THE EFFECT OF BODY CONDITION ON THE TRADE-OFF BETWEEN VIGILANCE AND FORAGING IN BELDING GROUND-SQUIRRELS
THE EFFECT OF BODY CONDITION ON THE TRADE-OFF BETWEEN VIGILANCE AND FORAGING IN BELDING GROUND-SQUIRRELS
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DOI：
10.1006/anbe.1993.1185
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发表时间：
1993-08-01
期刊：
影响因子：
2.5
通讯作者：
BACHMAN, GC
中科院分区：
文献类型：
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作者：
BACHMAN, GC
通过田间试验研究了能量储备变化对觅食和捕食者警戒之间权衡的影响。对自由生活的雌性黄鼠幼仔进行了三步实验。首先，松鼠的行为反应，以磁带记录同种报警电话进行了观察（回放1）。然后，在6天的时间内，无论是自由觅食补充能量丰富的食物（花生酱混合物），或觅食的机会被限制了几个小时，每天，在此期间，能量贫乏的食物（生菜）。这两种治疗分别导致体重增加（“补充”组）或中度体重减轻（“剥夺”组）。最后，观察到松鼠对第二次报警呼叫的反应（回放2）。在回放2，剥夺个人不太警惕，觅食比补充个人。在回放2，警惕性呈正相关，觅食呈负相关，以衡量身体状况和治疗过程中的质量变化。前一周的身体状况和质量变化不是独立的，因此很难确定哪一个对觅食活动的影响更大。然而，在播放2后的一周内，当所有松鼠都自由觅食时，剥夺组的质量增加率高于补充组。这些结果表明，（1）觅食与警惕的决定是受身体质量偏离“设定点”，（2）适度减少能量储存可以影响觅食和警惕之间的权衡，即使没有短期的能量短缺的威胁。
A field experiment was performed to examine the effect of a change in energy reserves on the trade-off between foraging and predator vigilance. Free-living juvenile female Belding's ground squirrels,Spermophilus beldingi, were observed in three-step experiment. First, a squirrel's behavioural response to a tape-recorded conspecific alarm call was observed (playback 1). Then, over a 6-day period, either ad libitum foraging was supplemented with an energy-rich food (peanut butter mixture), or foraging opportunities were restricted for a few hours every day, during which an energy-poor food (lettuce) was available. These two treatments resulted in weight gain ('supplemented' group) or moderate weight loss ('deprived' group), respectively. Finally, a squirrel's response to a second alarm call was observed (playback 2). During playback 2, deprived individuals were less vigilant and foraged more than supplemented individuals. At playback 2, vigilance was positively related and foraging was negatively related both to a measure of body condition and to the mass change during treatment. Body condition and mass change during the previous week were not independent, making it difficult to determine which had a greater impact on foraging activity. However, in the week after playback 2, when all squirrels were foraging freely, the deprived group showed a greater rate of mass gain than the supplemented group. These results suggest that (1) the foraging versus vigilance decision is affected by body mass deviations from a 'set-point', and (2) a moderate reduction in energy stores can influence the trade-off between foraging and vigilance even though there is no short-term threat of energetic shortfall.