Ceriagrion cerinorubellum

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)

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

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

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

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.