Symbiotic Relationships Between Pseudoscorpions (Arachnida) and Packrats (Rodentia)‪.‬

ABSTRACT. Thirty-two species of pseudoscorpions have been found co-existing with nine packrat (or wondrat) species of the genus Neotoma, and this association has been referred to as phoresy. Phoresy is a term for passive dispersal when an animal literally hitches a ride on another to reach a new habitat. The pseudoscorpions reported above live in or on the nests of the packrats and do not ride on the rats themselves, eliminating a truly phoretic association. All life-history stages of the small arachnids have been found in packrat nests, indicating at least a commensalistic relationship exists, whereby the pseudoscorpion benefits from shelter and food found in the nests, and reproduces there as well. Two pseudoscorpion species have been reported feeding on packrat ectoparasites, specifically larval and adult fleas, and thus a mutualistic relationship beneficial to both "guest" and "host" exists. Keywords: Packrats, Neotoma, phoresy, commensalism, mutualism