A critical look at the currencies of optimal foraging theory: should nitrogen be considered?

Abstract

Optimal foraging models focus on energy as the main unit of currency. Here, we tested for preferential foraging of Formica spp. for sucrose, casein hydrolysate, and both solutes combined in field studies. Statistical analyses using two-way analysis of variance (ANOVA) and least significant difference (LSD) tests, indicate that Formica spp. preferentially forage for sucrose. Our results also indicate a significant interaction between sucrose and casein hydrolysate in solutions containing both. Models for preference are suggested.