The Brown Widow Is Commonly Encountered Within Homes And Buildings In Southern Texas, But This Exotic Species Is Rapidly Expanding Northward
According to the Centers for Disease Control and Prevention, the only two spiders in North America that inflict medically harmful and potentially fatal venomous bites include the black widow and the brown recluse. These two spiders are prevalent throughout Texas, and both are synanthropic species that establish indoor populations that can become extensive. An indoor presence of black widows or brown recluse spiders should be considered a medical hazard deserving of professional pest control intervention. While these two spiders are responsible for the vast majority of medically significant spider envenomation incidents reported to poison control centers annually in the US, they have relatives in the country that are just as dangerous.
Of the three black widow spider species that inhabit the US, only the southern black widow (Latrodectus mactans) can be found in Texas. This species is responsible for the greatest number of black widow envenomation incidents reported annually, and most of these incidents occur in Texas. In addition to the southern black widow, a closely related species that is native to Africa was introduced into the US several decades ago, and they have been significantly expanding their habitat range in Texas and other Gulf Coast states in recent years, possibly due to climate change. This species is commonly known as the brown widow (L. geometricus), and its appearance is similar to that of the southern black widow.
The brown widow’s venom is twice as potent as the venom produced by black widows, which is really saying something considering that the latter’s venom is 15 times more potent than rattlesnake venom. However, the brown widow injects a smaller amount of neurotoxin than the black widow, which makes the former far less dangerous than their native relatives. The brown widow is commonly encountered within both homes and commercial buildings in southern Texas, and studies have found that the species is migrating northward at a significant pace.
Have you ever spotted a black widow in your home?