Local adaptation and embryonic plasticity affect antipredator traits in hatchling pond snails
Local adaptation and embryonic plasticity affect antipredator traits in hatchling pond snails
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局部适应和胚胎可塑性影响孵化池塘蜗牛的抗捕食性特征
DOI：
10.1111/fwb.12512
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发表时间：
2015
影响因子：
2.7
通讯作者：
S. Rundle
中科院分区：
文献类型：
--
作者：
S. Dalesman;A. Thomas;S. Rundle
在淡水无脊椎动物中，早期生活史阶段诱导防御的生物学机制还知之甚少，但在影响种群动态和生存方面可能与后期阶段同等重要，甚至更重要。在这里，我们研究了池塘蜗牛的胚胎在捕食者凯洛蒙的作用下如何改变与幼螺保护相关的特征(爬行行为和壳的大小)。我们还通过比较不同捕食风险水平的地点的反应标准：三个高风险地点(存在捕食性鱼类)和三个低风险地点(不存在捕食性鱼类)，调查了可塑性水平是否受到原产地的影响。2.将来自每个种群的钉螺F2胚胎暴露于捕食性鱼类(Tinca Tinca)的凯洛酮或控制其整个发育直到孵化的条件。然后在孵化后1天和7天测量它们的回避行为和大小(尖顶高度)。3.孵化后一天，高风险种群对捕食者的回避水平，主要是在水线上停留的时间显著高于低风险种群；然而，与对照条件下发育的蜗牛相比，暴露在捕食者线索作为胚胎的孵化蜗牛的逃避水平也增加了。在发育过程中，暴露在捕食者线索下的蜗牛体型较小，大小与回避行为之间存在强烈的负相关关系，这表明生长和行为之间存在权衡或特征补偿。4.在孵化后7天，发现了类似的回避行为模式，来自高风险栖息地的蜗牛和在发育过程中暴露于捕食者凯洛蒙的蜗牛的回避增加。在孵化后7天，主要的回避反应转变为爬行到水线以上。不同处理之间的壳大小没有显著差异，这表明暴露于捕食者的蜗牛表现出了追赶生长。这种在孵化后1天至7天期间对生长的投资增加，与处理组中回避行为的增加呈正相关，表明蜗牛转向了防御特征的特征共同专门化。5.在孵化后的最初几天，蜗牛改变了回避行为的类型，也改变了形态和行为防御特征之间的关系。这些防御特征在幼螺中的表达程度既受其发育环境的影响，也受其对捕食栖息地的局部适应的影响，这可能对生存有很大影响。
SUMMARY 1. The biology of induced defences in very early life history stages is poorly understood in freshwater invertebrates, but may be equally, if not more, important than later stages in influencing population dynamics and survival. Here, we investigated how exposure of embryos of the pond snail Lymnaea stagnalis to predator kairomones altered traits associated with protection (crawl out behaviour and shell size) in hatchling snails. We also investigated whether levels of plasticity were influenced by habitat of origin by comparing reaction norms from sites with different levels of predation risk: three high risk (predatory fish present) and three low risk (predatory fish absent). 2. F2 embryos from snails from each population were exposed to kairomones from a predatory fish (Tinca tinca) or control conditions for their entire development up to the point of hatching. Their avoidance behaviour and size (spire height) were then measured 1 day and 7 days after hatching. 3. One day post-hatching, levels of predator avoidance, primarily time spent at the water line, were significantly greater in high-risk versus low-risk populations; however, avoidance was also increased in hatchling snails exposed to predator cues as embryos, compared with those developing in control conditions. Snails exposed to predator cues during development were smaller, and there was a strong negative relationship between size and avoidance behaviour, suggesting a trade-off or trait compensation between growth and behaviour. 4. At 7 days post-hatching, a similar pattern in avoidance behaviour was found, with increased avoidance in snails from high-risk habitats and in those exposed to predator kairomones during their development. The primary avoidance response switched to crawling above the waterline at 7 days post-hatching. There was no significant difference in shell size between treatments, suggesting that predator-exposed snails had exhibited ‘catch-up’ growth. This enhanced investment in growth between 1 day and 7 days post-hatching was positively correlated with elevated avoidance behaviour across treatment groups, demonstrating that snails switched to trait co-specialisation of defence traits. 5. During the first few days post-hatching, snails alter the type of avoidance behaviour and also the relationship between morphological and behavioural defence traits. The degree of expression of these defensive traits in hatchling snails is influenced by both their developmental environment and local adaptation to their predation habitat that may have large implications for survival.