A comparative study of caching and pilfering behavior in two sympatric species, least chipmunks (Tamias minimus) and eastern chipmunks (Tamias striatus).

Abstract

We captured least chipmunks (Tamias minimus) and eastern chipmunks (T. striatus) from overlapping populations and assessed their comparative success at heterospecific pilfering in a naturalistic laboratory setting. The smaller species (T. minimus) found their competitors' caches more quickly and with less effort. We traced the success of least chipmunks to foraging behavior that targeted the vulnerabilities of eastern chipmunk caches, and a cache placement counterstrategy that protected their own food stores. The value of pilfered caches for least chipmunks was magnified by their smaller body size and the bigger cache size of their larger competitor. We suggest that heterospecific cache pilferage represents an especially lucrative foraging tactic for small foragers.

Context‐dependent responses of food‐hoarding to competitors in Apodemus peninsulae: implications for coexistence among asymmetrical species

“…In addition, our results suggest that there were definitely asymmetrical interactions in food competition between sympatric species that have similar ecological niches, supported by several previous studies that were conducted under enclosure conditions and in the field (e.g. Penner & Devenport 2011;Zhang et al 2014b;Dittel et al 2017;Gu et al 2017). For example, N. confucianus (large-size) harvested more seeds from the seed station than A. peninsulae (small-size), and showed a unidirectional pilferage of seeds cached by A. peninsulae (Zhang et al 2014b).…”

“…These strategies are not mutually exclusive and are context-dependent for a given species. While comprehensive, most of the above responses and adaptations have been described from patterns of intraspecific competition/pilferage, and more research is needed to study food competition between interspecific hoarders (but see Leaver & Daly 2001;Thayer & Vander Wall 2005;Vander Wall et al 2009;Penner & Devenport 2011;Zhang et al 2013b;Dittel et al 2017).…”

“…Interactions in food-hoarding between sympatric rodents are associated with species coexistence (Leaver & Daly 2001;Price & Mittler 2003Vander Wall et al 2009;Penner & Devenport 2011;Luo et al 2014;Dittel et al 2017;Gu et al 2017;Wang et al 2018). Due to differential capabilities of food competition (e.g.…”

“…Due to differential capabilities of food competition (e.g. body size), sympatric species usually exhibit asymmetrical interactions in that some species (superior species hereafter) may have distinct advantages over others (subordinate species hereafter) Penner & Devenport 2011;Zhang et al 2014b;Dittel et al 2017). Asymmetrical competition in food-hoarding and pilferage has been observed to occur between intraspecific individuals that have different social statuses (e.g.…”

“…Zhang et al 2011;Huang et al 2019) and sympatric species that have different body sizes, hoarding habits, daily rhythms and/or diets (e.g. Vander Penner & Devenport 2011;Zhang et al 2014b;Dittel et al 2017;Gu et al 2017). In the case of asymmetrical interactions, context-dependent regulation of hoarding strategy is critically important for survival of the subordinate species that endures heavy cache losses, and coexistence of sympatric species that share similar habitats and diets.…”