Life-history responses to Chuoborus of spined and unspined Daphniu pulex
Life-history responses to Chuoborus of spined and unspined Daphniu pulex
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有刺和无刺水蚤对 Chuoborus 的生活史反应
DOI：
10.1093/plankt/17.1.71
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
J. Lüning
中科院分区：
文献类型：
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作者：
J. Lüning
众所周知，捕食性幻影侏儒Chaoborus的幼虫释放的水媒化学物质可以诱导其捕食性水蚤的形态改变：这些枝角类动物发育出可能带有几颗牙齿的颈刺。一些研究表明，这些形态变化增加了猎物逃脱的机会。但由于这些颈部牙齿不是固定的防御反应，它们被认为会带来某种形式的成本，如延迟成熟和降低生殖力。在这项研究中。本文研究了在有无黄毛藻的情况下饲养的4个水蚤无性系的形态变化与生活史变化的关系。特别强调了修改的基因类型比较。虽然所有四个克隆在存在Chaoborus的情况下都表现出成熟时间的延迟，但不同基因型的颈椎反应明显不同：一个克隆从来没有任何颈部牙齿，另一个总是产生一颗牙齿，两个克隆产生不同数量的每个脊椎的牙齿(分别为2.9和4)。这些结果表明，不存在与发育迟缓相对应的颈齿发育的一般规律。这似乎是两个独立的、可能是适应性反应的遗传变异。然而，没有颈齿的克隆是唯一没有表现出捕食者导致繁殖力下降的克隆。另一种常见的形态反应是所有无性系的幼虫都长出了细长的尾刺。
Water-borne chemicals released by the larvae of the predatory phantom midgeChaoborusare known to induce morphological modifications in its preyDaphnia pulex: these cladocerans develop neck spines which may carry several teeth. Some work has shown that these morphological variations enhance the prey's chances of escape. but since these neck teeth are not fixed defence reactions, they are thought to entail some form of cost, such as delayed maturation and reduced fecundity. In this study. the relationship between morphological and life-history changes in four clones ofDaphnia pulexreared in the presence and absence ofChaoborus flavicanswas examined. Special emphasis was placed on the genotypic comparison of the modifications. While all four clones showed a delay in maturation time in the presence ofChaoborus, the neck spine responses differed markedly among the genotypes: one clone never had any neck teeth, another always produced one single tooth, and two clones produced varying numbers of teeth per spine (means 2.9 and 4. respectively). These results indicate that there is no general pattern of neck teeth production corresponding to delayed maturation. What there appears to be is genetic variability in two independent and possibly adaptive responses. However, the clone without neck teeth was the only one which showed no predator-induced reduction in fecundity. Another common morphological response toChaoboruswas that juveniles of all clones developed elongated tail spines.