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Sex‐dependent carry‐over effects on timing of reproduction and fecundity of a migratory bird
Author(s) -
Saino Nicola,
Ambrosini Roberto,
Caprioli Manuela,
Romano Andrea,
Romano Maria,
Rubolini Diego,
Scandolara Chiara,
Liechti Felix
Publication year - 2017
Publication title -
journal of animal ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.134
H-Index - 157
eISSN - 1365-2656
pISSN - 0021-8790
DOI - 10.1111/1365-2656.12625
Subject(s) - phenology , fecundity , biology , ecology , seasonal breeder , hirundo , reproduction , normalized difference vegetation index , annual cycle , geography , demography , population , climate change , sociology
Summary Life of many organisms flows as a sequence of annual cycles. Timing of cyclical events is shaped by natural selection also via the domino effects that any life history stage has on the stages that follow. Such ‘carry‐over effects’ have major consequences for evolutionary, ecological and demographic processes, but the causes that generate their individual‐level variation, including the effect of sex, are poorly understood. We used light‐level geolocators to study carry‐over effects on the year‐round life cycle of the long‐distance migratory barn swallow ( H irundo rustica ) and sex‐dependent variation in their strength. Correlation analyses showed that timing of breeding influenced departure time for autumn migration in females but not in males. In addition, strong, time‐mediated carry‐over effects of timing of departure from the wintering areas in sub‐Saharan Africa for spring migration on timing of arrival to the breeding grounds in Italy and Switzerland operated in both sexes. However, carry‐over effects of spring migration phenology on breeding date and seasonal fecundity were observed among females but not among males. We used partial least squares path modelling to unveil the complex carry‐over effects of phenology during the non‐breeding season in combination with the ecological conditions experienced by individual swallows in the wintering area, as gauged by Normalized Difference Vegetation Index values ( NDVI ), on breeding performance. Phenology during the non‐breeding season combined with NDVI during wintering accounted for as much as 65–70% of variation in subsequent seasonal fecundity in females, while such carry‐over effects on breeding success of males were weaker. Intense, sex‐specific carry‐over effects can have impacted on evolutionary processes, including sexual selection, and affected phenological response to climate change, causing the large population decline observed in this species.