Alien spider species spotted

A brown widow spider belonging to the widow spider group was spotted at Thiruvalla recently.
It was an adult female spider. The spider collected by Manoj Thomas, a medical practitioner, was identified by Samson Davis and P.A. Sebastian, of the Spider Lab of the Sacred Heart College, Thevara.The specimen is being kept at the lab of the college. The creature might have been accidentally introduced to the State and more research needs to be carried on the species, said Mr. Davis, who is also the head of the Zoology Department of the College.Widow spiders are highly poisonous and the black widow spiders found in North America and West Indies are poisonous enough to kill human beings. Though the poison of the brown widow is supposed to be more toxic than that of the black widow, the dose of poison it can inject at a time is very little and has only localised action. The brown spider is not very aggressive, does not defend its web and bites are not common. Hence, one need not be afraid of this spider, said Mr. Davis. The colour intensity of brown widows ranges from light tan to dark brown.They may also have a red broken stripe or a series of white spots along the top of the abdomen with parallel rows of black spots on either side of the stripe.There is an orange hourglass mark on the underside of the abdomen. The head is usually dark brown. Legs are usually tanned and black banded, Mr. Davis said.The spider lab of the college focuses mainly on taxonomical studies and also bio-control of agricultural pests.

The Hindu, 29th October 2009