DeRango Eugene J, Schwarz Jonas F L, Piedrahita Paolo, Páez-Rosas Diego, Crocker Daniel E, Krüger Oliver
Department of Animal Behaviour Bielefeld University Bielefeld Germany.
Facultad de Ciencias de la Vida Escuela Superior Politécnica del Litoral Guayaquil Ecuador.
Ecol Evol. 2021 May 3;11(12):7579-7590. doi: 10.1002/ece3.7590. eCollection 2021 Jun.
Hormones are extensively known to be physiological mediators of energy mobilization and allow animals to adjust behavioral performance in response to their environment, especially within a foraging context.Few studies, however, have narrowed focus toward the consistency of hormonal patterns and their impact on individual foraging behavior. Describing these relationships can further our understanding of how individuals cope with heterogeneous environments and exploit different ecological niches.To address this, we measured between- and within-individual variation of basal cortisol (CORT), thyroid hormone T3, and testosterone (TEST) levels in wild adult female Galápagos sea lions () and analyzed how these hormones may be associated with foraging strategies. In this marine predator, females exhibit one of three spatially and temporally distinct foraging patterns (i.e., "benthic," "pelagic," and "night" divers) within diverse habitat types.Night divers differentiated from other strategies by having lower T3 levels. Considering metabolic costs, night divers may represent an energetically conservative strategy with shorter dive durations, depths, and descent rates to exploit prey which migrate up the water column based on vertical diel patterns.Intriguingly, CORT and TEST levels were highest in benthic divers, a strategy characterized by congregating around limited, shallow seafloors to specialize on confined yet reliable prey. This pattern may reflect hormone-mediated behavioral responses to specific risks in these habitats, such as high competition with conspecifics, prey predictability, or greater risks of predation.Overall, our study highlights the collective effects of hormonal and ecological variation on marine foraging. In doing so, we provide insights into how mechanistic constraints and environmental pressures may facilitate individual specialization in adaptive behavior in wild populations.
激素作为能量动员的生理介质已广为人知，它能使动物根据环境调整行为表现，尤其是在觅食环境中。然而，很少有研究聚焦于激素模式的一致性及其对个体觅食行为的影响。描述这些关系有助于我们进一步理解个体如何应对异质环境并利用不同的生态位。为解决这一问题，我们测量了野生成年雌性加拉帕戈斯海狮体内基础皮质醇（CORT）、甲状腺激素T3和睾酮（TEST）水平的个体间和个体内差异，并分析了这些激素与觅食策略之间的关联。在这种海洋捕食者中，雌性在不同的栖息地类型中呈现出三种空间和时间上不同的觅食模式之一（即“底栖”、“远洋”和“夜间”潜水者）。夜间潜水者与其他策略的区别在于T3水平较低。考虑到代谢成本，夜间潜水者可能代表一种能量保守的策略，其潜水持续时间、深度和下降速度较短，以捕食根据垂直昼夜模式在水柱中向上迁移的猎物。有趣的是，底栖潜水者的CORT和TEST水平最高，这种策略的特点是聚集在有限的浅海海底周围，专门捕食有限但可靠的猎物。这种模式可能反映了激素介导的对这些栖息地特定风险的行为反应，例如与同种个体的激烈竞争、猎物的可预测性或更大的捕食风险。总体而言，我们的研究强调了激素和生态变化对海洋觅食的综合影响。通过这样做，我们深入了解了机制限制和环境压力如何促进野生种群适应性行为的个体专业化。
