Surface Soil Type Preference for Burrowing of the Endangered and Endemic Trapdoor Spider Calathotarsus simoni (Araneae: Migidae)

Abstract

Calathotarsus simoni Schiapelli & Gerschman, 1975 is an endemic and rare trapdoor spider that lives exclusively in the mountainous systems of southern Buenos Aires province, central Argentina. In previous studies, authors suggested the preference of this species to a particular soil surface type. Thus, we hypothesized that this species differs in its responses to the soil surface type for burrow construction. To test this, we placed 26 adult females in chambers providing two choices (soil with moss and without moss) and compared the proportions of observations in each to evaluate species preference. Calathotarsus simoni significantly preferred the soil with moss. We observed a remarkable behaviour before the construction of the burrow when spiders were at the soil with moss. Finally, we discuss the possible ecological significances of this preference.