Tidhar Wendy L, Bonier Frances, Speakman John R
Aberdeen Centre for Energy Regulation and Obesity (ACERO), School of Biological Sciences, University of Aberdeen, Aberdeen AB14 2TZ, Scotland, UK.
Horm Behav. 2007 Nov;52(4):436-44. doi: 10.1016/j.yhbeh.2007.06.009. Epub 2007 Jun 30.
Increased perception of predation risk can cause changes in activity, feeding and reproductive behavior in a wide range of taxa. Many small mammals in the temperate zone exhibit fluctuations in body mass in response to changing photoperiod. Bank voles lose body mass in winter which they regain when photoperiod increases in the spring. To determine if predation risk affects seasonal changes in body mass (BM), bank voles were exposed to two concentrations (low: LC and high: HC) of weasel feces. Food intake (FI) and daily energy expenditure (DEE) were measured to establish if differences in body mass were due to adjustment in energy intake or expenditure. Fecal corticosterone (CORT) was measured to assess whether the voles had detected and responded to predator feces as a physiological stressor. Voles of both sexes had higher levels of fecal CORT in the groups exposed to weasel feces compared to controls. Voles responded to the predator feces in a sex- and concentration-dependent manner. Males responded to LC feces by gaining less mass following the change in photoperiod. This was mediated by reduced FI and higher DEE. Female voles also gained less BM in response to HC feces, but increased both FI and DEE. We hypothesize that males may gain a short-term advantage by lowering BM in response to predation risk, which may be regained without affecting reproductive success. The consequences of mass loss in females may be more significant as this may delay the onset of breeding or reduce the size or number of young, thereby negatively affecting breeding success.
对捕食风险的感知增加会导致广泛类群的活动、觅食和繁殖行为发生变化。温带地区的许多小型哺乳动物会随着光周期的变化而出现体重波动。棕背䶄在冬季体重减轻，春季光周期增加时体重又会恢复。为了确定捕食风险是否会影响体重（BM）的季节性变化，将棕背䶄暴露于两种浓度（低：LC和高：HC）的黄鼬粪便中。测量食物摄入量（FI）和每日能量消耗（DEE），以确定体重差异是否是由于能量摄入或消耗的调整所致。测量粪便皮质酮（CORT），以评估田鼠是否将捕食者粪便作为一种生理应激源进行了检测并做出了反应。与对照组相比，暴露于黄鼬粪便的两组雌雄田鼠的粪便CORT水平都更高。田鼠对捕食者粪便的反应具有性别和浓度依赖性。雄性对LC粪便的反应是在光周期变化后体重增加较少。这是由FI减少和DEE增加介导的。雌性田鼠对HC粪便的反应也是体重增加较少，但FI和DEE都增加。我们假设，雄性可能通过降低体重以应对捕食风险而获得短期优势，这种优势可能在不影响繁殖成功的情况下恢复。雌性体重减轻的后果可能更严重，因为这可能会延迟繁殖开始或减少幼崽的大小或数量，从而对繁殖成功产生负面影响。
