Leaf Slug

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

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

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

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.