Under harsh environmental conditions, larvae enter a developmentally arrested state known as dauer; TGF-beta-like daf-7 acts to inhibit dauer larva formation and promote growth (PubMed:8910282). May be a ligand to cell surface receptor daf-4 (PubMed:8413626). May act as a negative regulator of dauer larva development by transducing chemosensory information from ASI neurons (PubMed:8910282). Involved in sensitivity to CO2 levels (PubMed:18524955). Involved in mate searching behavior of males, acting in concert with the neuropeptide pdf-1 (PubMed:30024377). In AWC neurons, acts to promote expression of srsx-3, a member of the GPCR family (PubMed:20713521). Expressed in the chemosensory neurons, including in the ASJ neurons in males. When the food/pheromone ratio is high, its level peaks during the L1 larval stage (PubMed:8910282). Expression is detected in larvae beginning 4 to 5 hours after hatching, through the four larval stages, and in adults (PubMed:8910282). Expressed in ASJ chemosensory neurons in males from the L4 larval stage (PubMed:31264582). Dauer-inducing pheromone inhibits its expression and promotes dauer formation, whereas food reactivates its expression and promotes recovery from the dauer state. Belongs to the TGF-beta family.