Dunn Jonathon, Andrews Clare, Nettle Daniel, Bateson Melissa
Centre for Behaviour and Evolution, Institute of Neuroscience, Newcastle University, Newcastle, UK.
R Soc Open Sci. 2018 May 9;5(5):171918. doi: 10.1098/rsos.171918. eCollection 2018 May.
Animals require strategies for coping with periods when food is scarce. Such strategies include storing fat as a buffer, and defending the rate of energy intake by changing foraging behaviour when food becomes difficult to obtain. Storage and behavioural defence may constitute alternative strategies for solving the same problem. We would thus expect any developmental influences that limit fat storage in adulthood to also induce a compensatory alteration in adult foraging behaviour, specifically when food is hard to obtain. In a cohort of hand-reared European starlings, we found that higher manipulated early-life begging effort caused individuals to maintain consistently lower adult body mass over a period of two years. Using an operant foraging task in which we systematically varied the costs of obtaining food, we show that higher early-life begging effort also caused stronger behavioural defence of the rate of energy intake when food was more costly to obtain. Among individuals with the same developmental history, however, those individuals who defended their rate of energy intake most strongly were also the heaviest. Our results are relevant to understanding why there are marked differences in body weight and foraging behaviour even among individuals inhabiting the same environment.
动物需要应对食物短缺时期的策略。这些策略包括储存脂肪作为缓冲，并在食物难以获取时通过改变觅食行为来维持能量摄入率。储存和行为防御可能是解决同一问题的替代策略。因此，我们预期任何限制成年期脂肪储存的发育影响也会导致成年觅食行为的代偿性改变，特别是在食物难以获取时。在一组人工饲养的欧洲椋鸟中，我们发现幼年时期更高的乞食努力导致个体在两年时间内成年体重持续较低。通过一项操作性觅食任务，我们系统地改变获取食物的成本，结果表明幼年时期更高的乞食努力还会在食物获取成本更高时导致对能量摄入率更强的行为防御。然而，在具有相同发育史的个体中，那些对能量摄入率防御最强的个体也是体重最重的。我们的研究结果有助于理解为什么即使在栖息于相同环境的个体之间，体重和觅食行为也存在显著差异。
