Gordon Timothy A C, Neto-Cerejeira Joana, Furey Paula C, O'Gorman Eoin J
Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, Berkshire, SL5 7PY, UK.
Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
Curr Zool. 2018 Apr;64(2):231-242. doi: 10.1093/cz/zoy011. Epub 2018 Jan 27.
Environmental warming places physiological constraints on organisms, which may be mitigated by their feeding behavior. Theory predicts that consumers should increase their feeding selectivity for more energetically valuable resources in warmer environments to offset the disproportionate increase in metabolic demand relative to ingestion rate. This may also result in a change in feeding strategy or a shift towards a more specialist diet. This study used a natural warming experiment to investigate temperature effects on the feeding selectivity of three freshwater invertebrate grazers: the snail , the blackfly larva , and the midgefly larva . Chesson's Selectivity Index was used to compare the proportional abundance of diatom species in the guts of each invertebrate species with corresponding rock biofilms sampled from streams of different temperature. The snails became more selective in warmer streams, choosing high profile epilithic diatoms over other guilds and feeding on a lower diversity of diatom species. The blackfly larvae appeared to switch from active collector gathering of sessile high profile diatoms to more passive filter feeding of motile diatoms in warmer streams. No changes in selectivity were observed for the midgefly larvae, whose diet was representative of resource availability in the environment. These results suggest that key primary consumers in freshwater streams, which constitute a major portion of invertebrate biomass, can change their feeding behavior in warmer waters in a range of different ways. These patterns could potentially lead to fundamental changes in the flow of energy through freshwater food webs.
环境变暖对生物体施加了生理限制，而这种限制可能会通过它们的摄食行为得到缓解。理论预测，在温暖的环境中，消费者应该提高对能量价值更高的资源的摄食选择性，以抵消代谢需求相对于摄食率不成比例的增加。这也可能导致摄食策略的改变或转向更具专业性的饮食。本研究采用自然变暖实验来研究温度对三种淡水无脊椎动物食草动物摄食选择性的影响：蜗牛、蚋幼虫和摇蚊幼虫。使用切森选择性指数将每种无脊椎动物肠道中硅藻物种的相对丰度与从不同温度溪流中采集的相应岩石生物膜进行比较。在较温暖的溪流中，蜗牛变得更具选择性，选择高姿态的附生硅藻而非其他类群，并以种类较少的硅藻为食。在较温暖的溪流中，蚋幼虫似乎从积极收集固着的高姿态硅藻转变为更被动地滤食活动的硅藻。摇蚊幼虫的选择性没有变化，其食物组成代表了环境中的资源可利用情况。这些结果表明，构成无脊椎动物生物量主要部分的淡水溪流中的关键初级消费者，可以在温暖水域以一系列不同方式改变它们的摄食行为。这些模式可能会导致淡水食物网能量流动的根本变化。
