substrates for optimal foraging in Caenorhabditis

Most animals inhabit environmentsin which resources are hetero-geneous and distributed in patches. A fundamental question in behavioral eco-logy is how an animal feeding on a particular food patch, and hence deplet-ing it, decides when it is optimal to leave the patch in search of a richer one. Optimal foraging has been extensively studied and modeled in animals not amenable to molecular and neuronal manipulation. Recently, however, we and others have begun to elucidate at a mechanistic level how food patch leaving decisions are made.1-3 We found that C. elegans leaves food with increasing probability as food patches become depleted. Therefore, despite its artificial laboratory environment, its behavior con-forms to the optimal foraging theory, which allowed us to genetically dissect the behavior. Here we expand our discussion on some of these findings, in particular how metabolism, oxygen and carbon dioxide regulate C. elegans food leaving behavior