Plant structure specialization in Paraphidippus basalis (Araneae: Salticidae), a jumping spider of the Madrean Sky Islands

Abstract

Paraphidippus basalis (Banks, 1904) is a large jumping spider that occurs in the sky islands of the southwestern United States and northern Mexico. To date, P. basalis has only been incidentally reported on rosette-forming plants in the family Asparagaceae (yucca, agave, and sotol), even though the sky islands support a rich and diverse vegetation community. This apparent specialization is unusual because jumping spiders do not typically have strong associations with the plants on which they live. However, given that the ecology of P. basalis has yet to be studied, the microhabitat preferences of P. basalis remain unclear. We investigated microhabitat choice in P. basalis in the Patagonia Mountains of southeastern Arizona, to determine whether these spiders were specifically associated with rosette-forming plants. We surveyed 160 plots for jumping spiders, 80 with rosette-forming plants and 80 without. P. basalis was found only in rosette-forming plants, whereas other species of jumping spiders showed no preference for rosette or control plots. Larger rosette plants were more likely to contain P. basalis. This study provides an unusual example of host plant structural specificity in a jumping spider.