Aggression and courtship behavior were examined of wild Drosophila melanogaster flies isolated from two contrasting microclimates found at Evolution Canyon in Mt. Carmel, Israel: an African-like dry tropical Slope (AS) and a European-like humid temperate Slope (ES), separated by 250 meters. Studies were carried out to ask whether behavioral differences existed between the two populations obtained from opposite slopes with divergent microclimates in Israel. First, we measured and compared intraslope aggression between same sex fly pairings collected from the same slope. Both male and female flies displayed similar fighting abilities from both slopes. ES males, however, from the humid biome, showed a tendency to lunge more per aggressive encounter, compared with AS males from the dry biome. Next, we tested interslope aggression by pairing flies from opposite slopes. ES males displayed higher numbers of lunges, and won more fights against their AS opponents. We also observed enhanced courtship performances in ES compared to AS males. The fighting and courtship superiority seen in ES males could reinforce fitness and pre-mating reproductive isolation mechanisms that underlie incipient sympatric speciation. This may support an evolutionary advantage of adaptively divergent fruit fly aggression phenotypes from different environments.
Bibliographical noteFunding Information:
We thank all the members of the Kravitz Lab for many helpful discussions and support on this project, Edward A. Kravitz for his critical evaluation and editing of the manuscript and Jacqueline Palavicino for figure design. These studies were supported by NIH R35-MIRA grant 1-R35-GM118137-01. Eviatar Nevo thanks the Ancell Teicher Research Foundation of Genetics and Molecular Evolution for financial support. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
© 2019, The Author(s).
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