Spider Wars: Brown Widows Annihilate Black Widows From Florida To California

Many people strongly dislike spiders. The red-hourglass family is particularly feared and distrusted. Now comes word that brown widows annihilate black widows in much of the country.

They are cousins, of course, and members of the family Latrodectus. Latrodectus is from the Greek and means biting in secret. There are about 30 species in the nasty family. They are found in most of the world. Five are found in the United States. Three are black widow varieties one is red and one is the brown widow. The red widow has dangerous venom but is restricted in range to palmetto scrub in Peninsular Florida. It rarely is encountered by people. It may be expanding its range.

Black Widow with egg sac
Black Widow with egg sac by Insects Unlocked Project is licensed under CC-CC0 1.0 Brown widows tend to annihilate their cousins

The other two are found in much of the United States and are vying for control. The brown widows appear to be winning. The conflict was noted as early as 2019. What is new is the discovery that the brown widows apparently seek out and destroy the black widows. They are far more tolerant of other spider species in their neighborhood.

Why is not clear. What is clear is that the brown widows have several advantages. They are fertile earlier and more fertile. Brown widows apparently can tell when a black widow is nearby and make positive efforts to hunt it. They appear to be driving the black spiders out of city regions and into the country where they do better than the brown widows.

A brown widow, latrodectus geometricus

This may be good news for people. Both spiders produce highly toxic venom. The venom is a potent neurotoxin, said to be many times more powerful than rattlesnake venom. But the brown widows are even more shy of people than the black widows. Neither likes to inhabit houses. Both widows tend to be found in woodpiles, under structures and in dark rarely accessed areas. Brown widow venom may be much more toxic than black widow venom. But the spiders inject smaller amounts and are believed to be much less aggressive toward people. Either way serious complications are very rare. Medical treatment and anti-venin have reduced deaths. According to one source 1,000 people were bitten in 2018, None died but six had life-threatening signs. The last reported widow bite death in the United States may be as far back as 1983.

A red widow, latrodectus bishopi. This one has an almost heart-shaped mark on its back. They also lack a complete hourgkass on the belly.

Of course the entertainment industry has stoked fear of the spiders. There are many examples. In 1936 The Ex-Mrs Bradford featured murder by black widow. An ingenious killer managed to place a (probably very angry) widow inside a gelatin capsule. He then palmed the capsule onto the victim. When the gelatin melted – Instant Death!

In the 1950’s American radio featured the very popular Yours Truly, Johnny Dollar.

That program aired an episode with an equally unlikely scenario. A mad researcher used dozens of black widows as security guards. The spiders were alleged to be in a safe guarding important papers. A burglar put a hand in the safe – Instant Death!

The danger of widow spidrs is real. But it shouldn’t be exaggerated. There are more dangerous spiders in the world.

The brown widows apparently came to the United States around 1935 from South Africa or South America. They probably arrived in product shipments. Other invasive spiders include the harmless to humans joro spiders. The discovery of widow-to-widow predation is raising other questions. One is whether this behavior is localized to the United States or exists in other ranges the two spiders share.

Published by ursusrising

long time writer and editor living in Los Angeles

Leave a Reply

%d bloggers like this: