxonomy and designated it as a separate species. We now know Kopstein’s Bronzeback can be distinguished from other Bronzeback snakes by its bright orangey red colour at the back of its neck. The species is widespread locally, being also present in rural or suburban areas. Although widespread, it is considered rare by Baker & Lim (2008) and has a status of vulnerable in the Red Data Book. Its distribution is from Thailand down to Peninsular Malaysia and Sumatra.

We were very lucky indeed to chance upon this individual consuming a lizard. When we first saw it, it had already captured the prey. After a brief struggle, the snake proceeded with lunch, swallowing the lizard in a matter of minutes. Our presence did not bother it at all thus enabling me to get a close video. Spotting creatures in the wild is always great but a window into the midst of their daily activity is unquestionably a huge bonus.

Kopstein’s Bronzeback is named after the Austrian herpetologist Dr. Felix Kopstein (1893-1939).

Pictures and video taken at: Central Catchment Nature Reserve, November 2009.

References:

Baker, N. & K. K. P. Lim, 2008. Wild Animals of Singapore. A Photographic Guide to Mammals, Reptiles, Amphibians and Freshwater Fishes, Draco Publishing and Distribution Pte Ltd, Singapore.

Davison, G. W. H., P. K. L. Ng & H. C. Ho (eds), 2008. The Singapore Red Data Book: Threatened Plants and Animals of Singapore. 2nd Edition. The Nature Society (Singapore), Singapore.

Vogel, G. & J. Van Rooijen, 2007. ‘A new species of Dendrelaphis (Serpentes: Colubridae) from Southeast Asia’, Zootaxa 1394: 25–45.

Neurothemis fluctuans; Trithemis aurora

2009-11-08T23:11:00.024+08:00

How do dragonflies recognise members of their own species? Recognition of conspecifc is primarily through visual cues for dragonflies. They can recognise flight style, size, colours and patterns as well as ultraviolet reflection and optical density. The ability to recognise their own species is important as it enables dragonflies to defend territory and for a male to find the right female.

But sometimes, mistakes do occur. On a recent sunny morning in Singapore Botanic Gardens, a whole lot of dragonflies were active. There was about six species present and the area was buzzing. It seemed like an orgy was taking place as males grasped females for copulation and inseminated females were ovipositing. The males were also fighting each other for the females. Suddenly a tandem pair crashed onto a plant. A male Neurothemis fluctuans had grasped a female Trithemis aurora. The pair made several attempts to fly off but failed.

Tandem link between different dragonflies species is prevented because of the incompatibility between a male’s anal appendages and a different female’s head. It is like a lock and key system; the right key must fit the right lock. In this case, it is obvious the male N. fluctuans couldn’t grasp the female properly. After several tries, the male realised its mistake and released the female.
Both Neurothemis fluctuans and Trithemis aurora are very common species here. Both species are sexually dimorphic. Mature N. fluctuans males are reddish while the females are light brownish. For T. aurora, mature males are pink while females are yellowish.

Pictures taken at: Singapore Botanic Gardens, 2009; Toa Payoh Town Park, 2009 & 2008.

References:

Corbet, P. S. & S. J. Brooks, 2008. Dragonflies. HarperCollins Publishers, London, UK.

Brown Tree Snail

2009-08-30T17:40:00.011+08:00

Recently, the rarest land snail in Singapore was sighted in great numbers. They were all congregated on two trees in the Singapore Botanical Gardens (SBG), several of them mating with some observed among leaf litter. This is the Brown Tree Snail (Amphidromus inversus inversus).

This critically endangered snail is mainly arboreal, inhabiting trees within primary forests preferring humid and damp conditions. Only one population survives in Singapore, and that's in SBG. We are not sure how big the population is but I believe it is hanging on by a thread considering the snail is found only within a small area in SBG. My knowledge on land snails are limited so I wonder why its found only at SBG and not in our forest reserves too. As mentioned in the Singapore Red Data Book, a study on population size is long overdue and a concerted effort must be made to introduce a second population in the nature reserves.

We have five Amphidromus species and subspecies in Singapore. The other one that is also rare is the Green Tree Snail (Amphidromus atricallosus perakensis) from the nature reserves.
As I took the pictures, passerby walked past. Some gave me curious glances but most ignored me. Many Singaporeans don’t know we have several species of flora and fauna eking out a last stand here. Many of these species are unspectacular and inconspicuous unlike the charismatic Colugo or the iconic Oriental Pied Hornbills. The extinction of a snail would hardly make a dent in an urban dweller’s life. But it’ll be a loud silent scream from our natural heritage.

Snails in the pictures are individually marked for research purposes.

Pictures taken at: Singapore Botanical Gardens, August 2009.

References:

Lok, A. F. S. L. & S. K. Tan, 2008, ‘A review of the Singapore status of the Green Tree Snail, Amphidromus atricallosus perakensis Fulton, 1901 and its biology’, Nature In Singapore, vol. 1, pp. 225-230.

Davison, G. W. H., P. K. L. Ng & H. C. Ho (eds), 2008. The Singapore Red Data Book: Threatened Plants and Animals of Singapore. 2nd Edition. The Nature Society (Singapore), Singapore.

Orthetrum chrysis ; Larva Emergence

2009-06-13T16:41:00.036+08:00

Although dragonfly larvae have been studied widely, this aspect of their life history still harbours unsolved mysteries. For example, there’s several dragonfly genus whose larvae are still unknown and not found or described. The best way to study larvae ecology is to rear them ex-situ. This requires patience, time and acquired knowledge through practice. Inspired by the excellent work by Dr. Ian Choong from Malaysia and encouragement from Yeh Wen-Chi in Taiwan, I decided to take on this challenge whole heartedly.

Two to three days prior to emergence, a typical larva will stop feeding and climb partially out of the water. This is when aquatic respiration slowly change into atmospheric respiration. Once ready it will leave the watery environment into an aerial existence. After rearing this larva for 20 days, a miracle of nature finally unfolded.
Tropical dragonflies mostly emerge at night to pre-dawn. There are four stages of emergence. The first is when the larva search for a suitable support, climbing upwards and away from water. At this stage, the cuticle is still intact.

At second stage. the cuticle of the head and thorax split with the adult now pushing itself out of the moult (known as exuvia in dragonflies). Looking at the process, I actually sensed the dragonfly’s physical exertion. Slowly, the head, thorax and legs emerged with only the abdomen still inside the exuvia. Normally, a dragonfly would then rest for a while.
When it has regained energy, it swung forward to hang onto the exuvia and pulled its abdomen out. This is the third stage. The dragonfly is now fully emerged but looks all wriggled and fragile.

Finally in stage four, bodily fluids are pumped throughout the body to expand the abdomen and wings and also gaining full colour. Just like an ugly duckling, its wings open and transformed into a beautiful reddish female Orthetrum chrysis.
The entire four stages require 1-2 hours. Sacrificing sleep from 4-6am to witness this event is certainly worth it. For a dragonfly, it now enters an aerial lifestyle of hunting, territorial fights and procreating the next generation.

Orthetrum chrysis is a common dragonfly. Although mostly encountered at forest margins, we can also find them in well-vegetated park ponds. Of the several red-coloured dragonflies in Singapore, males of O. chrysis can be recognised by its red abdomen and blackish-brown thorax.

Pictures taken at: ex-situ, May 2009 (larva and emergence); Bishan Park pond, September 2008 (adult male).

References:

Corbet, P. S. & S. J. Brooks, 2008. Dragonflies. HarperCollins Publishers, London, UK.

Silsby, J., 2001. Dragonflies of the World, CSIRO Publishing, Victoria, Australia.

Anax guttatus (Hairy Emperor); Aeshnid Larva

2009-05-03T14:18:00.021+08:00

I reckon the most impressive of Singapore’s dragonflies are from the family Aeshnidae. There’s about 400 species worldwide. They are characteristically robust in built; are fast strong fliers making huge sweeps around their habitat; and several species are crepuscular. Nine aeshnid species have been recorded in Singapore. Anax guttatus (Hairy Emperor) is the most common as it can be found in open habitats of big ponds or lakes. Species of the genus Anax are well-known for their territoriality. In many ponds here, it is rather easy to encounter a huge dragonfly patrolling a pond by flying along the pond margin with great speed and purpose. Chances are it is the Hairy Emperor, appropriately named by the way it seems to lord over a pond.

Aeshnids are unlike most other dragonflies in that females will insert their eggs into plant tissue. This ovipositing mode is the same as damselflies. Aeshnid females have well-developed ovipositors to cut minute slits into plant tissue for egg insertion. This behaviour is seldom seen so I was very fortunate to witness an Anax guttatus with colleagues recently. The videos show a female ovipositing into the floating plant stem. A. guttatus, when not flying at speed, is quite easy to recognise with its overall greenish colour and blue pattern on the abdomen. Up close, it is a beautiful and impressive dragonfly.

The larvae are another fascinating aspect of these insects. Depending on their behaviour and microhabitats, anisopteran larvae are typically recognised into four broad categories: claspers; sprawlers; hiders; and burrowers. Aeshinids larvae are generally claspers as they cling onto submerged vegetation or twigs. They are elongated with large prominent compound eyes. The shape and position of those eyes can be used to identify aeshnids larvae to genus. Anax species larvae have large forward facing oval-shaped eyes. They are very aggressive, excellent hunters. Apparently they can also change their colouration with each successive moult to suit their surroundings for better camouflage. I think this emerald green Anax larva is particularly eye-catching.

The labium is unique to odonates. It is basically an extensible organ with hook and pincers to ensnare prey. It is like an energy storage mechanism which can be released with speedy accuracy. Sight and labium co-ordination required by a larva to capture prey is undoubtedly precision of the highest order.

Pictures and videos taken at: Bukit Timah Nature Reserve, April 2009 (Anax guttatus); ex-situ, April 2009 (Anax larva).

