9(Z)-Pentacosene is a cuticular hydrocarbon and insect sex hormone. It is found in the cuticle of female F. canicularis flies and is an attractant to males in a trap assay. 9(Z)-Pentacosene is a contact sex hormone in scarab beetles and locust borers that is more abundant in females than males. It elicits arrestment, alignment, and mounting by males of both species in mating assays but only elicits copulation by the locust borer. 9(Z)-Pentacosene is also produced by the orchid O. exaltata and by C. cunicularius, a pollinator of O. exaltata.
