Territory Choice Guided By Familiar Object Cues From Earlier Territories in the Jewel Fish, Hemichromis Bimaculatus Gill 1862 (Pisces, Cichlidae)

Abstract

Abstract When two jewel fishes (Hemichromus binwculatus) in groups of 4 or 5 fishes are territorial, they retain identical territory positions with respect to the only transparent aquarium side permitting an outward look, after several transfers to new similar aquarium tanks (Exp. 1). If the cues on which such relative territory positions in equivalent tanks depend, are merely given by familiar objects (a sheet of slate and two glass filters) in the tanks, the fishes choose their territories according to a familiar view of these cues (Exp. 2, 7, and partly Exp. 3, 5, and 6). When, however, too strong counteracting cues reveal the positions of the new tanks in the experimental room (as manipulated with purpose in Exp. I) the fishes choose their territories according to these cues (Exp. 4 and partly so Exp. 3, 5 and 6), or possibly according to both kinds of cues, so that a random choice results (partly in Exp. 5 and 6). There are indications that relative territory choices can be imposed by former exposure to the territory area, and are further maintained in similar environments. Further experiments investigating related factors determining territory choice are suggested. A possible function of the demonstrated persistent territory choice effect is briefly mentioned.