Brown Widow Spider Creeps into SD

Species may outnumber black widow, study says

By Lauren Steussy
|  Tuesday, Jul 3, 2012  |  Updated 8:05 AM PDT
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The brown widow spider (right) next to its more infamous counterpart the black widow spider.

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There's a new spider in town, and it may be taking over San Diego's population of black widow spiders, one southern California study claims.

The brown widow spider shares the same red hour-glass figure as its sinister sister, the black widow. But brown widows are less poisonous and slightly smaller than black widows, according to the UC Riverside study in this month's Journal of Entomology.

The brown widow has only been in southern California since 2003. Since then, their populations have grown, and they have now been found in more places than black widow spiders.

It's sometimes hard to distinguish between the two types of spiders, but more often than not, if you find a widow spider in common household places, it's a brown window spider, the study found.

Here's a guide to telling the difference between the two.

"If they are displacing black widows, overall widow envenomation risk may actually be lower than before brown widow establishment," wrote the study's authors.

This could mean fewer bites as San Diegans dust off their patio furniture for the Fourth of July celebrations.

The study found spiders in 72 locations around southern California. In order of prevalence, the spiders were found in the following places:

  • Under picnic and patio tables
  • Under patio chairs
  • Under support beams of wooden fences
  • Playground equipment
  • Garbage bin handles
  • Curled lips of potted plants

In places where brown widows were found, such as these locations, there were far fewer black widows, the authors wrote. 

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