ST. PETERSBURG, Fla. — The U.S. National Weather Service in the Tampa Bay area spotted what seemed like a black widow, only for it to turn out to be a brown widow.
How were they able to tell the difference? By the spiny-shaped egg sacs located inside the web, NWS said in its Facebook post.
Brown widows are an invasive species in the Tampa Bay area. It's believed they are native to southern Africa, but now they can be found in Hawaii, Florida, some Caribbean Islands and parts of Africa, according to a report by the Center for Invasive Species Research Mission.
Brown and black widow spiders are just two of the four species of widow spiders in Florida — all venomous. The southern black widow and the red widow can also be found in parts of the Sunshine State. Black widows are believed to be native to North America and also closely related to the western black widow.
Another interesting find was that brown widows are seeking out and killing their black widow relatives, a study by the University of South Florida found. In a contained habitat, USF researchers found that brown widows were 6.6 times more likely to attack black widows than other related species. They believe the behavior is a likely force behind the black widow spider's population decline.
"Though the study characterizes brown widow spiders as aggressive toward black widows, that isn’t the case when it pertains to humans," researchers with USF report. "Brown widow venom causes less severe reactions to humans than black widows, and bites to people are very rare."
However, it's said that brown widow spiders are mildly venomous and black widow spiders are extremely venomous.
When spotting the difference between brown and black widows, there are a few ways to differentiate between them. Brown widows live in open areas while black widows hide in dark corners and crevices. Their color can also be a dead giveaway. Brown widows are shades of brown with stripes along the sides and top of their abdomen while black widows are shiny black in color with a red or orange dot on top of their abdomen.
