Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada.
British Columbia Ministry of the Environment, Vancouver, British Columbia, Canada.
J Fish Biol. 2021 Sep;99(3):955-963. doi: 10.1111/jfb.14781. Epub 2021 May 30.
A proactive-reactive continuum integrating multiple (i.e., 3+) dimensions of animal behaviour has been reported as a major axis of behavioural differentiation, but its stability along a biological hierarchy from individuals to populations remains speculative. Piscivore and insectivore rainbow trout (Oncorhynchus mykiss) represent closely related ecotypes with strong ecological divergence driven by selection for a large-bodied piscivorous lifestyle with fast juvenile growth vs. selection for smaller adult body size and lower growth associated with an insectivorous diet. To evaluate whether differences in behaviour between ecotypes are consistent with a proactive-reactive axis and consistent along a biological hierarchy, the authors examined variation in emergence time from a shelter, exploration, activity and predator inspection among individuals, populations and ecotypes of juvenile piscivore and insectivore rainbow trout O. mykiss. As expected, the faster-growing piscivore ecotype was more proactive (i.e., shorter emergence time, exploration and predator inspection) than the more reactive insectivore ecotype. This behavioural contrast was partly maintained across populations, although activity differences were most pronounced among populations, rather than emergence time. Insectivore fry showed substantial variation in behavioural expression among individuals within populations; by contrast, piscivores showed highly similar proactive behaviours with significantly lower inter-individual variation in behavioural expression, suggesting intense selection on behaviour supporting their faster growth. This work suggests that piscivore and insectivore O. mykiss broadly differ in behaviour along a proactive vs. reactive continuum, and highlights the greater multidimensionality of behavioural expression within the insectivore ecotype. Contrasting behaviours between ecotypes may result from differential selection for slow vs. fast juvenile growth and associated metabolism, and may contribute to adult trophic specialization.
已报道称，一种整合了动物行为多个（即 3 个以上）维度的主动-反应连续体是行为分化的主要轴，但它在个体到种群的生物层次上的稳定性仍存在推测。肉食性和食虫性虹鳟（Oncorhynchus mykiss）代表了密切相关的生态型，由于选择大体型肉食性生活方式和快速幼体生长而与选择较小成年体型和与食虫性饮食相关的较低生长之间存在强烈的生态分歧，从而导致行为上存在强烈的生态分歧。为了评估生态型之间的行为差异是否与主动-反应轴一致，并且是否沿着生物层次一致，作者研究了幼鱼肉食性和食虫性虹鳟 O. mykiss 的个体、种群和生态型之间从庇护所中出现的时间、探索、活动和捕食者检查等行为差异。正如预期的那样，生长速度较快的肉食性生态型比反应性更强的食虫性生态型更主动（即出现时间更短、探索和捕食者检查）。这种行为对比在一定程度上保持在种群之间，尽管活动差异在种群之间最为明显，而不是出现时间。食虫性鱼苗在种群内个体之间表现出相当大的行为表达变化；相比之下，肉食性鱼苗表现出高度相似的主动行为，行为表达的个体间差异显著降低，这表明行为选择强烈，支持其更快的生长。这项工作表明，肉食性和食虫性 O. mykiss 沿着主动与反应连续体在行为上广泛不同，并突出了食虫性生态型中行为表达的更大多维性。生态型之间的对比行为可能是由于对慢或快幼体生长和相关代谢的选择不同，并且可能有助于成年营养特化。
