Reciprocal pilfering in a seed-caching rodent community: implications for species coexistence

摘要

Cache pilfering rates have been reported to be unsustainably high in many seed-caching rodent communities, but the dynamics of pilfering is largely unknown at the community level. In this study, we examined rates of seed-cache pilfering in a species-rich community of granivorous rodents in pair-wise trials. We compared the ability of each species to pilfer from conspecifics as well as heterospecifics to determine if pilfering is symmetrical or asymmetrical in the community. During the study, pilfering was more or less symmetrical among three scatter-hoarding species of rodents, averaging 28% (SD = 26%) of caches pilfered in 24 h, while the lone larderhoarding species was unable to pilfer and experienced cache loss at the rate of 16 +/- 14% of caches in 24 h to the other species. Pilfering was reciprocal among the scatter-hoarding species among conspecifics and heterospecifics despite differences in caching behavior (cache depth, size, and location). These finding support the hypothesis of reciprocal pilfering and are consistent with theories of the coexistence of ecologically similar species by lessening the effects of competition among species at the resource level and demonstrate that species with a pilfering disadvantage may need to exhibit