Behavioral Ecology Advance Access published online on December 7, 2007
Behavioral Ecology, doi:10.1093/beheco/arm129
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Sexual conflict over breeding substrate causes female expulsion and offspring loss in a cichlid fish
a Section of Integrative Biology, University of Texas at Austin, 1 University Station C0930, Austin, TX 78712, USA b Department of Behavioural Ecology, Zoological Institute, University of Bern, Wohlenstrasse 50a, CH-3032 Hinterkappelen, Switzerland
Address correspondence to M.E. Maan. E-mail: m.maan{at}mail.utexas.edu.
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Abstract |
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Females of the Lake Tanganyika cichlid Lamprologus callipterus exclusively breed in empty snail shells that males collect in their territories. Male–male competition for shells is severe, leading to frequent shell stealing and territory takeover. As a consequence, males have breeding females in their shells that spawned with competitors. In this field study, we investigated both naturally occurring and experimentally induced encounters of territorial males with females that had spawned with other males. We found that the breeding success of females that were taken over by a different male was significantly reduced. Behavioral observations after experimental shell relocation further showed that males recognized females that they had not spawned with: males directed more exploration and manipulation behavior toward such shells compared with controls. Reoccupation rate of emptied experimental shells was significantly higher than that of unmanipulated empty shells. This indicates that shell stealing and nest takeover, followed by female expulsion, contribute to the reproductive success of L. callipterus males. We also found that female mate choice reduces expulsion risk: females preferred to mate with large males, and male size correlated with dominance. We conclude that the limited availability of breeding substrate is a key determinant of both intrasexual competition and intersexual conflict in this species.
Key words: cichlid fish, infanticide, Lake Tanganyika, Lamprologus callipterus, resource defense polygyny, shell brooding.
Received 21 August 2006; revised 18 May 2007; accepted 6 November 2007.