1D-02 Insulin-like signaling functions in association between temperature and feeding state in C.elegans

C. elegans shows behavioral plasticity in response to environmental changes. Well-fed animals show attraction but starved animals show avoidance to their cultivation temperature on a thermal gradient. ins-1 mutants which have a deficit in insulin homologue migrated to cultivation temperature regardless of the feeding experience (Aho; Abnormal hunger orientation phenotype), and were normal in feeding state-dependent locomotory activity. These results suggest that ins-1 mutants are likely to be defective in associating temperature and feeding state. daf-2, age-1 and daf-16 encode homologues of insulin receptor, PI3 kinase, and forkhead-type transcriptional factor, respectively. daf-2 mutants and age-1 mutants did not show Aho phenotype, but daf-16 mutants showed weak Aho phenotype. Further, the daf-2 mutation weakly suppressed the ins-1 mutation： ins-1; daf-2 double mutants showed weaker Aho phenotype than ins-1 mutants. Our results are consistent with the possibility that ins-1 acts upstream of daf-2 and negatively or antagonistically affects on insulin-like signaling pathway required for the association mechanism between temperature and feeding state.