Temporal patterns of seed use and availability in a guild of desert ants

摘要: . 1 Temporal patterns of seed use were studied from late winter to autumn in three species seed-harvesting ants the Sonoran Desert. Measures effective foraging activity, dietary niche breadth and overlaps obtained each month tested for correlation with estimates available resource. 2 Seeds only numerically important type food diets all species. 3 The partitioned resource according both size, although there was considerable overlap. 4 Pheidole xerophila had smallest forager body size is a specialist on small seeds because it harvested them greater proportion than their rank soils expanded its diet larger when abundance declined. 5 When Bouteloua barbata decreased, middle-sized ant, Veromessor pergandei, showed decrease increase breadth, overlap P.xerophila. 6 Seed preferences V.pergandei did not vary seasonally, except that during highest abundance, no preference. 7 Pogonomyrmex rugosus largest ant; preferred inactive most abundant. Seasonal activity parameters random relation abundance. 8 We suggest nocturnal by P.rugosus summer months response interference diurnal either predation frorn horned lizards or competition V.pergandei. 9 Seasonal explains seasonal P.xerophila V.pergandei. The summertime years adequate precipitation may account P.rugosus.