References:

Corbet, P. S. & S. J. Brooks, 2008. Dragonflies. Harper Collins Publishers, London, UK.

Norma-Rashid, Y., L. F. Cheong, H. K. Lua & D. H. Murphy, 2008. The dragonflies (Odonata) of Singapore: Current status records and collections of the Raffles Museum of Biodiversity Research. Raffles Museum of Biodiversity Research, Singapore. 24 pp. Uploaded 07 Nov 2008 [http://rmbr.nus.edu.sg/raffles_museum_pub/Dragonfly_of_Singapore.pdf]

Orr, A. G., 2003. A Guide to the Dragonflies of Borneo. Their Identification and Biology, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Orr, A. G., 2005. Dragonflies of Peninsular Malaysia and Singapore, Natural History Publications (Borneo) Sdn. Bhd, Malaysia

Raphismia bispina (Bispina Skimmer)

2009-03-20T22:50:00.021+08:00

Thanks to Ria and the Semakau Book team, we had a chance to explore the back mangroves of Semakau a few weeks back. Because of the mangrove’s general good health, I was expecting to find the mangrove specialist Raphismia bispina (Bispina Skimmer). Thus it was a delight to finally spot two blue males flying within a sunlight spot among the prop roots.

This dragonfly is one of two or three species in Singapore that have adapted to back mangrove habitats. It is an inconspicuous dragonfly where males usually perch for long periods defending their territories. Although widespread throughout Sundaland, it breeds only in salty water of back mangroves. It is therefore highly specialised and rather rare. In Singapore, R. bispina is classified as uncommon and has been recorded from only a handful locations.

Two features are used to distinguish this species from others. Raphismia bispina has two downward pointing spines behind the hind legs at the rear of the synthorax. It also has two bifid process projecting from beneath abdominal segment S2. It’s difficult to see these tiny features unless there’s a close-up photograph.

We were lucky to observe a female while on the way out. She has mottled yellowish patterns on the thorax and yellowish streaks running down her abdomen. Like the male, she perched patiently on a branch and we could see that she’s gleaning for prey. She awarded us with good close-up shots and her vulva scale beneath the abdomen tip was visible. This ‘spout’ like structure is where eggs leave the females during ovipositing. Vulva scale is not found in those dragonflies that oviposit into plant tissues.

Mr. Joe Pan from Sabah also had a recent wonderful encounter with this mangrove specialist. In Borneo, R. bispina is known only from the extreme northern tip and Brunei.

Dragonflies larvae are typically hyperosmotic regulators in fresh to moderately saline waters. According to Corbet (1999) most species adapted to brackish habitats generally occur in waters not exceeding 8.6% of the salinity of seawater. It will be interesting to investigate if this is also true for R. bispina.

Pictures taken at: Pulau Semakau, February 2009

References:

Corbet, P. S., 1999. Dragonflies: Behaviour and Ecology of Odonata. Cornell University Press, New York.

Dijkstra, K-D. B. & R. Lewington, 2006. Field Guide to the Dragonflies of Britain and Europe, British Wildlife Publishing, United Kingdom

Norma-Rashid, Y., L. F. Cheong, H. K. Lua & D. H. Murphy, 2008. The dragonflies (Odonata) of Singapore: Current status records and collections of the Raffles Museum of Biodiversity Research. Raffles Museum of Biodiversity Research, Singapore. 24 pp. Uploaded 07 Nov 2008 [http://rmbr.nus.edu.sg/raffles_museum_pub/Dragonfly_of_Singapore.pdf]

Orr, A. G., 2003. A Guide to the Dragonflies of Borneo. Their Identification and Biology, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Orr, A. G., 2005. Dragonflies of Peninsular Malaysia and Singapore, Natural History Publications (Borneo) Sdn. Bhd, Malaysia

Banded Phintella

2009-03-06T01:27:00.014+08:00

Jumping Spiders are one of the most efficient hunters of insects. They have superb abilities to spring onto prey with precise accuracy. This precision is mostly thanks to their keen eyesight. The eyes arrangement is such that they have an almost 360° field of vision. Two huge front eyes give jumping spiders a telephoto-like system while eyes at the sides are akin to stereoscopic wide-angle lenses. A Banded Phintella (Phintella vittata) shows very clearly the ever vigilant eyes ready to process an all-round image, directing the spider to make the next precise jump.

I love the slight golden tinge on its carapace and abdomen. A closer look reveals a streak of blue on the femur. This makes the spider even more attractive. Using innovative experiments, local researchers have shown that females of another jumping spider species (Cosmophasis umbratica) would spend a longer time observing ultra-violet (UV+) males than UV- males regardless of which male display more actively. This suggests for that species, male UV influence plays a role in female-mate choice. Perhaps similarly, the iridescent bluish leg femora would help a male Banded Phintella in attracting the opposite sex.

Banded Phintella can be encountered at gardens as well as forested habitats.

Pictures taken at: Central Catchment Nature Reserves, February 2009

References:

Koh, K. H. J., 1989. A Guide to Common Singapore Spiders. Singapore Science Centre, Singapore.

Lim, M. L. M., J. Li & D. Li, 2008. ‘Effect of UV-reflecting markings on female mate-choice decisions in Cosmophasis umbratica, a jumping spider from Singapore’, Behavioral Ecology, vol. 19 (1), pp. 61-66.

Libellago aurantiaca (Red Jewel)

2009-01-18T20:42:00.015+08:00

In the streams of our nature reserves lives a damselfly affectionately known as Red Jewel. This is because the males are dazzlingly colourful and in bright sunshine, the metallic reflective patches on their wings sparkle as they fly along a flowing stream.

Jewels are from the family Chlorocyphidae which consists of about 140 species worldwide, most of them distributed in Asia, Africa and Australasia. These damselflies, with the exception of the genus Rhinoneura, have their abdomen shorter than their hindwings thus separating them from other damselfly species. Another characteristic feature is the presence of an upturn snout which I feel gives them a rather cartoon-ish appearance.

Singapore has two Jewels species: the red abdomen Libellago aurantiaca and the rarer violet abdomen Libellago hyaline (Hyaline Jewel).

Red Jewels inhabit and breeds in clear swift flowing forest streams. Males are more commonly seen perching on logs or leaves on or near the water. They are highly territorial and disputes between males are settled by the most elegant way. In bright sunshine, males would confront one another hovering at almost the same spot. Facing each other but never coming into contact, these bouts of territorial displays can last for hours or as long as sunshine penetrates the forest canopy. The tangos are always conducted at sunlit spots, presumably to best showcase their striking colours.

Among Singapore’s damselfies, Jewels are perhaps most susceptible to habitat degradations. They require unpolluted swift streams for breeding and with a sedentary lifestyle, are not known to travel far from where they breed. Populations can therefore become isolated easily and some streams in our reserves have already lost their Red Jewels when the streams’ natural flow is altered by human impacts.

Conserve our fragile forest ecosystem and we’ll protect the forest’s Jewels.

Pictures and videos taken at: Central Catchment Nature Reserves, November 2008

References:

Norma-Rashid, Y., L. F. Cheong, H. K. Lua & D. H. Murphy, 2008. The dragonflies (Odonata) of Singapore: Current status records and collections of the Raffles Museum of Biodiversity Research. Raffles Museum of Biodiversity Research, Singapore. 24 pp. Uploaded 07 Nov 2008 [http://rmbr.nus.edu.sg/raffles_museum_pub/Dragonfly_of_Singapore.pdf]

Orr, A. G., 2003. A Guide to the Dragonflies of Borneo. Their Identification and Biology, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Orr, A. G., 2005. Dragonflies of Peninsular Malaysia and Singapore, Natural History Publications (Borneo) Sdn. Bhd, Malaysia

Silsby, J., 2001. Dragonflies of the World, CSIRO Publishing, Victoria, Australia.

Devadatta argyoides

2008-11-15T03:46:00.029+08:00

Competition to find a mate and reproduce the next generation is always very intense in the animal kingdom. Sometimes even a successful mating might not necessary guarantee the offsprings are sired by the original male.

Males of dragonflies and damselflies are especially adapted to displace the sperm of the previous male from a female. The discovery of sperm displacement in odonates by Prof. Jonathan Waage in 1979 is considered a significant finding in odonatology. Since then, it is now known there are four distinct ways a male can displace a rival male’s sperm: 1) physical removal by means of hooks or horns on the penis; 2) moving rivals’ sperm to sites in the females where its least likely to be used; 3) stimulation of female to induce sperm expulsion; 4) flushing out of rival’s sperm using the copulating male’s sperm.

These are fascinating behaviours. An earlier post mentioned this casually. Recently, I observed the copulation of Devadatta argyoides, enabling me a better understanding of sperm displacement.

Devadatta argyoides is from the family Amphipterygidae. This is a small and primitive family with only one species present in Peninsular Malaysia and Singapore. In fact Singapore is the type locality for this damselfly. It is rather common and usually found perching near small forest streams.

This couple had just gotten into tandem when I first spotted them. The male then flew with the female in tow for a short distance before perching above the stream. Slowly the female bent her abdomen to form the 'wheel’ thus interlocking their genitalia. Almost immediately, the male started displacing rivals’ sperm. This can be seen clearly by the male abdomen’s active movement. It lasted for about 2-3 minutes before the male stopped moving to transfer in his own sperm.

After copulation, the couple separated with the female flying off a distance away. The male did not seem interested in mate guarding nor did the female oviposit after I followed her for almost 10 minutes. I’m not familiar with the mating system of D. argyoides. Perhaps during this post-copulatory rest, the female was assessing the male’s guarding capacity, or the suitability of ovipositing site, or she’s manipulating the recently received sperm for fertilisation and evaluating its quality. The mating systems in odonates are varied with six systems currently recognised by scientists. There are lots more to discover on odonates mating behaviour especially species rarely encountered due to their elusive nature.

Pictures and video taken at: Bukit Timah Nature Reserve, October & November 2008

References:

Corbet, P. S. & S. J. Brooks, 2008. Dragonflies, HarperCollins Publishers, London, UK.

