Territoriality varies across elevation in a Hawaiian songbird

Reproductive territoriality can be influenced by external and internal variables. Trade-offs between reproductive behaviors and other costly biological processes, such as immunity, exist across taxa, but the effects of novel diseases on these trade-offs remain poorly understood. Since the introduction of avian malaria to Hawaii in the early 1900s, low elevation Hawaii Amakihi (Chlorodrepanis virens) populations, which have undergone strong selection by the disease, have evolved increased malaria resilience. However, the effects of malaria selection on trade-offs between immunity and reproduction in Amakihi remain largely unknown. To begin exploring this relationship, we conducted simulated territorial intrusions on Amakihi at low elevation (where malaria selection has been stronger) and high elevation (where selection has been weaker) on Hawaii Island during the breeding season. We hypothesized that selection by avian malaria has favored greater investment in avian malaria resilience at...繁殖领域性（reproductive territoriality）可受内外变量的调控。各生物类群普遍存在繁殖行为与免疫等耗能生物学过程之间的权衡关系，但新兴疾病对这类权衡的影响机制仍未被充分阐明。自20世纪初禽疟（avian malaria）传入夏威夷群岛以来，经历该疾病强烈选择压力的低海拔夏威夷吸蜜鸟（Chlorodrepanis virens）种群，已演化出更强的疟原虫抗性。然而，疟原虫选择压力对吸蜜鸟免疫与繁殖间权衡关系的影响，目前仍鲜为人知。为探究这一关联，本研究在繁殖季对夏威夷岛的低海拔（疟原虫选择压力更强）与高海拔（选择压力较弱）生境中的吸蜜鸟开展了模拟领域入侵实验。我们提出假说：禽疟带来的选择压力，更倾向于提升种群对禽疟的抗性投入……