Abstracts (first author)
Evolutionary potential of arrival date on breeding grounds: selection, heritability and microevolution
In migratory species, timing of arrival on the breeding grounds in spring is crucial for the reproductive success. Thus, in the face of a changing environment, it is important to be able to adjust the timing accordingly. However, little is known about the genetic background and hence evolutionary potential of arrival date. We have used a multi-level approach to investigate the evolutionary potential of arrival date combining data from a multigenerational pedigree and novel migration tracking techniques of a natural population of great reed warblers (Acrocephalus arundinaceus). We found that selection favours early arrival both in male and female great reed warblers, and that the trait is both repeatable and heritable. Further, arrival date in the population has advanced during the two decades of this study, a pattern that is in accordance with the response attributed to climate change reported in other migrant birds but also in accordance to the directional selection acting on the trait. Tracking the full migratory annual cycle of individual great reed warblers show that departure date from the wintering site determines arrival date and that spring migration is faster than autumn migration, corroborating the selection for earlier arrival. Our study is a first step towards dissecting the genetic and environmental factors that contribute to shape arrival date in long-distance migrant birds. Such analyses are essential if we want to understand how migratory species are able to cope with a rapidly changing environment.