Lieftinck, M. A., 1954. ‘Handlist of Malaysian Odonata’, Treubia, vol 22, pp. 1-202.

Orr, A. G., 2003. A Guide to the Dragonflies of Borneo. Their Identification and Biology, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Orr, A. G., 2005. Dragonflies of Peninsular Malaysia and Singapore, Natural History Publications (Borneo) Sdn. Bhd, Malaysia

Vestalis amoena; Vestalis amethystina

2008-11-09T15:49:00.028+08:00

Vestalis amoena

Among Singapore’s damselflies, species from the genus Vestalis probably have the most attractive wings. Depending on the viewing angle and reflecting sunlight, the clear wings of these damselflies can appear to sparkle with purplish iridescence. We have two species in Singapore, Vestalis amoena and Vestalis amethystina. Both species look very much alike with the same metallic green colouration. In fact, the nine species known to exist in Sundaland are so similar in appearance that even differences in wings venation, body colouration and male penis structure are too ambiguous for species recognition. The only sure way to distinguish the species is by examining the male’s anal appendages.

Vestalis amethystina

Although it seems difficult but with a good digital camera giving a close-up shot of the male’s anal appendages, it is actually rather easy to identify our two Vestalis species in the field without having to capture them. For Vestalis amoena, the appendages are less curved towards each other and appear shaped like a horseshoe.

On the other hand, Vestalis amethystina has their appendages more curved towards each other. Females can be separated by the yellow labium of V. amoena and black labium of V. amethystina.

The geographical distribution of these two species is interesting. Both of them occur together from southern Thailand, Malay Peninsula to Sumatra. But V. amoena extends into Borneo while V. amethystina does not. In Borneo a close relative V. amaryllis, not found in the Malay Peninsula or Sumatra, exists. So it seems V. amaryllis became isolated in Borneo, differentiate into an independent species and occupies an ecological niche before V. amethystina could establish itself.

In Singapore, both V. amoena and V. amethystina occupy similar habitat: flowing streams in dense forest vegetation. However V. amoena is reportedly less common than V. amethystina. This seems to be very true as I encounter V. amoena less often during regular trips into the nature reserves. One very possible reason is that V. amoena prefers larger and faster flowing streams.
As forests degradation occurs, silt and sediments become accumulated causing streams to flow slower thus making it a more suitable habitat for V. amethystina. Historical records show that V. amoena was once found in Ulu Pandan. This is a perfect case in point of how much forests we have lost and how vulnerable forest damselflies are.

Pictures taken at: Central Catchment Nature Reserve, June 2008.

References:

Laidlaw, F. F., 1931. ‘A list of the dragonflies (Odonata) of the Malay Peninsula with descriptions of new species’, Journal of the Federated Malay States Museums, Singapore, vol 16, pp. 175-233.

Lieftinck, M A., 1965. ‘The species-group of Vestalis amoena Selys, 1853, in Sundaland (Odonata, Calopterygidae)’, Tijdschrift voor Entomologie, vol 108, pp. 325-364.

Orr, A. G., 2003. A Guide to the Dragonflies of Borneo. Their Identification and Biology, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Orr, A. G., 2005. Dragonflies of Peninsular Malaysia and Singapore, Natural History Publications (Borneo) Sdn. Bhd, Malaysia

Asian Toad

2008-10-01T13:09:00.010+08:00

Singapore has about 24 native species of frogs and toads. The common species are of course very adapted to human landscape. They are more often heard than seen, especially after a period of heaving rainfall when males broadcast their desire for females. Occasionally though, a few individuals will stumble into our urban dwellings.

Few months back, an Asian Toad (Duttaphrynus melanostictus) made an appearance in my office. More precisely, it paid homage to a small corner. It was certainly a strange one. Throughout the whole time, it just sat there facing the wall with a contemplating look. It seemed overwhelmed by the wall and can’t decide what to do next. And it just stayed there the whole day and was so engrossed it totally ignored the mosquito sucking blood from its lower back.
There must be a scientific reason why it chose to sit at the corner throughout the day. But animals do strange things. Not all behaviour has to be explained and it is this erraticism that makes wildlife so fascinating.

Pictures taken at: National Biodiversity Centre, May 2008

Drepanosticta quadrata

2008-08-28T20:08:00.017+08:00

Damselflies from the family Platystictidae usually need close examination in particular the wings venation and anal appendages to identify the species confidently. Platysticids generally occurs in primary forests near small streams and the larvae have a distinctive disproportionately large head.
Within this family, the genus Drepanosticta is represented by eight species in Peninsular Malaysia. They usually fly close to streams, flitting within the forest understory. Both males and females typically have a blue spot at the abdomen base in which the shape of the spot can serve to identify some of the species from Peninsular Malaysia. Drepanosticta quadrata has a blue spot with a triangular pointed tip. This species was described from Singapore and according to references is known only from Singapore. This would thus make this damselfly a Singapore endemic. Even so, the website http://www.asia-dragonfly.net/ has this species as also occurring in China and Myanmar and has pictures of females from Johor. More work is perhaps needed to shed light on the true distribution of this damselfly as Albert Orr himself noted Drepanosticta spp. as data deficient with many species needing identity clarification.

Pictures taken at: Central Catchment Nature Reserve, August 2008

Update 2010Jan19th:

The blue marking on abdominal segments S8-9 is variable among species of this genus. D. quadrata is not endemic to S'pore. In fact, it is believed that D. quadrata and D. fontinalis could be the same species. (thanks Dr. Ian Choong)

References:

Orr, A. G., 2003. A Guide to the Dragonflies of Borneo. Their Identification and Biology, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Orr, A. G., 2004. ‘Critical species of Odonata in Malaysia, Indonesia, Singapore and Brunei’, in Guardians of the Watershed. Global status of dragonflies: critical species, threat and conservation, eds, V. Clausnitzer & R. Jodicke, International Journal of Odonatology, vol 7(2), pp. 371-384.

Orr, A. G., 2005. Dragonflies of Peninsular Malaysia and Singapore, Natural History Publications (Borneo) Sdn. Bhd, Malaysia

Octopus species

2008-08-03T20:34:00.010+08:00

This year is the International Year of the Reef and this coming National Day weekend, local marine lovers are having a series of talks and exhibitions to launch the event. This will be a great opportunity to highlight the amazing marine biodiversity Singapore has to the otherwise uninformed general public.

As part of the event, I’ll contribute an effort on this humble blog by drawing attention to the octopus, a creature which has always fascinated me with its amazing camouflaging abilities and known intelligence.

Octopuses can be found in a wide range of habitats. Many smaller species occur in rocky shores and coral rubbles where they forage in exposed pools during low tide periods. Most are excellent at camouflage and are able to match the colours of their surroundings with astounding dexterity. The video of this animal hunting says it all.

All octopuses use a strong neurotoxin at their salivary glands to immobilise prey when their long eight arms fan out into the nooks and crannies while hunting. The fast colour changes are presumably to camouflage it against predators although I remember reading somewhere that the changing colours are also a reflection of their ‘mood’.

Identification of octopuses to species level is not easy. Careful examination of their arm length; number of suckers; beak morphology etc is necessary. Nevertheless, small benthic dwelling inter-tidal species are from the family Octopodidae and this individual would be from the genus Octopus which most species belongs to. Many inter-tidal inhabitants are small. This octopus, with its arms fully extended, would be about the size of my two palms. For many people, all they see of octopuses is a blotch of black ink as the animal retreats into their hiding places at the first sign of danger. But any observer with patience and sensitivity will no doubt be rewarded with glimpses into the lives of our inter-tidal Singaporeans.

Happy National Day to ALL Singaporeans, big or small.

Pictures and videos taken at: A southern island of Singapore, July 2008

References:

Norman, M., 2003. Cephalopods. A World Guide. ConchBooks, Hackenheim, Germany.

Pentaceraster mammillatus

2008-06-22T01:15:00.008+08:00

It’s been almost two months since the discovery of a new sea star record at Cyrene Reef. Led by echinoderm expert Dr. David Lane, the find of Pentaceraster mammillatus created much excitement within local marine nature lovers. Not only that, the star created a chain of events, which I can now reflect on.

I'm heartened by the discovery not just because it’s a beautiful sea star, but more so that it was made from a combined effort of nature volunteers, government officials as well as a renowned scientist. All three parties whom are stakeholders working hand in hand for the betterment of Singapore’s natural heritage. As a result, Cyrene Reef now has a higher profile and has gotten the attention of the public. This is a major step towards creating a marine protected area for a reef with truly high biodiversity but also at the same time threatened by a busy shipping industry.

Publication of a subsequent news article on this discovery means everyone want a piece of the action. Many are eager to get associated, no matter how remotely, with this sea star. Working overtime editing the many drafts to satisfy all parties, the article was successfully published within a few days. For reasons known only to the perpetrator(s), the discovery also set off a series of flaming and argument on the Internet over basic taxonomy and even on the expertise of Dr. Lane. This has now resulted in what I can only best described as an uneasy truce among people working towards the same goal of marine conservation. How can we help nature when her very guardians are at odds?

Being previously found only in waters off eastern Africa and Red Sea region, P. mammillatus has been labeled an alien species by some. This is quite possible as Cyrene Reef is situated in the middle of Singapore’s shipping lanes and where ballast water could contain species not native to Singapore. This quickly became a thorny issue and politics soon came into play. To me, the wonderment of new discoveries is a major reason why I’m a student of nature. But when human politics interferes, my enthusiasm wanes quickly. I realise this is unavoidable and is something I would have to contend with. However, as much as possible, I shall do the science and leave the politics to the policy makers.

In retrospect, P. mammillatus had not only reinforced my love for nature’s possibilities but also gained me further insights into the different shades of human nature. Humans are after all nature’s child too.

