|
Five species of venomous spiders occur in Florida:
the southern black widow, northern black widow, red
widow, brown widow and brown recluse.
The four species of widow spiders are very similar
in body shape. All are about 1-1/2'' long with legs
extended. Their life cycle is also similar. The female
lays about 250 eggs in a pear-shaped egg sac that is
about 1/2'' to 5/8'' in diameter. The eggs hatch in about 20
days. As the young spiders mature, they construct a
loosely woven web and capture progressively larger
prey. In Florida, all the widows except the northern
black widow breed year-round.
Anyone bitten by a spider should preserve it in
rubbing alcohol for positive identification. Most spider bites are not considered dangerous, but if you
suspect one of the widow or brown recluse spiders, get
medical attention immediately.
Southern black widow. This is the most wide-spread widow spider in Florida. It is glossy black and
has a complete hourglass marking on the underside of
the abdomen. The northern black widow has the same
general appearance. but has two red triangles resembling an hourglass and a row of red spots on top of the
abdomen. The northern species is found west of Tallahassee, primarily in forests, with its webs three to 20
feet above the ground. The southern black widow is
usually found outdoors in protected places, such as
under rocks and boards, and in and around old buildings. The bite of the black widow and other widow
spiders usually feels like a pin prick. The initial pain
disappears rapidly, leaving local swelling and two tiny
red marks. Muscular cramps in the shoulder, thigh and
back usually begin within 15 minutes to three hours. In
severe cases, pain spreads to the abdomen, the blood
pressure rises, and there is nausea, sweating and difficulty in breathing. Death may result, depending on the
victim's physical condition, age and location of bite. Death seldom occurs if a physician is consulted and
treatment is prompt.
Red widow. This species has attack abdomen and
reddish-orange head, thorax and legs. The top of the
abdomen usually has a row of red spots with yellow
borders. This spider lacks a complete hourglass on the
underside of the abdomen and instead usually has one
or two small red macks. The red widow constructs its
web in palmettos and has been found primarily in sand-
pine scrub habitats in central and southeast Florida.
Brown widow. This spider varies from light-gray
to light-brown to black. The abdomen has variable
markings of black, white, red and yellow. The underside of the abdomen has an orange or yellow hourglass.
It is found most often south of Daytona Beach along the
coast. It usually makes its web on buildings in well-lighted areas.
Brown recluse. This is not an established species
in Florida. It is recognized by the distinctive dark
violin-shaped mark located on the head and thorax.
The brown recluse is a medium-sized spider about 1/4''
to 1/2', long. It is light-tan to deep-reddish-brown. It is
usually found in sheds, garages or areas of homes that
are undisturbed and contain a supply of insects to serve
as food. Favorite hiding places include arms and legs of
garments left hanging for some time or beds that have
been unoccupied for long periods of time. Persons
bitten by this spider usually do not feel pain for two to
three hours. A blister arises at the site of the bite,
followed by inflammation. Eventually the tissue dies,
leaving a sunken sore. Healing may take as long as six
to eight weeks.
Pest ID Library Source Data: Cooperative Extension Service, University of Florida, Gainesville, Institute of Food and Agricultural Sciences |
