Ferrari Maud C O, McCormick Mark I, Allan Bridie J M, Choi Rebecca, Ramasamy Ryan A, Johansen Jacob L, Mitchell Matthew D, Chivers Douglas P
Department of Biomedical Sciences, WCVM, University of Saskatchewan, SK, Canada.
ARC Centre of Excellence for Coral Reef Studies, and College of Marine &Environmental Sciences, James Cook University, Townsville, QLD, Australia.
Sci Rep. 2015 Oct 30;5:15537. doi: 10.1038/srep15537.
Prey individuals with complex life-histories often cannot predict the type of risk environment to which they will be exposed at each of their life stages. Because the level of investment in defences should match local risk conditions, we predict that these individuals should have the ability to modulate the expression of an integrated defensive phenotype, but this switch in expression should occur at key life-history transitions. We manipulated background level of risk in juvenile damselfish for four days following settlement (a key life-history transition) or 10 days post-settlement, and measured a suite of physiological and behavioural variables over 2 weeks. We found that settlement-stage fish exposed to high-risk conditions displayed behavioural and physiological alterations consistent with high-risk phenotypes, which gave them a survival advantage when exposed to predators. These changes were maintained for at least 2 weeks. The same exposure in post-settlement fish failed to elicit a change in some traits, while the expression of other traits disappeared within a week. Our results are consistent with those expected from phenotypic resonance. Expression of antipredator traits may be masked if individuals are not exposed to certain conditions at key ontogenetic stages.
具有复杂生活史的猎物个体往往无法预测它们在每个生命阶段将面临的风险环境类型。由于对防御的投资水平应与当地风险状况相匹配，我们预测这些个体应具备调节综合防御表型表达的能力，但这种表达的转变应发生在关键的生活史转变阶段。我们在幼体雀鲷定居（一个关键的生活史转变）后的四天或定居后十天，对其风险背景水平进行了为期四天的操控，并在两周内测量了一系列生理和行为变量。我们发现，处于定居阶段且暴露于高风险条件下的鱼类表现出与高风险表型一致的行为和生理变化，这使它们在面对捕食者时具有生存优势。这些变化至少维持了两周。对定居后鱼类进行相同的暴露处理，未能引起某些性状的变化，而其他性状的表达在一周内就消失了。我们的结果与表型共振的预期结果一致。如果个体在关键的个体发育阶段未暴露于特定条件下，反捕食性状的表达可能会被掩盖。