Pictures taken at: Cyrene Reef, April 2008

References:

Clark, A. M. & F. W. E. Rowe, 1971. Monograph of the Shallow-Water Indo-West Pacific Echinoderms, British Museum (Natural History), London.

Prodasineura humeralis; Pseudagrion pruinosum

2008-05-21T23:48:00.021+08:00

Some of the rarest damselflies in Singapore are restricted to the remaining forested streams in our nature reserves. It is always a pleasure to encounter them and more so to witness an intimate affair. I recently sighted two rare species at the same location along a clear flowing stream.

The first was Prodasineura humeralis. It is quite common in Peninsular Malaysia but in Singapore, it was first recorded only in 2006. The prominent linear orange markings are distinctive. There are several species from the genus with very similar orange/yellowish markings. In fact P. humeralis was previously listed as P. verticalis from Peninsular Malaysia so it seems there is a degree of interspecific and intraspecific variations. More work on the many species from this genus awaits further investigations. Prodasineura species usually perch in sunlit spots along forest streams and are in high densities where they occur. I saw three of them within the same area.

Just about 50cm away was a mating pair of Pseudagrion pruinosum. The intimate pair was oblivious to my presence thus enabling me to document their love tryst.

After about 10 minute’s copulation, the pair flew down to the stream and the female started ovipositing.

After a while, the male released his grasp and the female descended underwater.

The video clearly shows the female searching for ovipositing spots with her abdomen. She surfaced and flew off easily due to the fact that her forewings remained dry thanks to it being shielded by the closed hindwings.

Whilst the female was submerged, the male waited nearby on a leaf. The instant she surfaced, he grasped her again in eagerness for another round of mating.

This is the first time I witnessed such behaviour and am suitably thrilled. According to literature, underwater oviposition occurs only in endophytic odonates in particular the damselflies but this ovipositing mode is not a compulsory with regards to any particular species. Some advantages of underwater oviposition include exemption from interferences from males and protecting the eggs from desiccation.

Studying odonates has honed my patience and observational attributes. I eagerly anticipate the next exciting observation in the field.

Pictures and videos taken at: Mandai forest, May 2008.

References:

Corbet, P. S., 1999. Dragonflies: Behaviour and Ecology of Odonata. Cornell University Press, New York.

Orr, A. G., 2003. A Guide to the Dragonflies of Borneo. Their Identification and Biology, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Orr, A. G., 2005. Dragonflies of Peninsular Malaysia and Singapore, Natural History Publications (Borneo) Sdn. Bhd, Malaysia

Rhyothemis phyllis

2008-04-26T16:48:00.009+08:00

A large swarm of Rhyothemis phyllis was encountered recently. There was at least 50 or more individuals flying around within a small opening in the forest. This species is known to form large swarms where they engage in rather slow, gliding midair foraging. Aggregation of foraging dragonflies has been well reported by odonatologists. In fact mass swarms like this occur more often in lee situations where there is shelter from wind.

R. phyllis is one of the most commonest species and very easily recognised by its wing patterns. A close up shot allows me to examine the intricate details of its wings. In terms of aerial versatility and agility, dragonflies probably stand at the peak of flight evolution among the insects or even some birds. Two wing structures play a key role. The nodus helps in the elastic tension thus allowing strong twisting and also as a shock absorber. The pterostigma at the distal edge on the wings provides favourable pitching moments during wing flapping acceleration. This then raises the critical gliding speed where self-excited vibrations take place therefore enabling a more efficient wing stroke with less power expenditure.

While out on survey work, I’m always the one chasing after dragonflies. So it was a good change to have dragonflies flying all around me uninhibitedly.

Picture and video taken at: Western Singapore, January 2007 & April 2008.

References:

Corbet, P. S., 1999. Dragonflies: Behaviour and Ecology of Odonata. Cornell University Press, New York.

Norberg, R. A. 1972. ‘The pterostigma of insect wings, an inertial regulator of wing pitch’, Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology, vol. 81 (1), pp. 9-22.

Orr, A. G., 2003. A Guide to the Dragonflies of Borneo. Their Identification and Biology, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Tyriobapta torrida

2008-03-27T22:05:00.013+08:00

Females of different dragonfly species have different ovipositing modes. Scientists classify the different modes into three broad categories: endophytic (oviposition inside plants), exophytic (oviposition on anything except plants, which is water or substrate) and epiphytic (ovipositing on plants).

I’ve seen females ovipositing several times while out in the field. The most recent encounter gave me a chance to record videos of a particular female ovipositing in ultra speed mode.

This is the female of Tyriobapta torrida. She was flying in a circular motion at high speed and using the trajectory force to project water droplets and her eggs onto the water edge. Its amazing how fast she was flying and I can only imagine the aerodynamics involved. The lift and drag forces must be rather intense as well as the wings locomotion in overdrive to maintain the flight pattern. Not only that, she was going at it for almost 7-8 minutes. This is a lot of energy expended to produce the next generation. If only I can view this video in slow motion, which will certainly give an insight into the flight mechanics.

All the while, the mate-guarding male was hovering nearby. T. torrida males are easily recognised by the dark iridescent patch on the hind wing base. This species is rather common in our forests. T. torrida is the largest species within its genus. Where they occur, they are usually abundant with several individuals occupying and disputing small territories. Sexual activities are known to peak at around noon.

Corbet’s book described females from some other species diving underwater and ovipositing while submerged. Some species have been recorded to descend down to 1m depth. Now that is really a sight I want to behold.

This post is dedicated to Professor Philip Corbet who passed away on 13th February 2008 aged 78.

Pictures and videos taken at: Western Singapore, October 2007 & Venus Trail, March 2008.

References:

Corbet, P. S., 2004. Dragonflies: Behaviour and Ecology of Odonata. 2nd edition, Harley Books, Colchester.

Orr, A. G., 2003. A Guide to the Dragonflies of Borneo. Their Identification and Biology, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Orr, A. G., 2005. Dragonflies of Peninsular Malaysia and Singapore, Natural History Publications (Borneo) Sdn. Bhd, Malaysia

Robber Fly

2008-03-22T18:07:00.011+08:00

I was on Petai Trail recently and chanced upon this weird insect perching on a twig. It was motionless and thus perfect for a macro shot. It is about half the size of a palm and at first sight, looked rather fragile with its long abdomen hanging in mid-air. The poor insect seemed to be hanging for dear life.

It was only after I took a closer look at the picture and identification by Yixiong that I realised I’ve caught a glimpse of a fearsome predator of the insect world.

This is a Robber Fly from the Order Diptera (true flies). True flies are distinguished from other flying insects by having only a single pair of wings while their hind wings are greatly reduced into flight balancing organs called halteres. Robberflies belong to the Asilidae family but we are not sure what this particular species is.

Taxonomic classification aside, it is the ecology of robber flies that’s really fascinating. They prey on all sorts of insects, from easy ones like butterflies to prey that can put up a good fight like wasps, bees, spiders and dragonflies. In fact, some species are specialist hunters who target specific prey. Upon successful capture, a robber fly will inject its prey with saliva containing neurotoxin and other enzymes which immobilise the prey and liquify the tissue. Thereafter, the robber fly will suck on the soupy meal.

Not sure how well robber flies are studied in Singapore. But unsurprisingly, there’s tons of information on the web. This website http://www.geller-grimm.de/general.htm is one of the more comprehensive.

Pictures taken at: Petai Trail, March 2008.

References:

Geller-Grimm, F., T. Dikow & R. J. Lavigne. Robber Flies (Asilidae).
http://www.geller-grimm.de/asilidae.htm

Voluta nobilis

2008-03-02T00:01:00.006+08:00

The second episode of Once Upon A Tree: Tides and Coastlines brought us back to nostalgic Singapore. Those were the days when people live much of their lives connected to the sea, for work as well as for play.

Work because, for example, The Raffles Hotel once stood just by the beach and would even be flooded during times of extreme high tides. Play, because trips to the sea then mean clear water, good fishing and excellent exploring on the seashore. The elders interviewed on the show mentioned big corals, huge fishes and dolphins were a regular sight. I’m quite sure one of the creatures they would have seen often too is this magnificent seashell, Voluta nobilis.

Voluta nobilis or “kilah” in the local language was once very common. They are now rarely encountered but still exists, mainly on our offshore islands. This pretty individual was spotted at Pulau Semakau recently. It’s been a while since I saw a live one, most of the time I found them as empty shells inhabited by hermit crabs. This individual’s siphon was fully extended as it searched for prey like bivalves. It will use its huge foot to suffocate and force its prey to open their shelves for oxygen. Once that occur, then its mealtime for V. nobilis.

Perhaps the elders from the documentary would be glad to know “kilah” can still be found in our waters.

Pictures and videos taken at: Pulau Semakau, February 2008.

References:

Tan, K. S. & L. M. Chou, 2000. A Guide to Common Seashells of Singapore. Singapore Science Centre, Singapore

Diplacodes nebulosa; Rhyothemis triangularis; Lesser Whistling-duck

2008-01-22T00:38:00.000+08:00

Another odonate survey with the gang, this time to the ponds of Marina East. The habitat is dominated by thin grass-like vegetation. Not very sure what plant it is but most probably belongs to the Cyperaceae family. The water itself is full of brownish algae and there’s a slight smell typical of eutrophic waters.

Nevertheless, this is an excellent habitat for odonates. They are in high abundance and are very active thanks to the warm morning sunshine. The most numerous species is Diplacodes nebulosa. They are very distinct due to the dark tips on their wings. All the males are defending a small territory and chasing each other, zipping all over the water surface.

The most striking dragonfly there has to be Rhyothemis triangularis, aptly named due to the deep metallic blue triangular patch on its hind wings. Dragonflies from the genus Rhyothemis characteristically have short abdomens with broad hind wings. Some of them are quite common in open countries or streams in swampy forest. R. triangularis is common and widespread in Asia. However in Singapore they are rather uncommon as habitats akin to the Marina East ponds are few and far between.

