Short-term behavioral consequences of territory relocation in a Caribbean damselfish, Stegastes diencaeus

Home-range relocation occurs during natal and breeding dispersal, ontogenetic habitat shifts, and the maintenance of resourceor density-dependent patterns of distribution. Relocating animals are expected to change their behavior to compensate for limited familiarity with the new home range and with neighboring conspecifics; such changes may indicate some of the costs of relocation. Little is known, however, about the magnitude and duration of the changes or about the types of behavior affected. We investigated the short-term (2 day) behavioral changes associated with relocation in the highly territorial longfin damselfish, Stegastes diencaeus. We compared the behavior of newcomers settling into experimentally created vacancies in an established neighborhood with that of the original residents of the same territories. The greatest difference was an increase in the rate of agonistic interactions. Newcomers also used smaller territories, moved more, and fed less. Neighboring damselfishes were less aggressive toward neighbors that expanded into vacant territories than toward ‘‘strangers’’ that relocated from elsewhere. The behavior of newcomers approached that of original residents within 2 days but territory size did not. These observations suggest that relocating a territory increases energy expenditure and decreases energy intake. Such costs could explain the philopatry of reef fish when alternative locations are of uncertain quality or are only slightly better. Nevertheless, they are unlikely to outweigh the long-term benefits of obtaining a superior territory—especially for individuals from adjacent territories.