Venomous Black Widow Spiders were found in the Southampton area and residents are urged to be extremely cautious.

Until Monday, there have been no sightings of these poisonous arachnids, however two were found in a South Whale Estate, Southampton residence.

In the past the spiders have occasionally been found in containers and in shipments of fruit but are usually found and destroyed before they have a chance to escape into the wild.

This most recent sightings of the spiders has led Government entomologist Claire Jessey to believe there is a breeding population.

She said: "There is every reason to be concerned. [People needed to be] vigilant, aware and extremely cautious."

The Department of Environmental Protection is working with the Department of Environmental Health and a local pest control company to eradicate any threats in the Southampton area where the spiders were found.

Surveys and searches of nearby structures and businesses will be carried out to determine the extent of the infestation.

Brown widow spiders have been on the island for many years but are a less aggressive species than the black widow and their bite is not as painful or dangerous.

Spiders can be sprayed with household insecticide but under no circumstances should live spiders be collected or handled. A professional pest control company can also be contacted to destroy any black widow spiders.

Poisonous adult female black widow spiders can be identified by their shiny, jet black, spherical abdomen with two connected red triangles on the underside that form a characteristic hourglass marking.

The hourglass colour may range from yellowish to various shades of orange or red. Adult females are about a half of an inch long, without their legs and one and a half inches when their legs are spread. Adult males are harmless and are about half the female's size, with smaller bodies and longer legs.

Black widow spiders have potent neurotoxic venom and are considered the most venomous spider in North America.

However, the female dosage injected is so small that it rarely causes death. Less than one percent of people have died from black widow spider bites.

A bite from a black widow spider may go unnoticed initially. At first, there may be slight local swelling and two faint red spots, which are puncture points from the fangs.

Pain soon begins and usually progresses from the bite site to finally localise in the abdomen and back. Severe cramping or rigidity may occur in the abdominal muscles.

Other symptoms may include nausea, profuse perspiration, tremors, laboured breathing, restlessness, increased blood pressure, and fever.

Symptoms often diminish after a day or so and cease after several days. Serious long-term complications or death are very rare.

These spiders usually are found outside in dry man-made structures such as garages, sheds and meter boxes.

If bitten by a black widow spider, immediately seek medical attention and apply an ice pack to the bite area to relieve swelling and pain.

Collect the spider (even a mangled specimen has diagnostic value), if possible, for positive identification by a spider expert. A plastic bag, small jar, or pill vial is useful and no preservative is necessary.

For more information or if anyone believes they see a black widow spider they should immediately contact the Department of Environmental Protection, Plant Protection Office on 239 2311 or the main department line at 236 4201.