Behavioral Ecology Advance Access originally published online on October 30, 2008
Behavioral Ecology 2009 20(1):160-164; doi:10.1093/beheco/arn128
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Mate choice, operational sex ratio, and social promiscuity in a wild population of the long-snouted seahorse Hippocampus guttulatus
a School of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK b Project Seahorse, Fisheries Centre, University of British Columbia, 2202 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada c Pacific Biological Station, Fisheries and Oceans Canada, 3190 Hammond Bay Road, Nanaimo, British Columbia VNT 6N7, Canada d Instituto Nacional de Recursos Biológicos (IP)/IPIMAR, Avenida 5 de outubro s/n, 8700-305 Olhão, Portugal
Address correspondence to M-J. Naud, who is now at Department of Biology, Queen's University, Kingston, Canada and the Marine Biological Association of the United Kingdom, Plymouth, PL1 2PB, UK. E-mail: naudmj{at}queensu.ca.
| Abstract |
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Mate competition and mate choice are not mutually exclusive behaviors. Both behaviors may drive sexual selection in one or both sexes of a population. One of several factors affecting which behavior is exhibited by which sex is the operational sex ratio (OSR) in the study population. The present study combines behavioral observations in the field with controlled experiments in aquaria to investigate social interactions and mate choice in both male and female long-snouted seahorses Hippocampus guttulatus in the context of the population OSR. Compared with the more readily studied pipefishes, data on OSR and mate choice in seahorses are scarce in the published literature. Our field data provide novel evidence of social promiscuity, size-assortative mating, and an OSR that varies from being unbiased early and midseason to male biased at the end of the breeding season. Our mate choice experiments revealed intersexual differences in mate preference with males significantly preferring larger females to familiar ones. Taken together, our field and experimental results suggest that mate choice rather than intrasexual competition could drive sexual selection in seahorses.
Key words: assortative mating, reproductive behavior, sexual selection, Syngnathidae.
Received 30 April 2008; revised 11 July 2008; accepted 16 July 2008.