Black widows
can be
found throughout Arkansas. The body of the female is usually shiny and
black and can be up to 1½” long, including the legs. The
abdomen
appears fat and nearly spherical and it may bear few or many reddish
spots.
The most characteristic spot occurs on the underside of the abdomen,
and
it is usually somewhat hourglass-shaped. Males are much smaller
and
narrower than females, and they have white lines on the abdomen in
addition
to red markings. Classification and identification of black
widows
is notoriously difficult. There is so much variation and overlap
in characters that it is not always possible to name a given specimen
with
certainty. It is now understood that at least 2 species occur in
Arkansas.
   Black widows build irregular webs of coarse silk, usually near the ground in dark places, and usually outdoors. Webs are often built among leaf litter on the ground in deciduous forests. They are also found under rocks or logs, in piles of rubble, in mammal burrows, and in dark corners of sheds, garages, crawl spaces, cellars, and basements. The spiders hang in an inverted position in these webs, do not leave them voluntarily, and are clumsy and completely out of their element away from them. They will eat almost any insect that wanders into the snare. In one study of southern black widows in Texas cotton fields, three quarters of the spiders’ prey consisted of fire ants (Nyffeler et al. 1988)
Although the nocturnal black widows are not aggressive, females will bite when provoked sufficiently. Males, which are rarely seen, do not bite. Females may rush out and bite when their webs are disturbed or when they are accidentally touched or trapped in clothing or shoes. In the past, bites were most commonly inflicted on people using outdoor privies. Today people are most likely to suffer black widow bites while moving lumber or other clutter from infested areas, while sitting on outdoor furniture, or when putting on clothing in which a spider is trapped. The venom of the black widow is and oily yellow fluid that causes a general release of neurotransmitters at synaptic junctions, and so the clinical manifestations of a black widow bite are primarily neurological. The insertion of the female's fangs produces mild to sharp pain. Tissue reactions at the site of the bite are minimal, but they may include redness, mild swelling, and itching. Within 30 to 60 minutes, the victim experiences severe pain in local muscle groups. Pain migrates from the site of bite to regional muscle groups. Severe cramps may spread throughout the body. In a typical case, the victim will experience unremitting, cramping pain of extremities, thorax, back, abdomen, and groin areas. Pain and cramping peaks at 2 to 3 hours and may debilitate the victim for 24 to 36 hours. Other symptoms include hypertension, profuse perspiration, nausea, fatigue, shock, and coma. Severe cramping of abdominal and thoracic musculature can lead to respiratory distress, which may be fatal. Death has been reported in less then 1% of documented black widow spider bite cases. Healthy individuals usually recover quickly and completely (Blackman 1995, Kunkel 1984, Wilson and King 1990) First aid for black widow bites consists of cleaning the wound thoroughly and applying ice packs to slow absorption of the venom. Over-the-counter pain relievers may be used to relieve minor symptoms. The victim should be taken to a physician or hospital immediately. The physician will treat for pain and cramping with intravenous calcium and muscle relaxants. An antivenin is available for serious cases. To reduce the occurrence of black widow spiders, rubble, scrap, lumber, disused machinery, and similar items should be removed from yards. Take proper precautions, wear gloves, and pay attention to where you are working or relaxing. Inspect outdoor furniture before sitting. Insecticides labeled for spider control can be applied around buildings and in crawl spaces to reduce spider populations. Spraying near the ground, in cracks and crevices, around windows or doors will significantly reduce spider populations and reduce the number of insects that are available as food sources |
Mating
most often occurs in late spring and early summer. Although
hungry
females may kill their mates, some healthy males live to mate with
several
females (Breene and Sweet 1985). Females can produce several egg
masses during a summer. Egg sacs made of tough, papery, tan or
gray
silk are suspended in the snare. They are a little less than half
and inch in diameter. Those of the southern black widow are
spherical
and have a conspicuous nipple at the top. Those of the northern
black
widow are more pear-shaped. Young spiderlings are much lighter in
color than adults, adding more black with each molt. Half grown
females
resemble full-grown males. Spiderlings mature in 2 to 3
months.
Females often live more than one year, and some have been known to live
as long as three years (Kaston 1970).