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Agricultural management affects evolutionary processes in a migratory songbird
Noah G Perlut1, Corey R Freeman-Gallant, Allan M Strong
1United States Geological Survey, Burlington, VT, USA. nperlut@uvm.edu
Molecular Ecology
|February 28, 2008
Summary
Hay harvests disrupt Savannah sparrow mating systems, increasing social monogamy and the opportunity for sexual selection. This agricultural practice significantly impacts bird mating patterns and evolutionary processes.
Area of Science:
- Ecology
- Evolutionary Biology
- Ornithology
Background:
- Hay harvesting causes nest failure in breeding songbirds.
- The impact of hay harvesting on evolutionary processes, particularly mating patterns, is not well understood.
Purpose of the Study:
- To investigate how hay harvesting affects social and genetic mating patterns in Savannah sparrows (Passerculus sandwichensis).
- To determine the consequences for sexual selection and evolutionary processes.
Main Methods:
- Comparison of mating patterns and extra-pair paternity (EPP) on harvested versus unharvested fields.
- Analysis of social monogamy, polygyny, and fertilization success in relation to haying activities.
Main Results:
- On unharvested fields, 55% of females were polygynous, with higher EPP rates.
- Hay harvesting led to simultaneous nest failure, increasing social monogamy and decreasing EPP.
- Despite increased monogamy, haying doubled the opportunity for sexual selection due to increased variance in mate quality and fertilization success.
Conclusions:
- Hay harvesting significantly alters mating systems and increases the opportunity for sexual selection in Savannah sparrows.
- These changes in mating patterns can have substantial population-level effects on evolutionary trajectories.
- Given extensive regional haying, these findings highlight a critical factor influencing avian evolution.
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