Uncertainty in territory quality affects the benefits of usurpation in a Mediterranean wrasse

摘要: Individuals should defend sites when the expected benefits of territory exceed cost defense. However, if qulaity is unpredictable or difficult to assess, pattern territorial behavior less clear. In a Mediterranean wrasse, Symphodus ocellatus, mating success skewed with 2% nesting males getting more than 20% spawning success. Yet, variation in not explained by any known physical characteristic their territories. Instead, females prefer nests recent history because are likely desert offspring she leaves behind. Thus, quality transient and determined interactions between sexes. I measured frequency takeovers uncertainty among days at nest. Observations indicated that S. ocellatus usurped neighbor’s successful were unsuccessful larger neighbor. Sites achieved had significantly higher probability (0.84) remaining sucessful consecutive territories becoming (0.30). Unsuccessful obtained certain fitness returns they territory. Interactions within sexes drive success, which influences this species. Key words: territoriality, stochasticity, labridae, sexual conflict, assessment. [Behav Ecol 15:278–285 (2004)]