The Star, Malaysia : Langkawi

Tuesday, May 06, 2003

Langkawi : Dragonflies

THEY may be delicately pretty, but dragonflies can be hardy insects too. For some vague reasons, some species choose to live only in foul, stagnant pools. This habit, nevertheless, comes in handy – it can be used to indicate the quality of a particular habitat.

Odonatologist Dr Y. Norma-Rashid of Universiti Malaya who works on dragonflies says because different species of dragonflies prefer different kinds of habitat, their presence or absence reflect the health of that habitat – hence they are useful “bio-indicators.”

“If we find certain species gone, it serves as an early warning sign that something is wrong. Some species live only amongst certain vegetation, such as bamboo groves or ginger plants. The sudden disappearance of these species may mean that habitat is damaged or is no longer healthy,” she explains.

Odonatologist Dr. Y. Norma-Rashid of Universiti Malaya who works on dragonflies says some species live only amongst certain vegetation such as bamboo groves or ginger plants. The sudden disappearance of these species may mean that habitat is damaged or no longer healthy.

This is evident from the associate professor’s survey along Sungai Kisap in Langkawi. As the stream courses through developed sites such as durian orchards, rubber estates, a golf course and then a village, she netted dragonflies which are associated with polluted sites. “At the village, the river is very dirty, with algae blooms. We get species found in stagnant water.”

Norma says growing interests in dragonflies is not purely aesthetics but because of their many applications, one of which is as “bio-control” agents. As dragonfly larvae feed on mosquito larvae, they help keep the pesky insect at bay.

Peninsular Malaysia boasts of 220 species of dragonflies. Norma says many new records had surfaced in the past two years as work intensified. The dragonfly species of Langkawi have never been documented. Norma’s short survey found nothing new but one species stood out: the rare Megalogomphus sumatranus which she had collected previously in the forest of Gua Musang, Kelantan.

“It is not fair to rank the richness of dragonflies in Langkawi since I collected only over three days and in a few rivers. I expected the species here to be different, but so far I have found species which are similar to the mainland’s.”

During the expedition, Norma also surveyed mudskippers with post-graduate student Khaironizam Md Zain.

In several streams in Langkawi, she found seven of the 13 species which she had recorded for the mainland. “This is good as it is half of the mainland species,” she says.

More interesting, however, is that a new species which she recently found in Kuala Selangor, the Periopthalmus bucephalus, was also caught in two Langkawi rivers.