Wednesday, 28 December 2011

NSS Kids’ Fun with Dragons and Damsels

By Gloria Seow, Education Group Chairperson

The dragonfly and damselfly world is populated by mystifying characters with names such as Treehugger, Telephone Sylvan and Crimson Dropwing. These names remain perplexing until one discovers that they perfectly describe the unique characteristics of particular Odonata (dragonfly) species. We learnt that the Treehugger (Tyriobapta torrida) is almost always found resting on tree trunks; the Telephone Sylvan (Coeliccia octogesima) has a pair of blue markings on its upper thorax that resemble the handles of telephones; and the Crimson Dropwing (Trithemis aurora) has the habit of gradually folding its wings downward when it lands.

Telephone Sylvan has a pair of blue markings on its upper thorax that resemble the handles of telephones.

Not only did we get close-up views of our three protagonists, the kids were also entertained by a supporting cast of 13 winged wonders on 13 August 2011 at the sparkling Venus Drive stream. We had the pleasure of being guided by four dragonfly enthusiasts: Tang Hung Bun, Dr Cheong Loong Fah, Robin Ngiam and Cheong Yi Wei.

The excitement began within metres of the Venus Drive car park. Here, the stream appeared inconspicuous, partially hidden by overgrown grass. This did not deter our guides. They gamely descended its steep slopes to point out the various delicate creatures that abounded around its clear waters. We gasped at the size of one of Singapore’s tiniest damselfly, the Variable Wisp (Agriocnemis femina), which measured just 2 cm from head to tail.

Auntie Gloria helping to show kids a forest dragonfly.

As expected, dragonflies were relatively difficult to tell apart. Many of the common ones were mostly red or mostly blue. Uncle Tang, who is also the author of the book “A Photographic Guide to the Dragonflies of Singapore”, brought along his brilliantly-photographed guidebook to help us identify the creatures.

On average, dragonflies spend about six months of their lives residing as larvae at the bottom of streams and stagnant waters. They feed on tadpoles, small fishes, water beetles, fleas and mosquito larvae, amongst other things. They can even turn cannibalistic if food is scarce. Like butterflies, they undergo metamorphosis, transforming from swimming juveniles into flying adults. After this, they only live on for one to two more months. This is just enough time to find a mate and perpetuate the next generation.

As adults, dragonflies are top predators in the insect world. They hunt down pesky mosquitoes, small butterflies, spiders and damselflies. There is even a record of a dragonfly killing a hummingbird in the US. Singapore has at least three Odonata species that are migratory, invading our air space in large numbers during the monsoon months. In the US, certain dragonflies are fondly called mosquito hawks.

Uncle Loong Fah pointing out the dragons and damsels of Venus Drive Stream.

We followed the stream from the sunny grassland into the gloom of the forest. Here, we saw a different cast of dragonflies from the open country variety. Instead of congregating around water, the forest dwelling ones are more isolated and less conspicuous. This gives the impression that there are fewer species living here, although it is not true. Both the Telephone Sylvan and Treehugger are forest varieties. We also located the uncommon and beautiful Blue sided Satinwing (Euphaea impar) after some hard searching. Altogether, it was a fruitful morning with most of us experiencing dragonfly watching for the first time. Indeed, the insect world is far more deserving of our attention given its tremendous diversity and beauty.

No comments: