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Uncertainty in territory quality affects the benefits of usurpation in

Summary: Uncertainty in territory quality affects
the benefits of usurpation in
a Mediterranean wrasse
Suzanne H. Alonzo
Institute of Marine Sciences, University of California, Santa Cruz, 1156 High Street, Santa Cruz,
CA 95064, USA
Individuals should defend sites when the expected benefits of the territory exceed the cost of defense. However, if territory
qulaity is unpredictable or difficult to assess, the expected pattern of territorial behavior is less clear. In a Mediterranean wrasse,
Symphodus ocellatus, mating success is skewed with 2% of nesting males getting more than 20% of the spawning success. Yet,
variation in mating success is not explained by any known physical characteristic of males or their territories. Instead, females
prefer nests with a recent history of mating success because males are less likely to desert the offspring she leaves behind. Thus,
territory quality is transient and determined by interactions between the sexes. I measured the frequency of territorial takeovers
and the uncertainty in mating success among days at a nest. Observations indicated that S. ocellatus males usurped their
neighbor's successful nests when males were unsuccessful and larger than their successful neighbor. Sites that achieved mating
success had a significantly higher probability (0.84) of remaining sucessful between consecutive days than unsuccessful territories
had of becoming successful (0.30). Unsuccessful males obtained higher and more certain fitness returns if they usurped
a successful neighbor's territory. Interactions within and between the sexes drive uncertainty in success, which influences ter-
ritorial behavior in this species. Key words: territoriality, stochasticity, labridae, sexual conflict, assessment. [Behav Ecol 15:278285
Individuals should defend sites or take over territories when


Source: Alonzo, Suzanne H. - Department of Ecology and Evolutionary Biology, Yale University


Collections: Environmental Sciences and Ecology; Biology and Medicine