Animals don’t always advertise for mates through courtship displays or courtship rituals. Many other methods are available. For instance, many species secrete chemicals known as
pheromones that can travel through air or water, and that indicate an individual’s sexual status. In many moth species, for example, sexually-receptive females release pheromones which males can detect and home in on from considerable distances.

The antennae of a male Luna Moth (Actias luna
) are extremely
sensitive to pheromones produced by sexually-receptive females.