キオビスズメダイのmobbing行動

Mobbing of potential predators, a behavior long known for birds, has only recently been reported for fishes.Mobbing by fishes has been simply defined as the assemblage of individuals around a potentially dangerous predator (Dominey, 1983).Possible functions of this behavior include advertisement of the presence of a predator (Dominey, 1983), driving the predator from a given area, or cultural transmission of predator identity (Curio, 1978).Mobbing behavior has been reported chiefly from colonially nesting fishes, and serves to protect nesting adults rather than eggs present in a nest (Fricke, 1973;Dominey, 1983).It has also been reported for non-territorial and occasionally territorial coral-reef species (Motta, 1983).Here I report mobbing behavior by the damselfish Stegastes albifasciatus (Schlegel et Miiller), a non-nesting inhabitant of coral reef flat territorial mosaics.<BR>A territorial mosaic consists of contiguous territories occupied for long periods of time by single animals (Keenleyside, 1979).Pomacentrid territorial mosaics are characterized by having single adults of both sexes occupying and defending small areas of the substrate, usually in patches of coral rubble (Sale, 1974).Territories are relatively stable and non-overlapping (Keenleyside, 1979), except in heterospecific mosaics where territory boundary overlap can occur (Donaldson, 1981).Mosaic territories support feeding, breeding (courtship and nesting), sheltering and resting activities (Keenleyside, 1979) but function primarily as a means for protecting a limited food source, usually benthic algae (Low, 1971;Vine, 1974;Ebersole, 1977; Hixon, 1980).