In studies of refuge use as a form of antipredator behavior,where prey hide in response to a predator's approach, factorssuch as foraging costs and the perceived risk in a predator'sapproach have been shown to influence the hiding behavior ofprey. Because few studies of waiting games have focused on mammals,we studied the hiding behavior of the yellow-bellied marmot(Marmota flaviventris), a ground-dwelling rodent. We testedthe prediction that marmots vary hiding time as a function ofpredator approach speed and presence and absence of food outsidetheir refuge and that marmots hide differently depending ontheir relative condition. We conducted "fast approaches" and"slow approaches" in the presence and absence of extra foodand evaluated hiding times. Multiple regression analyses demonstratedthat the interaction between the approach speed and the presenceand absence of food influenced hiding behavior; body conditionhad a smaller, but nonsignificant effect. We then developeda state-dependent dynamic model to explore potential fitnessconsequences of these decisions. The model suggested that theoverall survival of a population is substantially reduced whenindividuals make suboptimal decisions. Our research builds onprevious studies, indicating that animals integrate both costsand benefits of hiding when determining their hiding times. 相似文献
Birds are capable of seeing the ultraviolet light (UV) spectrum and as a consequence have evolved UV‐reflective structures with signalling functions. Avian eggs also reflect in the UV spectrum but the importance of UV egg matching in egg rejection decisions has been equivocal. Here we conducted egg rejection experiments in the congeneric and sympatrically breeding Yellow‐bellied Prinia Prinia flaviventris and Plain Prinia Prinia inornata in Taiwan to assess the role of UV as a cue in egg discrimination. Yellow‐bellied Prinia is a host of Oriental Cuckoo Cuculus optatus, whereas Plain Prinia is not. We coated one prinia egg in the experimental clutches with a cream containing a UV‐blocking agent, while the rest of the eggs were coated with cream only. We also experimentally parasitized prinias with non‐mimetic model eggs with reduced UV reflectance. Yellow‐bellied Prinia and Plain Prinia rejected their own UV‐blocked eggs in 18.2 and 8.3% of the experiments, respectively, and the difference was not significant. However, Yellow‐bellied Prinia rejected 100% of the non‐mimetic eggs, whereas the Plain Prinia rejected only 5%. Hence, UV reflectance alone is a cue in egg discrimination, but the importance of reflectance outside the UV spectrum in these two prinia species is much more responsive to selection as a consequence of brood parasitism. 相似文献
1. 1.|A numerical, distributed parameter model of heat exchange is used to evaluate the thermal significance of the presence and placement of subcutaneous fat in hibernating marmots. The model is most sensitive to changes in conductivity and metabolic rate of muscle tissue, parameters which are known to greater precision than are others in the model.
2. 2.|Alternative models are developed for animals with fat located dorsally and with no fat at all.
3. 3.|A comparison of these three models shown that there is no difference in the metabolic output required to maintain body temperature among the three alternatives. Therefore, neither the presence nor the location of fat serves an insulative role in hibernators.
Author Keywords: Hibernation; insulation; body fat; thermal model; energetics; Marmota flaviventris; heat transfer 相似文献