Mary V. Price, Nickolas M. Waser, and Shauna McDonald.
2000. Seed caching by heteromyid rodents from two communities: implications
for coexistence. Journal of Mammalogy 81:97-106.
Abstract. The diversity of species in communities
of heteromyid rodents presents a classic problem to ecologists, because
species are similar ecologically and share a limiting seed resource. Mechanisms
of coexistence considered to date have focused on interspecific variation
in ability to exploit heterogeneity in resources caused by environmental
factors. An unexplored possibility is that coexistence is promoted by heterogeneity
among species in seed-caching behavior. To begin evaluating this possibility,
we asked whether coexisting species differ in their propensity to cache
and in types of caches made. In an indoor arena, we presented millet seeds
to eight species of kangaroo rats (Dipodomys) and pocket mice (Perognathus
and Chaetodipus) from two communities, one in California and one
in Arizona. Species within communities differed in amounts of seed consumed
and cached per night. Both consumption and caching increased with body
mass in a manner similar to whole-animal metabolic rate, suggesting that
energetics underlie food-storage behaviors. Species also differed significantly
in propensity to cache in the home burrow (larderhoard) versus in small
depots outside the burrow (scatterhoard); scatterhoarding increased with
body mass. Kangaroo rats scatterhoarded proportionally more than sympatric
pocket mice, and species from California tended to scatterhoard more than
those of similar body size from Arizona. These interspecific differences
are consistent with the possibility that caching promotes coexistence.
Our results appear to contradict those from a similar study of heteromyid
caching behavior that used a different protocol for presenting seeds. This
discrepancy underscores the importance of understanding the extent to which
caching behavior is sensitive to details of experimental protocol or animal
state and of moving experimental caching studies into more natural situations.