Seed caching and cache pilferage by three rodent species in a temperate forest in the Xiaoxinganling Mountains

Although differences in food-hoarding tactics both reflect a behavioral response to cache pilferage among rodent species and may help explain their coexistence,differentiation in cache pilfering abilities among sympatric rodents with different hoarding strategies is seldom addressed.We carried out semi-natural enclosure experiments to investigate seed hoarding tactics among three sympatric rodent species(Tamias sibiricus,Apodemus peninsulae and Clethrionomys rufocanus)and the relationship of their pilfering abilities at the inter-and intraspecific levels.Our results showed that T.sibiricus exhibited a relatively stronger pilfering ability than A.peninsulae and C.rufocanus,as indicated by its higher recovery rate of artificial caches.Meanwhile A.peninsulae showed a medium pilfering ability and C.rufocanus displayed the lowest ability.We also noted that both cache size and cache depth significantly affected cache recovery in all three species.T.sibiricus scatter-hoarded more seeds than it larder-hoarded,A.peninsulae larder-hoarded more than scatter-hoarded,and C.rufocanus acted as a pure larder-hoarder.In T.sibiricus,individuals with lower pilfering abilities tended to scatter hoard seeds,indicating an intraspecific variation in hoarding propensity.Collectively,these results indicated that sympatric rodent species seem to deploy different food hoarding tactics that allow their coexistence in the temperate forests,suggesting a strong connection between hoarding strategy and pilfering ability.

Seed caching and cache pilferage by three rodent species in a temperate forest in the Xiaoxinganling Mountains

Although differences in food-hoarding tactics both reflect a behavioral response to cache pilferage among rodent species and may help explain their coexistence, differentiation in cache pilfering abilities among sympatric rodents with different hoarding strategies is seldom addressed. We carried out semi-natural enclosure experiments to investigate seed hoarding tactics among three sympatric rodent species (Tamias sibiricus, Apodemus peninsulae and Clethrionomys rufocanus) and the relationship of their pilfering abilities at the inter- and intraspecific levels. Our results showed that T. sibiricus exhibited a relatively stronger pilfering ability than A. peninsulae and C. rufocanus, as indicated by its higher recovery rate of artificial caches. Meanwhile A. peninsulae showed a medium pilfering ability and C. rufocanus displayed the lowest ability. We also noted that both cache size and cache depth significantly affected cache recovery in all three species. T. sibiricus scatter-hoarded more seeds than it larder-hoarded, A. peninsulae larder-hoarded more than scatter-hoarded, and C. rufocanus acted as a pure larder-hoarder. In T. sibiricus, individuals with lower pilfering abilities tended to scatter hoard seeds, indicating an intraspecific variation in hoarding propensity. Collectively, these results indicated that sympatric rodent species seem to deploy different food hoarding tactics that allow their coexistence in the temperate forests, suggesting a strong connection between hoarding strategy and pilfering ability.

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

Superior species may have distinct advantages over subordinates within asymmetrical interactions among sympatric animals.However,exactly how the subordinate species coexists with superior species is unknown.In the forests west of Beijing City,intense asymmetrical interactions of food competition exist among granivorous rodents(e.g.Apodemus peninsulae,Niviventer confucianus,Sciurotamias davidianus and Tscherskia triton)that have broadly overlapping habitats and diets but have varied body size(range 15-300 g),hoarding habits(scatter vs larder)and/or daily rhythm(diurnal vs nocturnal).The smallest rodent,A.peninsulae,which typically faces high competitive pressure from larger rodents,is an ideal model to explore how subordinate species coexist with superior species.Under semi-natural enclosure conditions,we tested responses of seed-hoarding behavior in A.peninsulae to intraspecific and interspecific competitors in the situations of pre-competition(without competitor),competition(with competitor)and post-competition(competitor removed).The results showed that for A.peninsulae,the intensity of larder-hoarding increased and the intensity of scatter-hoarding declined in the presence of intraspecifics and S.davidianus,whereas A.peninsulae ceased foraging and hoarding in the presence of N.confucianus and T.triton.A.peninsulae reduced intensity of hoarding outside the nest and moved more seeds into the nest for larder-hoarding under competition from intraspecific individuals and S.davidianus.In most cases,the experimental animals could recover to their original state of pre-competition when competitors were removed.These results suggest that subordinate species contextually regulate their food-hoarding strategies according to different competitors,promoting species coexistence among sympatric animals that have asymmetrical food competition.