Denoël M, Drapeau L, Oromi N, Winandy L
Behavioural Biology Group, Laboratory of Fish and Amphibian Ethology, Freshwater and OCeanic science Unit of reSearch (FOCUS), University of Liège (ULiège), Liège, Belgium.
Laboratoire Evolution et Diversité Biologique, CNRS, UMR 5174, Université Paul Sabatier, Toulouse, France.
Oecologia. 2019 Mar;189(3):637-645. doi: 10.1007/s00442-019-04362-8. Epub 2019 Feb 26.
Evolutionary theory predicts the evolution of metamorphosis over paedomorphosis (the retention of larval traits at the adult stage) in response to life in unfavourable habitats and to the benefits of dispersal. Although many organisms are canalised into obligatory complex or simple life cycles, some species of newts and salamanders can express both processes (facultative paedomorphosis). Previous research highlighted the detrimental effect of fish on both metamorphic and paedomorphic phenotypes, but it remains unknown whether predation risk could induce shifts from paedomorphosis to metamorphosis, whether behavioural avoidance could be an alternative strategy to metamorphosis and whether these responses could be sex-biased. Testing these hypotheses is important because metamorphosed paedomorphs are dispersal individuals which could favour the long-term persistence of the process by breeding subsequently in more favourable waters. Therefore, we quantified the spatial behaviour and timing of the metamorphosis of facultative paedomorphic palmate newts Lissotriton helveticus in response to predation risk. We found that fish induced both male and female paedomorphs to hide more often, but behavioural avoidance was not predictive of metamorphosis. Paedomorphs did not metamorphose more in the presence of fish, yet there was an interaction between sex and predation risk in metamorphosis timing. These results improve our understanding of the lower prevalence of paedomorphs in fish environments and of the female-biased sex ratios in natural populations of paedomorphic newts. Integrating sex-dependent payoffs of polyphenisms and dispersal across habitats is therefore essential to understand the evolution of these processes in response to environmental change.
进化理论预测，在不利栖息地的生活以及扩散的益处会促使变态相对于幼态持续（即在成年阶段保留幼虫特征）而进化。尽管许多生物被限定为具有 obligatory 复杂或简单的生命周期，但一些蝾螈和火蜥蜴物种可以表现出这两种过程（兼性幼态持续）。先前的研究强调了鱼类对变态和幼态持续表型的有害影响，但捕食风险是否会导致从幼态持续转变为变态、行为回避是否可能是变态的替代策略以及这些反应是否存在性别差异仍不清楚。检验这些假设很重要，因为变态后的幼态持续个体是扩散个体，它们随后在更适宜的水域繁殖可能有利于该过程的长期持续。因此，我们量化了兼性幼态持续的掌状蝾螈（Lissotriton helveticus）在面对捕食风险时的空间行为和变态时间。我们发现，鱼类会促使雄性和雌性幼态持续个体更频繁地躲藏，但行为回避并不能预测变态。在有鱼的情况下，幼态持续个体并不会更多地变态，然而在变态时间上存在性别与捕食风险之间的相互作用。这些结果增进了我们对鱼类环境中幼态持续个体较低发生率以及幼态持续蝾螈自然种群中雌性偏向性别比例的理解。因此，整合多态性和跨栖息地扩散的性别依赖性收益对于理解这些过程在应对环境变化时的进化至关重要。 （注：“obligatory”这里翻译为“限定的”，结合语境可能不太准确，但因未明确其在生物学中更准确的专业释义，暂这样翻译。）
