Arachnids: The Recluse Spiders

Insects are everywhere. I try not to dwell on the idea that insects are crawling on everything all the time, but entomologists seem to love the fact that there are of multitudes of insects everywhere we go. That's probably why I'm not a entomologist. Still, insects are a vital part of life, and I am interested in learning more about them.

Mediterranean recluse. Photo by Antonio Serrano

This past week I attended The New York Entomological Society’s meeting on arachnids. Biologist James Beck came up from Louisiana to The American Museum of Natural History in NYC to talk about a specific genus of arachnids the Loxosceles, commonly known as recluse spiders. James Beck studies the ranges of two species of recluse, the native brown recluse (Loxosceles reclusa) and the invasive Mediterranean recluse (Loxosceles rufescens).

Recluses aren’t rare, but the public knows very little about these spiders except the fact that they are venomous. At the lecture I learned that people, even doctors treating spider bites, tend to think every spider that isn’t a widow is a recluse. James Beck told us that misidentification of recluses went so far in a nationwide survey conducted in 2005 that people asked to send in specimens of brown recluse didn’t send in a single one. The public did send many other spider species, and even a scorpion, but no brown recluses.

I’ll admit that I would probably not be able to tell the difference between a brown recluse and a Mediterranean recluse if I saw either one. I don’t think I would mistake a scorpion for a spider like someone in the study did, but identifying Loxosceles is not an easy feat, as James Beck explained. Brown recluse and Mediterranean recluse can be distinguished by their tibial segments (a part of the leg) and mouthparts, both of which require magnification to see. Different recluse species don’t like to live side by side, so if a Mediterranean recluse is identified, there shouldn’t be any brown recluse around.

Knowing the difference between the two types of recluse might be tricky, but identifying the general genus Loxosceles isn’t as hard. Loxosceles are terrestrial spiders that like to live in places like crowded sheds and basements.

Brown Recluse Photo by Rosa Pineda

Don’t worry about finding a recluse if you don’t want to. They are named “recluse” for a reason, and Loxosceles are timid spiders. They rarely bite unless provoked and aren’t at all interested in harming humans. Spiders get a bad rap for being venomous and aggressive, but in reality they are helpful creatures that kill pests like cockroaches. To avoid being bitten, if you see a spider on you, don’t smack it, gently put it down. Try to bring out that bug loving entomologist we all have within us and both you and the spider will come out happier.

 photo of a live brown recluse from the lecture