Research on spider diversity (the number of spider species) in Ohio has been limited. The first major effort was conducted by William M. Barrows (1883-1946) of the Ohio State University, culminating in publications from 1918 to 1924.  Barrows listed 306 species of spiders known from Ohio at that time.

Between 1924 and the beginning of the Ohio Spider Survey, several published projects as well as unpublished masters’ theses and PhD dissertations increased our known list up to 410 species.  The work of the Ohio Spider Survey (1994-2014) increased the list of species known from our state to 682 species.  Of course this doesn’t mean that several hundred spider species have recently moved into Ohio, it is merely an increase in our knowledge about our spider fauna.  There have been a few species “introduced” by the actions of humans, mostly through accidental importation with stored materials, garden and landscape shipments, and incidental transport into Ohio. Some have established populations here. These number about 12 species (there is debate about the status of a few of these).

There are quite a few species which have not been detected recently.  Examining the verified records (supported by a voucher specimen), 104 species have not been recorded since 1994. Many of these species are small, inconspicuous, or difficult to find.  Some may have disappeared from the state, but it seems likely that others have just gone undetected.

A current project involves the identification of specimens held in the Ohio Spider Collection, housed at the Museum of Biological Diversity of the Ohio State University, Columbus, Ohio. This work is attempting to examine, identify, and catalog, a large backlog of unidentified specimens there. Many of these were collected by researchers doing other field work, and captured spiders by accident (bycatch). Others were donated by spider researchers. As a result of this work, the list of species known from Ohio has increased to 700 species.

Tod and Suzan Jervey working on curation of the spider collection

Lauren Blyth working on curation of the spider collection

The current check-list is available here.

I thank Suzan & Tod Jervey, Lauren Blyth for their many hours of volunteer curatorial work. I also thank Mark Milne (Indianapolis University) Mike Draney (University of Wisconsin, Green Bay) and Nina Sandlin (Field Museum) for their help with the challenging identification of dwarf sheetweb weavers (Linyphiidae, Erigoninae).