文章基本信息

标题：Failure of Cyclomorphic Features to Deter Size-Dependent Predation by Leptodora kindti on Daphnia lumholtzi
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作者：Eden L. Effert ; Charles L. Pederson
期刊名称：Journal of Freshwater Ecology
印刷版ISSN：0270-5060
电子版ISSN：2156-6941
出版年度：2006
卷号：21
期号：3
页码：457-466
DOI：10.1080/02705060.2006.9665023
出版社：Taylor & Francis
摘要：Crustacean zooplankton exhibit a variety of defenses which deter predation by gape-limited (e.g., planktivorous fish) and size-dependent (e.g., invertebrate) predators. Cyclomorphic changes in morphology of a prey item, such as production of head and tail spines, presumably decrease the likelihood of capture and consumption by either class of predator. Daphnia lumholtzi exhibits extreme cyclomorphic features throughout its life history. We investigated the vulnerabilities of different size classes of D. lumholtzi and the non-spined Daphnia pulex to the invertebrate predator Leptodora kindti. In trials with single prey species, L. kindti consumed D. lumholtzi neonates at a higher rate than D. pulex neonates, medium D. pulex, and large D. pulex. When the daphnids were offered together in equal numbers, L. kindti selected D. lumholtzi at a faster rate than D. pulex in all size classes. Our results suggest that instead of providing protection, D. lumholzi's helmet and tail spine may increase likelihood of detection and capture by L. kindti, while decreasing the probability of escape.