Subject: Black Widow Spiders
Geographic location of the bug: Northern New Mexico
Date: 10/04/2017
Time: 12:05 AM EDT
Good evening.
I moved to Santa Fe from Southern Oregon four months ago for work and I have never encountered female black widow spiders like this. We have killed eight large, female specimens in the house over the past two days. Most of them were on the move in broad daylight, and surprisingly aggressive. Two of them were actively sharing a web. I captured one in my bathroom, and confirmed the red hour glass. I’ve never known female widows to act like this, unless defending egg sacks. Is this a sub species native to New Mexico, or some sort of infestation I was previously unaware of?
How you want your letter signed: Alexa Rense
Dear Alexa,
According to BugGuide: “The Latrodectus genus breaks down taxonomically into approximately 31 recognized species, five (5) of which are found in the United States; four (4) species are native, one (1) species (L. geometricus) was introduced.” According to BugGuide data, it is the Western Black Widow that is found in both Oregon and New Mexico. While the bite of a Western Black Widow can be dangerous, they are not an aggressive species, though many female spiders will defend eggs and young. We are lamenting the loss of native Western Black Widows in Los Angeles where they seem to have been entirely replaced in recent years by the invasive Brown Widow.
I’m in Tampa, Florida and out of the many dozens of brown widows I found in the backyard last year, only one was a black widow.
Introduced, Invasive Exotic species like the Brown Widow can often have a negative impact on populations of native species.