Juvenile hormone III is an acyclic sesquiterpenoid that regulates diverse processes in insects, including adult transition of larvae and oogenesis in adult females. It activates the juvenile hormone receptor, known as methoprene-tolerant, with a Kd value of 2.9 nM. Juvenile hormone III can be synthesized from farnesoic acid by two alternative pathways, one through methyl farnesoate and the other through juvenile hormone acid III.