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Sexually antagonistic coevolution in a mating system: combining experimental and comparative approaches to address
1Department of Zoology, University of Toronto, Ontario, Canada. lrowe@zoo.toronto.edu
Summary
Water strider mating behaviors evolve through sexually antagonistic coevolution, where male persistence and female resistance traits shape mating activity. Evolution is not historically constrained, showing flexibility in male or female advantage.
Area of Science:
- Evolutionary biology
- Behavioral ecology
- Animal behavior
Background:
- Water striders (Gerris spp.) exhibit costly multiple mating for females, leading to sexual conflict over mating.
- Variation in mating behaviors may arise from differing optimal female mating rates or sexually antagonistic coevolution.
Purpose of the Study:
- To investigate the evolution of mating behaviors in 15 Gerrid species.
- To test hypotheses of interspecific variation in optimal female mating rate versus sexually antagonistic coevolution.
- To examine the role of male grasping and female antigrasping structures in premating struggles.
Main Methods:
- Combined experimental and comparative techniques.
- Quantified 20 behavioral variables across 15 Gerris species.
- Assessed behavioral responses to environmentally induced sex-ratio changes.
Main Results:
- Significant interspecific variation in mating behaviors was observed, yet species shared common behavioral repertoires.
- A single multivariate axis explained over 50% of the variation in behaviors and their response to sex ratio.
- Antagonistic coevolution of traits controlling premating struggles best explained correlated evolution patterns.
Conclusions:
- Mating behaviors in Gerris spp. show tight coevolution within a shared mating system.
- The relative advantage of males or females in controlling mating outcomes correlates with mating activity levels.
- Evolutionary trajectories appear unconstrained by history, with no consistent bias toward male or female advantage.