Abstract
In a sex role reversed pipefish, Syngnathus typhle, we found that basic life history allocations were directly influenced by sexual selection. We investigated time allocation to foraging and mating, respectively, in a choice experiment, giving males and females, of small or large body size, a choice between food and a potential partner. We found that males were more interested in foraging than mating, i.e., were more frequently observed in front of the food than in front of the partner, whereas females were more interested in the potential partner. This reflects sexual selection operating differently on the two sexes, as males and females are relatively similar in other life history traits, such as growth, mortality, age of maturity, dispersal, and parental expenditure. Moreover, large individuals allocated more time to mating activities, small to feeding. Individuals more interested in mating compared to food were subsequently more critical when given a choice between a large (high-quality) and a small (low-quality) partner, whereas individuals more interested in food were not selective. These findings are consistent with our predictions: sex-role reversed males can be relatively sure of achieving one or more matings, and should allocate more time to feeding and, hence, to parental investment, growth and/or future reproduction. Females, on the other hand, have more uncertain mating prospects and should allocate time to imminent reproductive activities, thereby foregoing other life history traits such as growth and future egg production. By this, they also sacrifice future fecundity and attractiveness.
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Acknowledgements
We thank Elias Berglund, Emma Berglund, and Ronny Höglund for their valuable assistance in the field and lab. Thanks to Ingrid Ahnesjö, Anna Qvarnström, and two anonymous referees for their valuable comments on the manuscript. The work was funded by grants to A. B. from the Swedish Research Council, to G. R. from the Norwegian Research Council and to S. R. W. from Uppsala University and the Swedish Royal Academy of Science. Thanks to Kristineberg Marine Research Station for the research facilities. The experiments reported in this study comply with the Swedish laws.
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Communicated by C. St. Mary
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Berglund, A., Rosenqvist, G. & Robinson-Wolrath, S. Food or sex—males and females in a sex role reversed pipefish have different interests. Behav Ecol Sociobiol 60, 281–287 (2006). https://doi.org/10.1007/s00265-006-0166-4
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DOI: https://doi.org/10.1007/s00265-006-0166-4