Bulgy tadpoles: inducible defense morph
Bulgy tadpoles: inducible defense morph
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DOI：
10.1007/s00442-004-1609-0
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发表时间：
2004-08-01
期刊：
影响因子：
2.7
通讯作者：
Nishimura, K
中科院分区：
文献类型：
--
作者：
Kishida, O;Nishimura, K
捕食者诱导的形态防御是由与捕食者相关的线索直接诱导的明显的形态变化。一般来说，远距离线索，即捕食者发出的化学物质或受损的同种生物，被认为是诱导水生环境形态变化的理想信号，而不是近距离线索，即近距离的化学或触觉线索，因为可以相对较长距离传播并持续很长时间的化学物质可能允许生物体保持安全并故意改变其形态。事实上，大多数采用诱导形态防御的生物利用远程化学线索来检测捕食风险并产生形态防御。在这篇文章中，我们报告了一个独特的和功能良好的诱导形态防御策略，其中诱导过程需要来自捕食者的近距离线索。小林蛙的蝌蚪在受到近距离捕食幼体小蜥蜴的威胁时，表现出隆起的身体形态。捕食实验和功能实验表明，诱导的突起形态是对张口受限捕食者幼虫的适应性防御表型。此外，在节约成本方面，海龟蝌蚪使用了两种适应性策略，即根据捕食风险调整膨大程度，以及在消除捕食威胁后通过实际收缩膨大的身体来逆转。一般情况下，水华轮虫的孵化时间早于迟滞轮虫。在天然池塘中，在早期发育阶段，孔雀蝌蚪生活在靠近幼虫的地方。随着它们的成长，火蜥蜴逐渐成为严重的捕食者，捕食者和猎物的相互作用变得亲密。经过一段时间后，捕食、自相残杀和变态减少了池塘中火蜥蜴的数量，捕食者和猎物之间的相互作用减弱。捕食者-猎物相互作用中的这种物候允许进化出一种接近线索的检测系统和自适应的成本节约策略。我们的结果强调了诱导防御的特征取决于捕食者-食饵系统的强度和专一性。
Predator induced morphological defenses are marked morphological shifts induced directly by cues associated with a predator. Generally, remote cues, i.e., chemical substances emitted from predators or injured conspecifics, are considered to be ideal signals to induce morphological change in aquatic environments rather than close cues, i.e., close chemical or tactile cues, since chemical substances that can propagate over relatively long distances and persist for a long period may allow organisms to keep safe and to deliberately change their morph. In fact, most organisms adopting an inducible morphological defense utilize remote chemical cues to detect predation risk and to produce morphological defenses. In this paper, we report a unique and functionally well designed inducible morphological defense strategy where the induction process requires close cues from a predator. The tadpoles of Rana pirica exhibited a bulgy bodied morphology when threatened with predation by larval salamanders, Hynobius retardatus, in close proximity. Predation trials and a function experiment showed that the induced bulgy morph is an adaptive defense phenotype against the gape-limited predator larval H. retardatus. Furthermore, R. pirica tadpoles use two adaptive strategies in terms of cost saving, i.e., adjustment of the extent of bulginess according to predation risk and reversibility by actual shrink of bulgy body after removing the predation threat. In general, R. pirica hatch earlier than H. retardatus. In natural ponds, during the early developmental stage R. pirica tadpoles live in close proximity to young H. retardatus larvae. As they grow, the salamanders gradually become serious predators and the predator-prey interaction becomes intimate. After a while, predation, cannibalism and metamorphosis decrease the number of salamanders in the ponds, and the predator-prey interaction weakens. Such a phenology in the predator-prey interaction allows the evolution of a close-cue detection system and adaptive cost-saving strategies. Our results highlight that the characteristics of the inducible defense depend on the intensity and specificity of the predator-prey system.