Katydid Asiophlugis species

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)

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

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

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.