31 March 2010

Wildfacts updates: February and March

It's been a 'dry' period as there were not many low spring tides in February and virtually none in March. So it's a good time to catch up on fact sheets on old sightings.
The visit by Dr Fujita, the brittle star expert, was a good excuse to do up a fact sheet on this commensal brittle star (Ophiomaza cacaotica) that lives in a feather star! We saw it once at Raffles Lighthouse many years ago.

It was also wonderful that Siyang and his team identified the little purple sea cucumbers that we often see under stones on some of our rocky shores. It is Afrocucumis africana, so I thought a more appropriate common name would be the "Little African sea cucumber"!
I also learnt from his paper that these sea cucumbers multiply by fission, i.e., by dividing into pieces. Which is why sometimes we see lots of little ones huddled under a stone! It also has the habit of 'carrying' bits and pieces, possibly as camouflage.

A first time sighting: this miniature sea hare, Aplysia parvula. It is among the smallest of the Aplysia sea hares, and 'parvus' means 'little'. But it isn't the smallest sea hare I've seen: the seagrass seahare (Phyllaplysia sp.) is much smaller.
Thanks to a kind comment from a reader, I also discover the identity of this strange snail. An empty shell was seen at Tuas. Kok Sheng found another empty shell at Tanah Merah. So far, we've not seen a live one, yet.
It is the Sunburst carrier-shell snail (Stellaria solaris). It belongs to the Family Xenophoridae which are called carrier shell snails because they cement bits of shells onto their own shell. The living snail has a very long proboscis with which it uses to attach these bits onto its own shell. See a photo of a snail doing this. But the our carrier snail rarely sticks objects to the shell, except on early whorls.

It seems a good time to do up some fact sheets on our figs! Figs are fascinating because of their unique flowering structure and intriguing relationship with the tiny fig-wasps that pollinate them.
Before the fig becomes a real 'fruit', it is actually an inside-out flower! At first, little round things develop on the tree. These are not (yet) fruits but a fleshy, hollow structure with tiny flowers inside the hollow. This is why we refer to these structures as figs, and we say the tree is 'figging'. After the tiny hidden flowers are fertilised and develop seeds, the fig becomes a compound fruit. That is, all the tiny fertilised fig 'fruits' are fused together. Like in a strawberry or pineapple. But turned inside out!

A beautiful but rare fig is the Collared fig (Ficus crassiramea) (left photo), with one lovely tree at Pulau Ubin near the Ubin Jetty. This fig is listed as 'Critically Endangered' in Singapore.
A large and striking fig that I also saw at Pulau Ubin is the India-rubber tree (Ficus elastica) with bright red stipules (the 'wrapped up' new leaf at the tip of the branch). Before the introduction of Hevea brasiliensis, the India-rubber tree was a major source of rubber in our part of the world.

Some figs are stranglers! They begin life as a small plant (from seeds dropped by a bird or climbing animal), high up on a tall host tree. The young fig sends down long roots. When the roots reach the ground, they thicken and encircle the host tree. By shading out and preventing the host tree from thickening its trunk, the now rapidly growing fig eventually 'strangles' and kills the host tree.

The Waringin (Ficus benjamina) (left photo) is a very common strangling fig sometimes seen growing on old crumbly buildings. It can become an enormous tree! Its small leaves have elegant pointed tips.
The Jejawi (Ficus microcarpa) is also common, and has small, blunt leaves. There is a magnificent specimen next to the Tower at the Chek Jawa boardwalk. When this tree is figging, an amazing variety of creatures are attracted to the feast and we can spend hours just looking at the party in the tree!

The Common red stem-fig (Ficus variegata) has floppy heart-shaped leaves and its figs are found in bunches encrusting the trunk and thick branches!
I can't wait to learn more about figs at the upcoming Leafmonkey Workshop for nature guides. Join the facebook page or subscribe to the blog to get updates!

Morning low spring tides begin again over the Easter weekend! Can't wait to get those booties properly wet!

I'd gladly include your sightings in the wild fact sheets. Just email me, Ria at hello@wildsingapore.com.

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