U.S. Geological Survey, Montana Cooperative Wildlife Research Unit, University of Montana, Missoula, MT 59812, USA.
Science. 2015 Aug 28;349(6251):966-70. doi: 10.1126/science.aad1173.
Life history theory attempts to explain why species differ in offspring number and quality, growth rate, and parental effort. I show that unappreciated interactions of these traits in response to age-related mortality risk challenge traditional perspectives and explain life history evolution in songbirds. Counter to a long-standing paradigm, tropical songbirds grow at similar overall rates to temperate species but grow wings relatively faster. These growth tactics are favored by predation risk, both in and after leaving the nest, and are facilitated by greater provisioning of individual offspring by parents. Increased provisioning of individual offspring depends on partitioning effort among fewer young because of constraints on effort from adult and nest mortality. These growth and provisioning responses to mortality risk finally explain the conundrum of small clutch sizes of tropical birds.
生命史理论试图解释为什么物种在后代数量和质量、生长率以及亲代投入方面存在差异。我表明，这些特征在应对与年龄相关的死亡率风险时的相互作用，如果得不到重视，将挑战传统观点，并解释鸣禽的生命史进化。与长期以来的范式相反，热带鸣禽的整体生长速度与温带物种相似，但翅膀的生长速度相对较快。这些生长策略受到捕食风险的青睐，无论是在巢内还是离开巢后，并且由于成年和巢死亡率对努力的限制，父母为每个后代提供更多的养育。个体后代的养育投入的增加取决于将努力分配给较少的幼鸟，因为这受到成鸟和巢死亡率的限制。这些对死亡率风险的生长和养育反应最终解释了热带鸟类小窝卵数的难题。