But odonates are not the only creatures inhabiting the ponds. From afar, a Lesser Whistling-duck (Dendrocygna javanica) made an appearance. This is a nationally vulnerable bird. Once again habitat loss is the main cause as freshwater ponds are destroyed when urbanisation encroaches. This bird has an estimated population of 250 in Singapore.

As we left Marina East, I sensed a “melancholy in the wind and sorrow in the grass” (Charles Kuralt). How much longer will this location remain as it is? Its neighbour at Marina South is already morphing into the Integrated Resort. Rumour has it that Marina East will become a golf course. “Another golf course?!” Tang sighed.

Perhaps we could get the developers to build the golf course while preserving this small nature haven? My mind begins to sparkle…

Pictures taken at: Marina East, January 2008.

References:

Orr, A. G., 2005. Dragonflies of Peninsular Malaysia and Singapore, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Wang, L. K. & C. J. Hails, 2007. ‘An annotated checklist of the birds of Singapore’, The Raffles Bulletin of Zoology, Supplement 15: 1-179.

Purple Swamphen

2008-01-06T02:57:00.000+08:00

We spent a relaxing Christmas afternoon in laidback Kranji countryside. After a sumptuous lunch, we headed to the farms dotting the area and as the sun began to set, we took a leisurely hike towards the Kranji Marshes.

The scenic Kranji Marshes hug along much of Kranji Reservoir’s perimeter. Marshlands are an increasingly rare habitat in Singapore as many have been lost to urban development.

As we took in the view, a series of loud chuckling and cackling greeted us. Out of a sudden, two dark purplish-blue birds with bright red bill emerged from the water vegetation. What a fortune! Its the unmistakable Purple Swamphens (Porphyrio porphyrio). I’ve previously only caught a glimpse of this elusive bird a year back so this was an excellent Christmas present from Mother Nature. Not only did the birds made an appearance, one of them was foraging uninhibitedly about 30metres away.

Purple Swamphen is a member of the Rail family which also includes the more common White-breasted Waterhen (Amaurornis phoenicurus). They inhabit mostly swampy and marshy habitats. These birds have a clearly distinguishable robust stout body, short tail and are rather weak fliers. Their huge red bill, red frontal shield, red legs and purplish-blue plumage make them one of Singapore’s most attractive marshland birds.
Purple Swamphens have a very conspicuous white undertail covert. The birds will constantly flash this white rump patch by jerking their tail up and down. Research suggests that this behaviour is a form of prey-predator communication whereby a bird’s state of alertness is communicated to a potential predator, thus discouraging the predator from a vigilant prey. Perhaps that was exactly what the bird was trying to tell us that Christmas afternoon. We certainly would not have the heart to harm such a fine-looking creature.

Pictures taken at: Kranji Marshes, December 2007.

References:

Alvarez, F. 1993. ‘Alertness signalling in two rail species’, Animal Behaviour, vol. 46 (6), pp. 1229-1231.

Robson, C., 2000. A Field Guide to the Birds of South-east Asia, New Holland Publishers (UK) Ltd, London.

Aeolid Nudibranch

2007-12-16T02:56:00.000+08:00

Nudibranchs have got to be one of the prettiest and most colourful marine invertebrates. No dives or intertidal walks would be complete without seeing one. I have been very fortunate to see several different species throughout the years. Nudibranchs are classified into four suborders and my personal favourite are nudibranchs from the suborder Aeolidina.

Aeolids are typically longish in body shape and have a pair of cephala tentacles that’s distinct from rhinophores. But what makes them stand out are the rows of cerata on their back. I always thought it gives them a funky and rebellious demeanor.
The cerata are actually respiratory organs. In certain species, a cnidosac occurs at the tip of each ceras. These functions as storage for nematocysts capsules for defence and many aeolids obtain the stinging nematocysts from their food source, for example hydroids.

This aeolid nudibranch spotted at Beting Bronok is an absolute attraction. It most probably is from the family Facelinidae. For exact identification to species, its radula would have to be examined.

A team of University of Queensland researchers studying sea slug pheromones have named the chemicals attractin, enticin, temptin and seductin……..very apt names for an alluring group of animals.

Pictures taken at: Beting Bronok, October 2007.

References:

Behrens, D. W., 2005. Nudibranch Behavior. New World Publications, USA.

Graduate Contact 2007, No. 36. University of Queensland, Australia.

Ceriagrion cerinorubellum; Agriocnemis femina; Lynx Spider

2007-11-20T18:34:00.000+08:00

The world of insects is filled with peril as many of them are ferocious predators and it is really a survival of the fittest. A survey at Lorong Halus gave me an exciting insight into their prey-predator relationship.

Agriocnemis femina is a small damselfly measuring up to only about 17mm in body length. This species undergoes colour changes with maturity and mature males have a whitish synthorax. This dainty damselfly is common around ponds and drains and they share the same habitat with another damselfly species, Ceriagrion cerinorubellum.

C. cerinorubellum is about a size bigger than A. femina. They are fierce predators and it was not long before we chanced upon a C. cerinorubellum attacking and consuming an A. femina. The prey’s head had been consumed but we could clearly see that it was an immature male A. femina from the orange tip at the abdomen. The C. cerinorubellum was so engrossed on lunch that it simply ignored me as I approached it really close to get a clear picture.

In nature, it is a case of eat or be eaten. This time the predator became the prey. A Lynx Spider (Oxyopes sp.) had captured a C. cerinorubellum. Lynx Spiders have keen eyesight and they hunt down their prey with very agile movements. This individual must have sprung an ambush on C. cerinorubellum which did not stand a chance once the spider sank in its fangs.

As we were leaving Lorong Halus, C. cerinorubellum reminded us that it is still an awesome predator among the small invertebrates. I managed to record a video of one consuming a fly-like insect. I would imagine the chase prior to capture must be quite a dogfight, a battle for air supremacy on a miniature scale.

These little insects might not have the iconic status of lions or tigers. But they are just are vicious and ruthless when it comes to feeding time. I think back to the movie ‘Honey, I Shrunk the Kids’. With these fearsome insects around, that would be a real nightmare comes true.

Pictures and video taken at: Lorong Halus, November 2007.

References:

Koh, K. H. J., 1989. A Guide to Common Singapore Spiders. Singapore Science Centre.

Orr, A. G., 2005. Dragonflies of Peninsular Malaysia and Singapore, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Stichopus herrmanni vs Stichopus chloronotus

2007-11-08T16:47:00.000+08:00

The identity of the sea cucumber (see post) spotted at Pulau Semakau in August has finally been confirmed as Stichopus herrmanni. Below is the reply from Dr. Claude Massin from the Royal Belgian Institute of Natural Sciences in Belgium.

“Dear Colleague,

At first glance your specimen could be confused with a Stichopus chloronotus. However, if S. chloronotus has large dorsal papillae with orange tips, these papillae are always well aligned on rows. On your specimen, all the dorsal papillae have the same size and are evenly dispersed. This colour pattern is more reminiscent of S. herrmanni. Moreover, you have a lot of rosettes in your preparations. In S. chloronotus the rosettes are said to be absent or very rare. If you check the size of the C-shaped rods, it is also easy to separate S. chloronotus from S. herrmanni.

S. chloronotus: in dorsal body wall, maximum 45 µm long; in ventral body wall maximum 70 µm long.
S. herrmanni: in the dorsal body wall, 35-100 µm long; in the ventral body wall maximum 150 µm long.

I think your specimen is a particularly dark morph of S. herrmanni.”

Stichopus herrmanni (dark form)

Stichopus chloronotus

Stichopus herrmanni (greyish-green form)

In all the previous reference books and papers, pictures of S. herrmanni are always greyish-green or brownish-green in colour. Looks like we have observed a rather rare dark morph of this species.

Several studies on their reproductive cycle have been conducted in various parts of the world. In Iran, S. herrmanni spawn during the peak of summer in July-August while in New Caledonia, they spawn during the months of January-February. In both cases, warmer seawater temperature is the trigger for reproduction. I wonder what is the situation in Singapore where there is no significant seasonal climate differences in tropical Southeast Asia.

I’ve had the opportunity to interact with several echinoderm experts around the world and have gained much knowledge. I certainly look forward to more advice from them.

Pictures taken at: Pulau Semakau, August 2007; S. chloronotus and S. herrmanni (greyish-green form) are from the book Taxonomie des holothuries des Comores.

References:

Massin, C., Y. Zulfigar, A. S. H. Tan & S. Z. Rizal Boss, 2002. ‘The genus Stichopus (Echinodermata: Holothuroidea) from the Johore Marine Park (Malaysia) with the description of two new species’, Bulletin de l’Institut Royal des Sciences Naturelles de Belgique, Biologie, vol. 72, pp. 73-99.

Samyn, Y., D. VandenSpiegel & C. Massin, 2006. Taxonomie des holothuries des Comores, Abc Taxa (Volume 1), Belgium.

Tehranifard, A., S. Uryan, G. Vosoghi, S. M. Fatemy & A. Nikoyan, 2006. ‘Reproductive cycle of Stichopus herrmanni from Kish Island, Iran’, SPC Beche-de-mer Information Bulletin, vol. 24, pp. 22-27.

Sand Star

2007-09-30T16:45:00.000+08:00

Sand Stars (Archaster typicus) is one of the more easily seen sea star on our shores. During low tide, they will emerge from the sandy sediments and they could also be located by the star-shaped impressions left on the sand. This is especially so on the sandy shores of Pulau Semakau. We spotted several mating pairs and the Temasek Poly students wondered how copulation takes place.

A. typicus belongs to the family Archasteridae. This is a small family with only one single genus, Archaster. Sand Star males are slightly smaller than females and a mating pair will always involve the male superposed on top of the larger female. However, fertilization occurs externally where both male and female synchronize the release of sperm and eggs. Thus copulation, which infers internal fertilization, is probably the wrong term to use. Pseudocopulation is the term widely used by scientists.

