Male Moths Create Fragrances from Flowers to Entice Females

Male tobacco budworm moths have been found to collect perfume from flowers and emit it while courting females in order to make themselves more attractive. While it is well-known that female moths release scented chemicals to attract males, less is known about how males use scents to entice females.

Coby Schal and his colleagues at North Carolina State University discovered that male tobacco budworm moths, which are a major agricultural pest, collect a plant scent called methyl salicylate and use it to increase their mating success. Methyl salicylate is found in the flower nectar of various plants and has a sweet, minty odor that attracts insects.

In their study, the researchers measured the levels of methyl salicylate in male moths that were reared on a synthetic diet in a laboratory, as well as in moths collected from a soybean field. They found that lab-reared males had low levels of the chemical, while field-collected males had high levels, suggesting that they had obtained it from the crop plants.

During courtship, the male moths released the methyl salicylate from their hair pencils, which are hairy-tipped appendages that emit a range of chemicals for communication. The researchers also discovered that the antennae of female moths have two receptors that are tuned to detect methyl salicylate. When the male moths had their hair pencils removed, their mating success dropped by approximately 30 percent.

These findings suggest that male moths use their hair pencils to emit methyl salicylate, which females are naturally attracted to in plants, as an “aphrodisiac” to increase females’ sexual receptivity. This behavior has also been observed in orchid bees, where males collect perfume from orchid flowers and use it to attract females.