Bug of the Month
Venomous spider expert Philip C. Anderson once said, “in general, spiders attempt to avoid people. People should accommodate them.” Here’s one that everybody should accommodate.
The Southern black widow is one of the few spider species in Florida that’s venomous enough to warrant real caution from human beings.
Its scientific name, Latrodectus mactans, means “murderous biting robber,” so that’s a clue right there.
Both the females and males can deliver a potent bite, though the females are larger and thus carry more venom.
That venom contains several components that affect the nervous system, including something called latrotoxin, a toxic substance named for the widow genus, Latrodectus.
Children have been known to die from black widow bites, although healthy adults usually recover within a few days.
Fortunately, this species tends to live in places where humans seldom venture — cozy, quiet, dry areas like tool sheds, hollow stumps and wood piles. The other side of the coin is, when people DO venture into the black widow’s favorite haunts, they might not take steps to avoid the critters.
Those steps are pretty easy — wear gloves, examine items before picking them up, don’t put your hands into places you can’t see, and stay away from spider webs. (A female black widow guarding an egg sac in the nest is likely to defend it vigorously.)
We can all be thankful that indoor-plumbing technology has purged the Florida landscape of one of the most notorious locations for black widow bites, the old-fashioned outhouse.
Adult female Southern black widow spiders are glossy black, with an abdomen about the size of a pea. They can be recognized by the distinctive red hourglass mark on the underside of the abdomen. (Getting a look at the underside of the abdomen might not be so easy, and BugWeek@UF definitely does not recommend poking at suspected black widows to flip them over).
The adult males are smaller. They’re also glossy black and have a distinctive red-and-white pattern on their backs, as you can see in one of the photos posted here.
For the more timid among us, a good guideline is, steer clear of any smallish, glossy-black spiders found in out-of-the-way places.
Finally, if you have an alarming number of black widows on your property, it’s a good idea to have the situation checked by a pest-control professional. Treating black-widow infestations is not a learn-as-you-go kind of activity.
You can read more about the Southern black widow at this Featured Creatures document from the UF/IFAS entomology department.