Archive for the ‘Latrodectus geometricus’ tag

the hitchhiker   15 comments

Posted at 8:07 am in spiders

As you might guess, each day is now crammed with many errands and odd jobs as I move the last of my belongings into storage, clean up the house and yard, and marshal all of our gear for the autumn-winter trip. A couple of days ago, while my mom was out for a visit, I was showing her some feature on the back of my van. I happened to notice some webbing around the trailer hitch and decided to pull the plastic cover cap off of the square hitch opening. As I pulled at the cap, there was a surprising amount of tension and it was then that I noticed a stretchy piece of webbing with a couple of moths dangling from it. Being quite familiar with spider webs, the amount of tension in the web threads struck me as odd and unfamiliar, and then I thought of how messy the webbing around the hitch looked — and that immediately set me to wondering if there was some species of Widow (Latrodectus) spider lurking about.

The webbing snapped and I inspected the inside the plastic cover in my hand. Indeed, there was the spider, hanging prettily in a bit of webbing on the inside of the cap. I noticed she wasn’t quite as dark as the other Widow spiders that I’ve seen. This one was dark brown with curving lateral lines, with the typically bright reddish-orange hourglass pattern on the underside of the abdomen. Her long, hackled legs were a two-tone brown.

As most of you know, I’m not much for killing spiders — basically, I’m pretty much a live and let live person and only occasionally collect invertebrate specimens if asked to by a biologist friend. However, I decided that releasing this non-native spider would be rather irresponsible even if she couldn’t tough out our winter, so I dropped her into a vial of alcohol and will pass her along to someone who can make use of the specimen for a collection.

This morning, I did a bit of looking around online, and it seems as though this spider might be a Brown Widow (Latrodectus geometricus), commonly found in Florida – which is where my van came from back in May. So, my hitchhiking spider must have come up to Canada inside the trailer hitch opening. When I extracted the webbing inside the hitch, I found at least two or three exuviae tangled up with a variety of dead insects, so she appears to have done remarkably well stowed away beneath the van. In this factsheet from the Univ. of Florida, Sarasota, Dr. Fred Santana writes of the distribution of the Brown Widow:

Since this article was first written in 2000, this spider has spread throughout Florida and people have reported sightings of it from Southern California, Colorado, Texas, Arkansas, Mississippi, Alabama, Georgia, and South Carolina. Complaints about its occurrence in cars and RVs indicate this spider will make it home in these sites. Cars, trucks, and RVs have probably helped to distribute this spider far and wide. Its rapid expansion in Florida in the late 90s may have been the result of the milder winters. However, the most important factor in its expansion has probably been transportation by vehicles. The Extension Office continues to receive complaints asking how to rid them from in and under cars.

Sounds pretty much like this spider’s modus operandi. No doubt, our winter would have finished her off, but it’s easy to see how such spiders can easily hitchhike their way all around North America.

Written by bev on August 25th, 2009

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