Sand Star is one of only two sea star species currently known to perform male-on-female superposition sexual behaviour. Most other species conduct aggregate spawning. It is not exactly clear why Sand Stars superpose during breeding. It could either be to increase the chances of fertilization when the eggs and sperm are dispersed into the water or it is a mate guarding behaviour.

Pictures taken at: Pulau Semakau, August 2007.

References:

Komatsu, M, 1983. ‘Development of the Sea-star, Archaster typicus, with a Note on Male-on-female Superposition’, Annotationes Zoologicae Japonenses, vol. 56 (3), pp. 187-195.

Lane, D. J. W. & D. VandenSpiegel, 2003. A Guide to Sea Stars and other Echinoderms of Singapore. Singapore Science Centre, Singapore.

Gold-spotted Mudskipper

2007-09-15T03:02:00.000+08:00

It has been a while since I stepped into a mangrove and I’m beginning to miss the mudskippers, or as Rachel would affectionately call them the ‘doink-doink-doinks’ because of their locomotion on land. Their movement of pectoral fins pulling and dragging the body forward always leaves a distinctive trail on the mudflat.

Gold-spotted Mudskippers (Periophthalmus chrysospilos) have pretty orange spots along their body and some of them can appear yellowish in colour. They are rather common and easy to identify from afar. One of the diagnostic features separating this species from other mudskippers is their fully fused pelvic fins that form a round disc.

P. chrysospilos has a small gill area compared to other mudskippers. They are thus less efficient in aquatic respiration and so more adapted to land than water. Their breeding period is thought to be between May and July when they’ll become less seen as they spend more time in their burrows. Males will attract females to their burrows with vigorous courtship displays. Once paired, the male will defend his burrow and surrounding territory against all comers including mangrove crabs!

Pictures taken at: A southern offshore island, December 2006; A northern offshore island, May 2006 and western part of Singapore, January 2007.

References:

Ip, Y. K., S. F. Chew, L. L. Lim & W. P. Low, 1990. ‘The Mudskipper’, in Essays In Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, eds, L. M. Chou & P. K. L. Ng, Department of Zoology, National University of Singapore.

Larson, H. K. & K. K. P. Lim, 2005. A Guide to Gobies of Singapore, Singapore Science Centre, Singapore.

Stichopus cf. herrmanni

2007-08-26T12:52:00.000+08:00

Another sea cucumber!! This time its from the family Stichopodidae.

I chanced upon it during a recent seagrass monitoring at Pulau Semakau. It has a thick body wall, a lumpy body surface and is covered with orange papillae which contrast brightly against the black body surface.

Following the advice from Dr. David Lane, I proceeded to obtain some tissue samples from the dorsal tegument before returning the creature back to the sea.

After several failed attempts at ossicles preparation from a different species, I decided to try again. And voilà! The beautiful ossicles appeared as I adjusted the microscope’s focus. Intricate tables, C-shaped, S-shaped and branched rods of various patterns came into view. It’s a real wonder that these microscopic skeletons have, over evolutionary time, been reduced to these beautifully elaborate 3-D structures.

Based on the references, the ossicle shapes and general morphology would identify it as a Stichopus sp. and it most resembles Stichopus herrmanni. However none of the references noted S. herrmanni appearing in black. Looks like I’ll have to search deeper into sea cucumber taxonomy.

Sea cucumber ossicles, the real beauty is within.

Pictures taken at: Pulau Semakau, August 2007.

References:

Clark, A. M. & F. W. E. Rowe, 1971. Monograph of the Shallow-Water Indo-West Pacific Echinoderms, British Museum (Natural History), London.

Colin, P. L. & C. Arneson, 1995. Tropical Pacific Invertebrates. A Field Guide to the Marine Invertebrates Occurring on Tropical Pacific Coral Reefs, Seagrass Beds and Mangroves, Coral Reef Press, U.S.A.

Lane, D. J. W. & D. Vandenspiegel, 2003. A Guide to Sea Stars and other Echinoderms of Singapore, Singapore Science Centre, Singapore.

Ictinogomphus decoratus

2007-08-12T17:07:00.000+08:00

Most of the commonly seen dragonfly species belong to the family Libellulidae. Some of them have adapted to urbanisation and are thriving very well in the ponds and canals within our landscaped parks and gardens. Dragonflies from the family Gomphidae are less common. They are more sensitive to environmental degradation and thus in Singapore; they are more easily encountered in natural streams and water bodies.

Gomphids' pair of eyes is well separated and this is one of the features differentiating them from other dragonfly families. There are only about eight recorded gomphid species in Singapore. Yangchen spotted this striking Ictinogomphus decoratus during one of our surveys. Ictinogomphus species are large and they like to breed largely in standing water. I. decoratus in particular inhabits ponds and dams which makes them the most common among Singapore’s gomphid dragonflies.

This year we celebrate National Day at Marina Bay. Not many of the spectators would know that the few sedge ponds existing in the nearby Marina South and Marina East would soon be cleared for development. And so we will lose another location which supports good dragonfly diversity.

Pictures taken at: Western part of Singapore, August 2007.

References:

Orr, A. G., 2003. A Guide to the Dragonflies of Borneo. Their Identification and Biology, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Orr, A. G., 2005. Dragonflies of Peninsular Malaysia and Singapore, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Cake Star

2007-07-13T11:09:00.000+08:00

A bright red Cake Star (Anthenea aspera) beckoned at Merawang Beacon!!

I was surprised to see this asteroid fully exposed during low tide. Its intense redness is a standout and it is large with an arm radius of about 11cm.

Anthenea aspera is rare within the Indo-Pacific region. Of the 31 asteroid species currently known from Singapore waters, A. aspera is among the largest. Their colour and patterns are variable ranging from dark green to dark pink. In Singapore, this species is first found from Changi in 1992 and has since been spotted at Chek Jawa and Pulau Semakau. Looks like they could also be found from our western shore.

The large bivalved pedicellariae on the oral surface is a typical feature of A. aspera. They are defensive structures that can be used to snip off any settling larvae and thus protect the Cake Star from encrusting organisms.

This Cake Star from Merawang Beacon is a real beauty!

Pictures taken at: Merawang Beacon, March 2007.

References:

Lane, D. J. W. & D. VandenSpiegel, 2003. A Guide to Sea Stars and other Echinoderms of Singapore. Singapore Science Centre, Singapore.

VandenSpiegel, D., D. J. W. Lane, S. Stampanato & M. Jangoux, 1998. ‘The asteroid fauna (Echinodermata) of Singapore, with a distribution table and illustrated identification to the species’, The Raffles Bulletin of Zoology, vol. 46 (2), pp. 431-470.

Pond Wolf Spider

2007-06-16T17:39:00.000+08:00

While in the midst of spot lightning for the Barn Owl, I can’t helped but noticed the many Wolf Spiders’ eye shine on the grassy field. They seemed to be calling out for my attention.

Zeroing on an individual, I was pleasantly surprised to see a female spider carrying her spiderlings on her back. There are so many spiderlings that I could hardly see the mother at all. A study has concluded that mothers with spiderlings are more mobile with greater directional movement compared to other females. This higher mobility together with the gradual dismounting of spiderlings will aid in spreading the young throughout their habitat and thus avoid kin competition.

We noticed a male nearby following the mother. Yixiong tried to catch it and was promptly bitten. Ha-ha…. the spider lived up to his name.

Pond Wolf Spiders (Pardosa pseudoannulata) are fast running predators and can be found on the ground near water bodies. These spiders from the family Lycosidae has their eight eyes arranged in three rows of 4, 2, 2.

Pictures taken at: Pierce Road, May 2007.

References:

Bonte, D., S. Van Belle & J-P. Maelfait, 2006. ‘Maternal care and reproductive state-dependent mobility determine natal dispersal in a wolf spider’, Animal Behaviour, doi:10.1016/j.anbehav.2006.06.021

Koh, K. H. J., 1989. A Guide to Common Singapore Spiders. Singapore Science Centre.

Murphy, F. & J. Murphy, 2000. An Introduction to the Spiders of South East Asia, Malaysian Nature Society. United Selangor Press Sdn. Bhd, Kuala Lumpur.

Orange-bellied Flowerpecker

2007-06-03T16:22:00.000+08:00

Sometimes nature will present its intimate moment at the most unexpected time. You just have to be lucky and ever ready to capture it.

We were hiking along Macritchie Reservoir when a pair of Orange-bellied Flowerpecker (Dicaeum trigonostigma) made an unannounced appearance. They fleeted among the Singapore Rhododendron (Melastoma malabathricum) bushes feeding on its fruits. The birds were only about two metres away and were uninhabited by our presence. As I took the pictures, Weiling’s nature guiding instinct kicked in and she promptly pointed the birds to a couple of passing tourist hikers. I hope the birds made the tourist’s day.

Male Orange-bellied Flowerpeckers have a beautiful orange breast and back with yellowish vent and coverts while the females are duller. They are our common resident. They can be seen flying energetically among the tree tops feeding on nectar, small fruits and insects.

The birds we saw sure looked like a loving couple.

Pictures taken at: Macritchie Reservoir, May 2007.

References:

Robson, C., 2000. A Field Guide to the Birds of South-east Asia, New Holland Publishers (UK) Ltd, London.

Polyplectana kefersteinii

2007-05-29T00:05:00.000+08:00

I am now very intrigue by sea cucumbers. Everything about them fascinates me. Their docile nature belies a nasty defence mechanism; the myriad colours and sizes sea cucumbers can occur; they are not very well studied with many undescribe species and their overall squeamishness which, strangely, I find really appealing. And of course some of them really look like big poo.

There are about 1400 known species worldwide. They are classified into six orders and in total 25 families. I’ve so far seen representatives from five families on our intertidal shores. The latest is this one representing the synaptids.

A typical synaptid from the Order Apodida has no tube feet, has a very thin and sticky body wall and has no respiratory trees. Apodids’ oral tentacles can be simple or digitate or, like this individual has so beautifully demonstrated, feather-like.

