Contiguous Allotopy of Pardosa ramulosa and Pardosa tuoba (Araneae: Lycosidae) in the San Francisco Bay Region, and Its Implications for Patterns of Resource Partitioning in the Genus

Abstract

Two Pardosa spp. are contiguously allotopic in the San Francisco Bay region, with P. tuoba restricted to coastal prairie and coastal scrub habitats and P. ramulosa inhabiting adjacent salt marshes as well as the borders of bodies of standing fresh water within the habitat of P. tuoba. P. ramulosa may be a specialist on open water habitats, where it feeds preferentially on insects of the surface film. Coexistence in these 2 spp., and in other sets of sympatric Pardosa spp., was made possible by partitioning of the array of essentially 2-dimensional habitats with low-growing vegetation.