Biodiv Sci ›› 2007, Vol. 15 ›› Issue (4): 329-336.DOI: 10.1360/biodiv.070004

• 论文 •     Next Articles

Key factors affecting the capacity of David’s rock squirrels (Sciurotamias davidianus) to discover scatter-hoarded seeds in enclosures

Hongmao Zhang 1,2,3, Zhibin Zhang 1*   

  1. 1 State Key Laboratory of Integrated Management of Pest Insects and Rodents in Agriculture, Institute of Zoology, the Chinese Academy of Sciences, Beijing 100101
    2 College of Fisheries, Huazhong Agricultural University, Wuhan 430070
    3 Graduate University of the Chinese Academy of Sciences, Beijing 100049
  • Received:2007-01-09 Revised:2007-06-13 Online:2007-07-20 Published:2007-07-20

Abstract: Olfaction, vision, random search and spatial memory have been suggested to be important factors for hoarders to rediscover hoarded foods, but whether they work differently on different species is not clear. In this study, we studied the role of olfaction, vision, random search and spatial memory on seed discovery capacity of David’s rock squirrels (Sciurotamias davidianus) in enclosures in the Dongling Mountain, north-western Beijing, China. We decreased the olfactory signal of the experimental seeds (cultivated walnut, Jug-lans regia) by sealing with plastic bags, and blocked the visual signal by burying the seeds in soil. We com-pared seed discovery rates of the following four treatments: (1) On ground (G): seeds placed on ground sur-face; (2) Buried (B): seeds buried in soil; (3) Sealed & placed on ground (S & G): seeds placed on ground surface sealed in plastic bags; and (4) Sealed & buried (S & B): seeds buried in soil sealed in plastic bags. We also compared seed discovery rates when S. davidianus discovered seeds buried by themselves (Self-Buried, S-B) and by other individuals (Other-Buried, O-B). The ranking of the seed discovery rates of the four treatments were B (Mean±SD: 59.5±27.6 %) > G (53.3±27.7 %) > S & B (31.0±27.2 %) > S & G (26.3±28.6 %); Seed discovery rates of B and G treatments (Z=–0.356, P=0.722), and of S & B and S & G treatments (Z=–0.493, P=0.622) were not significantly different. This suggests that the seed discovery ca-pacity of S. davidianus was not significantly affected by blocking the visual signal. Seed discovery rates of G was significantly higher than S & G (Z=–2.084, P=0.037), and B was significantly higher than S & B (Z=–2.943, P=0.003). This suggests that the seed discovery capacity of S. davidianus was significantly de-creased when olfactory signal of seeds was decreased. When seeds were both sealed and buried (S & B), 31.0 % buried seeds were discovered, which suggests that S. davidianus could discover some seeds with random search. Moreover, seed discovery rates of S-B (57.9±21.8%) and O-B (54.4±33.9%) were not significantly different, which suggests that an individual S. davidianus has no advantage in discovering seeds buried itself, as if there was no effect of spatial memory. These results suggest that olfaction is the key factor for S. david-ianus to rediscover hoarded seeds, secondarily relying on random search. Vision and spatial memory seem to play a less important role.