Black Widow Spider
Description - Adult female body legth about 1/2", abdomen
almost spherical. Black with two reddish triangular markings usually
joined to form a reddish hourglass-shaped marking on the abdomen.
Habits - Commonly live among and under stones and pieces of
wood, in hollow stumps and trees, rodent burrows, sometimes in
shrubbery. Prefer dry man-made structures including barns, outhouses,
sheds, meter boxes, brick veneer, barrels, woodpiles, foundations, etc.
If they are found indoors they are in seldom used parts of garages,
basements, and crawlspaces.
Lifespan/Reproduction - Eggs are about 3/8-1/2" in diameter and
can be constructed in 1-3 hours. Females can lay from 6 to 21 sacs in a
lifetime with about 185-464 eggs per case. Incubation period ranges
from 8 to 30 days. Take nearly a year to mature from egg to adult and
females can live for approximately 2 years. Spin irregular webs and
females generally avoid light and is normally shy and retiring.
Problems Encountered - Females have venomous bites (a
neurotoxin). Female will aggressively attack after egg laying and when
guarding her eggs. Bites cause slight local swelling with 2 tiny red
spots where the fangs entered. Pain is almost immediate and reaches its
maximum in 1-3 hours continuing for 12-48 hours. May experience
increased body temperature and blood pressure, sweting and nausea. is
rarely fatal except occasionally in small children and those with
Tips for Prevention - Building should be in good condition, well
sealed and screened. Outdoor lighting should be away from the building
or yellow/sodium vapor lamps. Keep premises free of debris that would
Preparation - Follow tips for prevention. Be prepared to leave the structure being treated for several hours.