Why do insects often rely on smell and touch during courtship?

In the study of reproductive behaviour, insects frequently rely on smell and touch during courtship because these modalities are highly effective for species-specific communication and synchronization, which are essential for successful mating.1

Olfactory Signaling

Insects often utilize pheromones to advertise their readiness to mate, attract potential partners, and ensure species recognition. Because these chemical signals can be highly specific, they help prevent cross-mating between different species, which would otherwise result in a waste of reproductive resources. For example, male monarch butterflies use specialized structures to dust pheromones onto a female's antennae, inducing her to permit copulation.12

Tactile Signaling

Tactile signals are crucial for coordinating the physical act of mating and reducing hostility between partners. Because many insects and other animals possess an aversion to bodily contact—often as an antipredator mechanism—courtship behaviors involving touch help appease partners and synchronize the release of gametes. Furthermore, tactile interactions, such as those involving substrate-borne vibrations or physical contact, allow insects to identify mates and assess their quality in environments where visual or auditory signals may be less effective.13