Relationships between trophic niche breadth and reproductive capabilities in a population of Proasellus coxalis Dollfus (Crustacea: Isopoda)

Single, ovigerous females of Proasellus coxalis Dollfus, collected from a natural population, were experimentally assessed for five characteristics: food niche breadth; ingestion rate; vagility among resource patches; brood size; and body size. Reproductive efficiency was evaluated as brood size divided by ingestion rate. Large individuals had greater mean brood sizes than smaller individuals and generalist individuals had brood sizes greater than specialists. By contrast, the reproductive efficiency of generalists was less than that of specialists and this was ascribed to greater vagility and hence foraging costs associated with the generalist habit.