Resource heterogeneity but not inbreeding affects growth and grouping behaviour in socially foraging juvenile cichlid fish

1. Spatial food distribution determines resource profitability, defensibility and encounter rate of foragers. Clumped food distribution can promote aggressiveness and resource monopolisation, in turn increasing within-group variation in food intake and growth. However, the effects of food distribution may depend on foraging strategies. Little is known about the impact of spatial food heterogeneity on growth and grouping behaviour in social foragers in the absence of monopolisation.

2. Social foraging is present in many fishes, particularly at early juvenile life stages when fish are especially sensitive to environmental variation. Here, a heterogeneous food distribution may impair foraging success and growth and juveniles may increase sociability to attain social information about food resources.

3. We examined the impact of the spatial distribution of food as well as inbreeding on growth and social behaviour in juveniles of the cichlid fish Pelvicachromis pulcher. Inbred individu...