This species is most probably a Polyplectana kefersteinii. But of course we would have to examine its microscopic ossicles to be 100% certain of the identification.

Picture and video taken at: A southern offshore island, March 2007 and Pulau Semakau, May 2007.

References:

Kerr, A. M., Holothuroidea. Sea cucumbers.
http://www.tolweb.org/Holothuroidea

Lane, D. J. W. & D. Vandenspiegel, 2003. A Guide to Sea Stars and other Echinoderms of Singapore, Singapore Science Centre, Singapore.

Ceriagrion cerinorubellum

2007-05-13T15:01:00.000+08:00

Sex. What is your favourite position? For Odonates, it is the Wheel.

I spied this pair of Ceriagrion cerinorubellum damselfly in the heat of passion during my fieldwork. The female below had curled her abdomen towards the male’s genitalia to receive the sperm. And with that, the couple formed a beautiful heart shape wheel position. But all is not lovey dovey because the pair was engaged in a reproduction battle of wits.

The pair was locked in this position for almost 10 minutes. This long copulation period allows the male damselfly to remove rival sperm from the bursa copulatrix, a copulatory structure in the female. However in a classic case of cryptic female choice, the female retains control over reproduction as she can control the sperm reserves in her spermatheca. Knowing this, the male will prolong copulation to elicit the female to eject rival sperm and tempt her to use his sperm for fertilisation.

Thank goodness human reproduction is not this complicated.

C. cerinorubellum is a very common and colourful damselfly. They occur frequently in suburban gardens, drains and ponds. They are also vicious predators capable of tackling other damselfly species twice their size.

Colourful, ferocious and sexually competitive. Quite a character for a tiny insect!

Pictures taken at: A northern offshore island, March 2007 and western part of Singapore, February 2007.

References:

A. G. Orr., 2003. A Guide to the Dragonflies of Borneo. Their Identification and Biology, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

A. G. Orr, 2005. Dragonflies of Peninsular Malaysia and Singapore, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Uhia, E & A. C. Rivera, 2005. ‘Male damselflies detect female mating status: importance for postcopulatory sexual selection’, Animal Behaviour, vol. 69 (4), pp. 797-804.

Polychaete (Family: Polynoidae)

2007-04-29T01:05:00.000+08:00

Prof. Peter Ng gave a good speech at an Earth Day event last weekend. He touched on nature conservation in Singapore. Two main points stuck in my mind: 1) There is much more to discover from Singapore’s natural habitats. 2) We have to conserve and protect because our natural heritage belongs to us and nobody else and is ours to keep.

His speech strengthened my conviction to partake in local nature-related work. We must fight for nature conservation because if we don’t, we’ll not only lose our heritage but also things that maybe new to science.

Small invertebrates are a case in point. Many of them have been largely ignored by science. Some of them are difficult to study, some are hard to find and most are largely disregarded because they lack the ‘cute’ factor. But in actual fact, many invertebrates are fascinating and cute.

When I spotted this little critter, I thought it is some kind of sea slug. On closer examination, it turns out to be a polychaete from the family Polynoidae. It hardly looks like a worm and even has a bug-like motion.

There are 64 polychaete species in Singapore waters with only two species from the Polynoidae family. This is based on the last major polychaete study by Prof. Chou in 1993 where he reported 29 first time records for Singapore. 14 years has passed and Wilson has found several more new records.

Singapore certainly has many more minute fauna waiting to be revealed.

Picture and video taken at: A southern offshore island, March 2007.

References:

Tan, L. T. & L. M. Chou, 1993. ‘Checklist of polychaete species from Singapore waters (Annelida)’, The Raffles Bulletin of Zoology, vol. 41 (2), pp. 279-295.

Slender-lined Shrimp-goby

2007-04-16T19:59:00.000+08:00

I’ve little knowledge on gobies before I started my current project. A year has passed. Through readings, consultations and trials and errors, I’ve gained much understanding of their ecology. Some of the most colourful gobies are the shrimp-gobies and their symbiotic relationship with the shrimps is most fascinating.

The Slender-lined Shrimp-goby (Cryptocentrus leptocephalus) is usually found on shallow reefs. They share a burrow with alpheid shrimps. The communication between goby and shrimp is ingenious. As the goby sits at the burrow entrance as a ‘guard’, the shrimp will touch the goby with its antennae. At the first sign of danger, the goby will flick its tail and both goby and shrimp will retreat into the burrow for safety. Researchers have shown that in the absence of shrimps, the gobies will not give a warning signal.

Ethology is an aspect in biological science that I find most interesting. Animals have many inventive ways to communicate both intraspecifically as well as interspecifically. Gaining insights into their behaviour and its meaning give me a sense of challenge. And the intimate knowledge gained reinforced my understanding of nature’s intricate connections at all levels. I hope to do some proper animal behaviour research in the future.

Picture taken at: Terumbu Pempang Laut, July 2006.

References:

Larson, H. K. & K. K. P. Lim, 2005. A Guide to Gobies of Singapore, Singapore Science Centre, Singapore.

Preston, J. L., 1978. ‘Communication systems and social interactions in a goby-shrimp symbiosis’, Animal Behaviour, vol. 26 (3), pp. 791-802.

File Shell

2007-03-26T17:53:00.000+08:00

This File Shell (Lima lima) was uncovered when we were looking for worms under some rocks at Tanjung Rimau. Its appearance took us by surprise. We were both fascinated by the bright red tentacles and its shell valves clapping locomotion.

File Shells use an adductor muscle to clap their valves in order to achieve their free-swimming ability. The red tentacles are sticky and as a mean of defence, they’ll break off when attached to predators. This will thus allow the shells to make a quick getaway.

Our intertidal shores are full of captivating fauna from a myriad of forms and colours. The species diversity is mind-boggling.

Do go out there and explore all the nooks and crannies!!

Pictures taken at: Tanjung Rimau, February 2007.

References:

Tan, K. S. & L. M. Chou, 2000. A Guide to Common Seashells of Singapore, Singapore Science Centre, Singapore.

Tan, L. W. H. & K. L. Ng, 1988. A Guide to Seashore Life, Singapore Science Centre, Singapore.

Nannophya pygmaea

2007-03-10T15:40:00.000+08:00

I remember a rather horrifying encounter with a dragonfly when I was very young.

I was a five year old kid visiting my grandma’s in a kampong in Malaysia. We were sitting at the dinning table when my uncle approached me with a gift. As he opened his fist, a huge back dragonfly suddenly flew into my face. It gave me a fright!! To make matters worse, he was holding a string tied to its abdomen and so the flying ‘monster’ was zipping all over me and the dining table. In an instant there was complete chaos as the dragonfly crashed into everyone and right into the dishes scattering all the food. It finally demised in a bowl of hot soup and my uncle got an earful from my relatives.

Now I’ve re-acquainted with the dragonflies and developed an immense liking for their beauty.

Dragonflies come in all colours imaginable. Their zipping and hovering flight are a delight to watch. They play an important role as indicators of environmental disturbances and many consider them a indicator species in streams and marshy habitats.

Male

Female

Nannophya pygmaea is one of the smallest dragonfly in the world. The adult male is bright red and will defend a small territory of only about one metre square. An interesting study on its territorial mating behaviour revealed that variations in male mating success is correlated more to the number of sunny days and less on male size.

Singapore’s plan to transform its concrete canals into landscaped channels has brought odonates into the forefront among local naturalists. There is now an initiative to study and update the status of Odonata in urbanised S’pore.

For me, this old song from 小虎队 best sums up the dragonflies.

飞呀飞呀
看那红色蜻蜓飞在蓝色天空
游戏在风中不断追逐它的梦
天空是永恒的家大地就是它的王国
飞翔是生活
我们的童年也像追逐成长吹来的风
轻轻地吹著梦想慢慢地升空
红色的蜻蜓是我小时候的小小英雄
多希望有一天能和它一起飞
当烦恼越来越多玻璃弹珠越来越少
我知道我已慢慢的长大了
红色的蜻蜓曾几何时
也在我岁月慢慢不见了
我们都已经长大好多梦正在飞
就像童年看到的红色的蜻蜓
我们都已经长大好多梦还要飞
就像现在心目中红色的蜻蜓

Pictures taken at: Western part of Singapore, February 2007.

References:

Orr, A. G., 2003. A Guide to the Dragonflies of Borneo. Their Identification and Biology, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Orr, A. G., 2005. Dragonflies of Peninsular Malaysia and Singapore, Natural History Publications (Borneo) Sdn. Bhd, Malaysia.

Tsubaki, A. & T. Ono, 1987. ‘Effects of age and body size on the male territorial system of the dragonfly, Nannophya pygmaea rambur (Odonata: Libellulidae)’, Animal Behaviour, vol. 35 (2), pp. 518-525.

Holothuria leucospilota

2007-02-25T15:48:00.000+08:00

My initial impression of sea cucumbers was that they are really boring and rather disgusting creatures. They look like huge bloated worms and most of the time doing nothing but just….hanging around. But then I got my hands on some echinoderm books and I started to develop a liking for them, more so after encountering several sea cucumber species during the course of my work.

Sea cucumbers have evolved to lie on one side with the mouth and anus on opposite ends of the body. Their skeletons have been reduced to microscopic ossicles which are important in identifying species. Sea cucumbers feed by means of filtering suspended food particles or organic laden sediments using their feeding tentacles. They thus play an important role in helping to turn over reef sediments.

Holothuria leucospilota is one species I’ve encountered numerous times. They are usually exposed at low tide and are conspicuous in rock crevices. They kind of look like the excrement of a giant marine creature.

H. leucospilota is one of the species that ejects sticky white threads called Cuvierian tubules from the anus as a defence strategy. The repugnant tubules are believed to repel or entangle would be predators.

Sea cucumbers may be soft bodied and appear docile but they are not to be underestimated!

