The brown recluse spider has become notorious for inflicting bite wounds that sometimes develop tissue-necrosis. This medically significant spider species has established habitats within 15 states in the midwest and the mid-south. While the brown recluse is widely considered to be one of only two medically significant spider species in the US, several other recluse species have been documented as inflicting medically significant bites in the US as well.

The United States is home to 11 recluse species, all of which are distributed throughout the lower half of the country. However, the brown recluse has appeared within several northern states, such as New York, Pennsylvania, Wyoming and Massachusetts, due to this spider’s habit of hitchhiking to new regions within plant materials. Although many sources claim that recluse habitats are limited to the southern half of the US, one particular species, the Mediterranean recluse, has established habitats within several northeast states. This species has been spotted numerous times within New York City and Boston, which is not surprising to experts since research shows that the Mediterranean recluse adapts to new regions more readily and with greater success than all other recluse species in the entire world. This species has also been documented as inflicting bites to humans that develop necrotic infections.

The Mediterranean recluse is native to Europe, but this species has established isolated habitats in the northeast US. For example, Mediterranean recluse spiders have been infesting steam pipes at Pennsylvania State University for years now. Luckily, no students, teachers or staff members have been reported as sustaining a bite from the Mediterranean recluse. Bites from the Mediterranean recluse are not as dangerous as brown recluse bites, but several case reports have described necrotic bite wounds that had been inflicted by the Mediterranean recluse. The first documented death resulting from a Mediterranean recluse bite occurred three years ago, but this species is not considered a serious threat to humans, as most bite wounds heal on their own with no medical intervention.

Have you ever spotted a spider that you believed was a recluse species?