Although seasonality is widespread and can cause fluctuations in the intensity and direction of natural selection, we have little information about the consequences of seasonal fitness trade-offs for population dynamics. Here we exposed populations of Drosophila melanogaster to repeated seasonal changes in resources across 58 generations and used experimental and mathematical approaches to investigate how viability selection on body size in the non-breeding season could affect demography. We show that opposing seasonal episodes of natural selection on body size interacted with both direct and delayed density dependence to cause populations to undergo predictable multigenerational density cycles. Our results provide evidence that seasonality can set the conditions for life-history trade-offs and density dependence, which can, in turn, interact to cause multigenerational population cycles.
- Gustavo Sigrist Betini
- Andrew G McAdam
- Cortland K Griswold
- D Ryan Norris
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Lutz Becks, Max Planck Institute for Evolutionary Biology, Germany
© 2017, Betini et al.
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