Pictures taken at: Terumbu Bukom, July 2006; St John’s Island, December 2006 and Lazarus Island, December 2006.

References:

Colin, P. L. & C. Arneson, 1995. Tropical Pacific Invertebrates. A Field Guide to the Marine Invertebrates Occurring on Tropical Pacific Coral Reefs, Seagrass Beds and Mangroves, Coral Reef Press, U.S.A.

Lane, D. J. W. & D. Vandenspiegel, 2003. A Guide to Sea Stars and other Echinoderms of Singapore, Singapore Science Centre, Singapore.

Colugo (Malayan Flying Lemur)

2007-02-15T18:33:00.000+08:00

I got to know Norman Lim when I volunteered for his Pangolin survey. He is a nice guy, scholarly and has tremendous passion for animals especially those poorly studied nocturnal creatures. He also has a sharp eye and is always spotting well camouflaged animals others would miss. His Honours Colugo project and recently published book open a window into the Colugo's secretive life.

There are only two species of Flying Lemur in the world. The Colugo (Cynocephalus variegatus) and the Philippine Flying Lemur (Cynocephalus volans). They are of course not related to Lemurs at all but belong to the order Dermoptera. The taxonomy of Flying Lemur has been of much debate. Recently, genetic studies suggest they maybe closely related to humans!

And of course Colugos are one of the few mammals that glide. I was lucky to witness the feat a couple of times and it was quite a sight as the animal spread its patagium and glided effortlessly onto a tree trunk metres away. During the day they’ll usually rest in a tree hole or roost by perching against a tree trunk. It takes a keen observer to spot them.

These individuals were seen at Bukit Timah Nature Reserve and near the Tree Top Walk.

There is an estimated population of about 1500 in our forests. They do not do well in captivity but ironically there is a small population of free ranging Colugos in the Zoo. It seems they can survive well in landscaped and fragmented habitats. Nonetheless, it is crucial for the relevant authorities to conserve its shrinking habitats and protect this native enigmatic animal.

Pictures taken at: A northern offshore island, November 2006; Bukit Timah Nature Reserve, September 2006 and Tree Top Walk, November 2006.

References:

Agoramoorthy, G., C. M. Sha & M. J. Hsu, 2006. ‘Population, diet and conservation of Malayan flying Lemurs in altered and fragmented habitats in Singapore’, Biodiversity and Conservation, vol. 15 (7), pp. 2177-2185.

Francis, C. M., 2001. A Photographic Guide to Mammals of South-east Asia, New Holland Publishers Ltd, United Kingdom.

Lim, N., 2007. Colugo. The Flying Lemur of South-east Asia, Draco Publishing & Distribution Pte Ltd and National University of Singapore, Singapore.

Mud Lobster

2007-02-04T17:13:00.000+08:00

We were just about to leave the survey site when Weiling and Shufen squealed in delight. They have sighted a Mud Lobster out of its mound!! We followed the bright red lobster as it scrambled over the mud mounds and debris.

We were urging it on and wondering where it was heading when it stopped and started digging into the mud. As it dug with its huge claws, we were expecting it to go right in. But surprisingly, it did a reverse maneuver and went in abdomen first thus completing a perfect camouflage!

It was indeed very fortunate for us to witness this common but rarely seen mangrove keystone species. The tall mud mounds they create are the result of processing huge amount of mud to obtain the organic material the lobsters feed on. The mounds will eventually become a key habitat for several mangrove animals like tree-climbing crabs, other invertebrates and even certain species of mangrove snakes.

I did a search on ScienceDirect and a surprising paper from 1942 turned up. It was written by researchers in Singapore recommending the use of lime and water to kill mud lobsters!! Their aim was to control the proliferation of mud lobster mounds thus eradicating breeding sites of malaria mosquitoes. Boy, am I glad our researchers have moved on from this mindset.

There are two species of Mud Lobster in Singapore. What we saw is most probably a Thalassina anomala. But the taxonomy of Thalassina genus is difficult and needs to be revised.

Pictures and video taken at: Mangrove in western Singapore, January 2007.

References:

Holthuis, L. B., Marine Lobsters of the World.
http://ip30.eti.uva.nl/BIS/lobsters.php?selected=beschrijving&menuentry=soorten&id=12

Ng, P. K. L. & N. Sivasothi, 1999. A Guide to the Mangroves of Singapore II, Singapore Science Centre, Singapore.

Scharff, J. W. & M. W. F. Tweedie, 1942. ‘Malaria and the Mud Lobster’, Transactions of the Royal Society of Tropical Medicine and Hygiene, vol. 36 (1), pp. 41-44.

Leaf Slug

2007-01-24T01:20:00.000+08:00

Over the past weekend, Chek Jawa and reportedly Beting Bronok suffered mass deaths of intertidal creatures. I was at Chek Jawa with Team Seagrass last weekend and it was indeed a sad sight. There were many dead and dying carpet anemones and sea cucumbers. The smell of decomposition lingered in the air and the slight drizzle did little to cheer the mood.

As the field orientation proceeded, one of the volunteers spotted two little leaf slugs. I smiled. Amid the gloom and doom, the leaf slugs are still surviving. Chek Jawa is not dead and will remain alive as long as we protect it.

This leaf slug is an Elysia species. Leaf slugs feed mainly on algae and appear green because of the presence of chloroplasts in their digestive system. These creatures have evolved a symbiotic relationship with algal chloroplasts which they suck directly when feeding on algae. The fascinating leaf slugs can then use the ingested chloroplasts to feed themselves photoautotrophically. Some scientists have even referred them as solar-powered!

This leaf slug is an Elysia ornata from St. John’s Island. It is one of the most beautiful fauna we can meet on our intertidal shores.

Pictures taken at: Chek Jawa, January 2007 and St. John’s Island, December 2006.

References:

Colin, P. L. & C. Arneson, 1995. Tropical Pacific Invertebrates. A Field Guide to the Marine Invertebrates Occurring on Tropical Pacific Coral Reefs, Seagrass Beds and Mangroves, Coral Reef Press, U.S.A.

Rumpho, M. E., E. J. Summer & J. R. Manhart, 2000. ‘Solar-Powered Sea Slugs. Mollusc/Algal Chloropast Symbiosis’, Plant Physiology, vol. 123, pp. 29-38.

Black-headed Munia

2007-01-14T15:32:00.000+08:00

We went on a birding trip to Marina East a few weeks ago. As usual, it was a great learning experience with GD in our group. One of the birds we saw was the Black-headed Munia (Lonchura malacca) also known as the Chestnut Munia.

Munias belong to the family Estrildinae. These birds have a small rounded body and a conical bill that is well suited in handling their main diet, seeds. Adult Black-headed Munias are easily recognized by their chestnut plumage and a black hooded head. In Singapore, they are commonly encountered in grassland habitat and areas of secondary growth and cultivation. They are usually seen in groups as they fly and forage from one area to another over open country, reminding me of an air raiding gang of hooded robbers.

The excellent Bird Ecology Study Group blog has a very interesting posting on tailless Black-headed Munias.

Picture taken at: Marina East, January 2007.

References:

Davison, G.W.H. & Y. F. Chew, 1995. A Photographic Guide to Birds of Peninsular Malaysia and Singapore, New Holland Publishers (UK) Ltd, London.

Robson, C., 2000. A Field Guide to the Birds of South-east Asia, New Holland Publishers (UK) Ltd, London.

Singapore Fishing Spider

2007-01-14T02:30:00.000+08:00

The Singapore Fishing Spider (Thalassius albocinctus) belongs to the family Pisauridae. This family of spiders is also known as the nursery-web spiders. Females would carry their large egg sac in their chelicerae and could be seen wandering about on tip toes. Before hatching, they will place their egg sac in a silken tent and stay guard outside.

T. albocinctus inhabits near water in mangroves and forest streams where it could dive to catch small fishes before dragging its prey ashore. Till recently, T. albocinctus is known only from Peninsular Malaysia, Singapore and Sulawesi.

The species diversity of spiders is just mind-boggling. They have evolved to occupy all sorts of ecological niches and many of them have fascinating hunting techniques. I’ve always been captivated by spiders and the Spiderman comics. My recent spidering trips with Joseph Koh have given me new found respect for these little predators.

Pictures taken at: Sungei Buloh Wetland Reserve, August 2006

References:

Koh, K. H. J., 1989. A Guide to Common Singapore Spiders. Singapore Science Centre.

Murphy, F. & J. Murphy, 2000. An Introduction to the Spiders of South East Asia, Malaysian Nature Society. United Selangor Press Sdn. Bhd, Kuala Lumpur.

Blue-spotted Mudskipper

2007-01-09T15:52:00.000+08:00

Blue-spotted Mudskippers (Boleophthalmus boddarti) are commonly encountered on the mudflats in our mangrove habitats. At low tides, they could be seen moving their head from side to side. This allows them to skim a thin layer of algae from the mud surface. They are mainly herbivorous, feeding on algae and fungal material. Small invertebrates also form part of their diet.

Blue-spotted Mudskippers have great affinity to water and are less adapted to terrestrial breathing than other mudskipper species. This is why they are found near water and will periodically enter the water to wet their gills as shown in the picture. They retreat into their burrows at high tides.

I am amazed by their vigorous display patterns of erected dorsal fins that looked like sails and the bright blue spots on their body. They are certainly one of the more conspicuously coloured mudskipper species in Singapore.

Pictures taken at: Khatib Bongsu, April 2006 and Sarimbun Mangrove, January 2007

References:

Ip, Y. K., S. F. Chew, L. L. Lim & W. P. Low, 1990. ‘The Mudskipper’, in Essays In Zoology. Papers Commemorating the 40th Anniversary of the Department of Zoology, National University of Singapore, eds, L. M. Chou & P. K. L. Ng, Department of Zoology, National University of Singapore.

Larson, H. K. & K. K. P. Lim, 2005. A Guide to Gobies of Singapore. Singapore Science Centre.