Karpouzos Helen, Hernandez Alexandra M, MacDougall-Shackleton Elizabeth A, MacDougall-Shackleton Scott A
Department of Psychology, University of Western Ontario, London, Canada ON N6A 5C2.
Physiol Behav. 2005 Mar 16;84(3):465-9. doi: 10.1016/j.physbeh.2005.01.012.
Many animals seasonally change energy stores such as food caches and fat deposits. Two factors that potentially influence energy stores are changes in day-length and food availability. We investigated food storing and fat levels in black-capped chickadees to determine how they are affected by changes in duration of light period and duration of food availability. Because previous studies have confounded the effects of photoperiod and the effects of duration of access to food we manipulated these variables independently. Birds were exposed to either long days (15 h light with 15 h of food availability), long day light exposure with short day food availability (15 h light, 9 h food), or short days (9 h light, 9 h food). We measured mass, body fat and the number of sunflower seeds stored in 1-h test sessions for 2 weeks prior and 3 weeks following this manipulation. Neither photoperiod nor food availability had an effect on food storing behavior. Fat and body mass transiently increased in both groups exposed to short duration of food availability, regardless of photoperiod, but did not increase in birds exposed to long days with long duration food availability. These results indicate that duration of time to feed may affect seasonal changes in energy reserves in addition to any effects of photoperiod.
许多动物会季节性地改变能量储备，如食物贮藏和脂肪沉积。两个可能影响能量储备的因素是日照时长的变化和食物可获得性。我们研究了黑头山雀的食物贮藏和脂肪水平，以确定它们如何受到光照时长变化和食物可获得时长变化的影响。由于之前的研究混淆了光周期的影响和获取食物时长的影响，我们对这些变量进行了独立操控。鸟类被暴露于长日照（15小时光照，15小时食物可获得时间）、长日照光照暴露和短日照食物可获得时间（15小时光照，9小时食物）或短日照（9小时光照，9小时食物）环境中。在这种操控之前的2周和之后的3周内，我们在1小时的测试时段中测量了体重、体脂以及贮藏的葵花籽数量。光周期和食物可获得性对食物贮藏行为均无影响。无论光周期如何，暴露于短食物可获得时长环境中的两组鸟类的脂肪和体重均短暂增加，但在暴露于长日照且长食物可获得时长环境中的鸟类中并未增加。这些结果表明，除了光周期的任何影响外，进食时间长短可能会影响能量储备的季节性变化。
