Foraging Under Predation - a Comparison of Energetic and Predation Costs in Rodent Communities of the Negev and Sonoran Deserts

摘要: We used patch-use theory, giving-up densities in experimental food patches, and harvest-rate measurements within these patches to determine the relative contributions of predation risk energy foraging costs four species rodents from communities Sonoran Negev deserts. To partition into components predation, we converted field harvest rates (J min(-1)), as an estimate total costs, estimated energetic published physiological activity thermoregulatory assumed that missed opportunity were either zero or negative. Our results showed predominate. Energetic represented only 24%, 19%, 16% 13% for Merriam's kangaroo rat (Dipodornys merriami; Sonoran), round-tailed ground squirrel (Spermophilus tereticaudus; greater Egyptian sand gerbil (Gerbillus pyramidum; Negev), Allenby's (G. allenbyi; respectively. Equally important predation-risk differences between bush open microhabitats; microhabitat cost often 2-4 times larger than animals' costs. Seasonal patterns also predominantly influenced by rather Predation appear be Desert, but desert experience seasonal variability As a result, may contribute more towards coexistence community Desert Desert.