Spider preying on Dragonfly.

The grass and reed beds by the sides of our inland reservoirs is a micro ecosystem by itself. It is teeming with insect life, mainly dragonflies, damselflies, grasshopper and some butterflies. I have been visiting the wetlands around our freshwater reservoirs mainly to photograph the odonatas.

Typical wetland habitat at our reservoirs.

Fong and his brother were photographing what looked like a Saint Andrew’s Cross Spider Argiope versicolor, wrapping up a motionless Common Scarlet dragonfly that got caught in its web.

The female St. Andrew’s Cross Spider wrapping up the Common Scarlet dragonfly.

All my past sightings of the St. Andrew’s Cross Spiders were by the forest edges and along the jungle trails in our nature reserves. This is the first time I seen it with its web across the long grasses by the water edge. How and why did this spider move out of the forest to a very different habitat was a puzzle to me. Could it be that there is a lack of insects or looking at a change of diet?

Another female just a meter away waiting to snare a dragonfly. The zigzag web is supposed to draw the prey to the web.

I did some checking in Biodiversity of Singapore and found that this is the Yellow-Silver St. Andrew’s Cross Spider, Argiope cantenulata, ( Marcus Ng), also known as a Grass Cross Spider. This orb-weaver spider is found from India to the Philippines and Papua New Guinea.

A helpless Common Scarlet falling victim to a smaller predator.

It preys mainly on dragonflies that hunt and breed in this habitat. Once it flew into its web, the spider quickly immobilizes it by spinning and wrapping the prey with its web. It then injects digestive enzymes into the victim to break down its body tissues. The spider sucks up the pre-digested tissues and repeats the process again. It seems to be locally common with most of the sightings along the edges of reservoirs. Apparently they are quite common in the padi fields in Malaysia.

Reference:

Biodiversity of Singapore.

Wikipedia.

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