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Why do some male moths have featherlike antennae with many olfactory sensilla?

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A pine grosbeak with pink and gray plumage perches on a branch, eating red berries among autumn foliage. — Chemoreception Animals, such as this pine grosbeak, use chemoreception to respond to chemicals that can be tasted and smelled in their environments. Many of these chemicals affect behaviors such as food preference and defense.

Some male moths possess featherlike (plumose) antennae to significantly increase their surface area, which allows them to accommodate a much higher number of olfactory sensilla compared to the slender antennae of females.12

This specialized structure is an evolutionary adaptation that provides the male with a high degree of sensitivity to pheromones released by females. Because the probability of detecting these chemical signals in low concentrations increases with the number of sensilla, these elaborate antennae enable males to locate potential mates from distances of several kilometers. For example, a male polyphemus moth may possess over 60,000 multiporous sensilla on a single antenna, facilitating the detection of female sex-attractant pheromones even when they are present in minute amounts in the environment.13