Friday, October 08, 2010

Back Guiding at Chek Jawa

It's been a while since I last went to help out at Chek Jawa, so I was quite glad that I finally managed to find time to do so.

When I reached the Ubin Volunteers' Hub, I was surprised to see the area next to the hub covered with Rattlebox plants (Crotalaria sp.). Guess that shows I really have not been here for a while. And on the flowers, I found a number of these pretty moths.

I have not seen these kind of day-flying moths before. Two of them here.

And here are three of them. Didn't realised the plants were Rattlebox plants until KS Wong told me. The usual ones I saw came with compound leaves with three leaflets. Apparently there were quite a few species of Rattlebox plants in Singapore.

There were a few Pea Blue (Lampides boeticus) butterflies resting on the Rattlebox plant, which was supposed to be their host plant. I saw a number of caterpillars feeding on the leaves, which I assumed should be Pea Blue caterpillars.

There were also a few Blue Glassy Tiger (Ideopsis vulgaris macrina).

Soon, all the volunteers arrived, and we made our way to Chek Jawa.

And greeting us was the resident Wild Boar (Sus scrofa).

Thanks to Terry, who decided to guide on my behalf, I got to do hunting-seeking, something which I have not done for quite sometime at Chek Jawa. While heading to the intertidal area, I noticed that the Mata Ayam (Ardisia elliptica) were fruiting! "Mata" means "eye" and "ayam" means "chicken", and this plant was so named supposedly because the fruits appeared like chicken eyes.

The first animal I spotted was this female Flower Crab (Portunus pelagicus) among the seagrass. Seagrass meadows are very important habitats for many marine animals, many of which can be eaten by human, such as this Flower Crab. This crab is a type of swimming crab, characterised by the paddle-like back legs, which allow them to swim rather quickly.

Also in the seagrass meadow, I found this Crenate Swimming Crab (Thalamita crenata). Related to the flower crab, it also has paddle-like back legs, and is also edible. I have seen fishermen collecting them when I was in Bali. It was quite aggressive, and kept flashing its claws whenever I got near to it.

But the top swimming crab I found must be this Orange Mud Crab (Scylla olivacea) that was initially half-buried in the sand in the seagrass meadow. It was humongous! I found two of them but only took one to show the visitors.

So I guess you can imagine that without seagrass meadows, many of the seafood we love will be gone too.

While seeking for interesting animals, I came across this Orange Striped Hermit Crab (Clibanarius infraspinatus), which has climbed out of its shell. Not sure why it climbed out of the shell though. Unlike true crabs which have a hard exoskeleton all over, hermit crabs have a soft abdomen and hence they hide in the shells of dead snails, such as the Noble Volute above, for protection.

Here's a living Noble Volute (Cymbiola nobilis). Found 3 of them during this trip. This huge snail hunts for other smaller snails or clams to feed on. They will wrap their muscular foot around the prey to attempt to suffocate them. When the snail or clam emerge to breathe, the volute will feed on them.

Yet another predator of smaller snails and clams is this Pear-shaped Moon Snail (Polinices mammilla). Note only can it wrap its prey with its huge foot, it can also secrete an acid to soften the prey's shell, and using its radula (something like a tongue) to slowly create a hole through the shell to feed on the animals inside.

There were a few Haddon's Carpet Anemones (Stichodactyla haddoni) on the sand bar. This one was quite big, more than 30cm wide. Like other sea anemones, it uses its stinging tentacles to sting and capture prey.

It's definitely a Sandfish (Holothuria scabra) day, as I saw so many of them! This is the sea cucumber that we normally find in Chinese restaurants. Note that they must be properly treated by people who are trained to remove the toxins in them before they can be consumed.

We saw a few other types of sea cucumber, but one of the prettier ones must be this one which we called the Pink Thorny Sea Cucumbers (Colochirus quadrangularis). It's also seasonally abundant, and sometimes we can see hundreds of them!

As usual, there were lots of Sand Dollars (Arachnoides placenta) at the sand bank. They feed on tiny algae or other organic matter among the sand.

The only star of the day was the Sand Star (Astropecten sp.). It used to be very abundant here, but possibly because nowadays we are seeing less button shells and small clams here that they feed on, and hence their population here appeared to be going down as well.

After my hunting-seeking duties, I managed to run over to take a look at the Pemphis (Pemphis acidula), a mangrove plant that is critically endangered in Singapore.

Here's a look at both the fruits and the flowers. This plant is commonly used as a bonsai plant in the region, and in some places, are over-collected because of that. The seeds are dispersed by water.

Sure hope that I will soon see more of this plant around, since it appeared to be fruiting quite well! :)

1 comment:

Pat said...

The red-&-black spotted moth on the Crotolaria plants is Utetheisa pulchella (Crimson-Speckled Flunkey). In contrast to its colourful fore wings, the hind wings are plain white, with splotchy black margins.

The species originated from Africa, but now has a cosmopolitan distribution. Seems to be uncommon in S'pore at the moment. I guess it was probably imported along with the exotic butterfly-food plants used in local horticulture.