文章基本信息

标题：In deep trouble: Habitat selection constrained by multiple enemies in zooplankton
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作者：Ellen Decaestecker ; Luc De Meester ; Dieter Ebert 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2002
卷号：99
期号：8
页码：5481-5485
DOI：10.1073/pnas.082543099
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Habitat selection behavior is an important predator-avoidance strategy for many organisms. Its particular expression is often explained as the result of a tradeoff between avoiding antagonists and acquiring resources. However, there is need for a broader perspective on this behavior, as organisms are often simultaneously involved in complex antagonistic relationships with multiple types of enemies. We show experimentally that a tradeoff between predator and parasite avoidance may be important in the evolution of habitat selection behavior in the waterflea, Daphnia magna. In this species, negatively phototactic clones suffer less from visually hunting predators by residing in deeper and darker portions of the water column during the day. However, this behavior increases the risk of parasitic infections when the Daphnia are exposed to pond sediments containing parasite spores. Positively phototactic clones, which are at a higher risk of predation, are less exposed to parasite spores in the sediment and consequently suffer less from parasitic infection. We show that the increased risk of infection remains even if the animals change their phototactic behavior on exposure to chemical cues from fish. This tradeoff highlights a substantial cost of predator-induced changes in habitat selection behavior. Tradeoffs caused by multiple enemies may explain genetic polymorphism for habitat selection behavior in many natural populations.