Black Widow Spiders – Latrodectus hesperus
The female black widow spider is considered the most venomous spider in North America. The venom of the black widow spider is 15 times as toxic as the venom of the prairie rattlesnake.
Only the female black widow is dangerous to humans; males and juveniles are harmless. The female black widow will, on occasion, kill and eat the male after mating. More than 35,000 species of spiders occur worldwide. About 3,400 species of spiders in 64 families are found in North America.
Female black widow spiders are about 5 inch long, to about 1.5 inches long when the legs are spread.
Males are about half the female’s size, with smaller bodies and longer legs.
Both females and males have shiny, globular abdomens and are mostly black, and sometimes brown.
Females usually have a reddish hourglass shape on the underside of their abdomens. In some species the females have a series of red spots and two crosswise bars on the underbelly.
Male black widows frequently have yellow and red bands and spots over their backs, as do both sexes of black widows in their immature stages.
Newly hatched spiderlings are predominately white or yellowish-white, gradually acquiring more black and varying amounts of red and white with each molt.
Juveniles of both sexes resemble the male and are harmless to humans.
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