Hawkmoths Repeatedly Evolve Genitals to Foil Bat Attacks

WHO:

Phys.org - Male hawkmoths use specialized genital structures to produce ultrasonic sounds.

ScienceAlert - The research was led by entomologist Paul Masonick of the Florida Museum of Natural History.

ScienceAlert - Masonick and colleagues examined male hawkmoths from across the family.

WHAT:

Phys.org - Male hawkmoths rub specialized scales on their genitals against parts of their abdomens, producing ultrasound that may scramble bats’ hunting signals.

ScienceAlert - The ability to produce ultrasonic sounds with genital structures appears to have evolved independently as many as seven times over 30 million years.

ScienceAlert - Researchers identified at least three anatomical sound-making mechanisms: scales rubbing against scales, scales rubbing against tiny spines, and scales scraping across bumps called nodules.

ScienceAlert - The three mechanisms produce distinctive sounds, including rapid clicks, buzzes, or trills when slowed into the audible range.

ScienceAlert - Scale-on-scale mechanisms tend to produce shorter, intermittent bursts; scale-on-spine mechanisms produce longer, sustained sounds. Scale-on-nodule sounds vary considerably, including between closely related species.

ScienceAlert - The researchers’ study was published in *Proceedings of the Royal Society B: Biological Sciences*.

ScienceAlert - The study’s authors wrote: “Collectively, our findings deepen our understanding of defensive bioacoustic adaptations in this iconic predator-prey system.”

WHERE:

ScienceAlert - Researchers mapped sound-producing structures and behaviors onto the hawkmoth family tree.

WHEN:

ScienceAlert - The sound-producing ability evolved independently as many as seven times over a span of 30 million years.

WHY:

Phys.org - The sounds may interfere with acoustic signals bats use to hunt.

ScienceAlert - Sustained sounds were most likely to have characteristics associated with disrupting bat echolocation; shorter bursts may startle bats as they approach.

ScienceAlert - Researchers suggest the sounds might also mimic warning signals from toxic or unpleasant-tasting moths, or help some hawkmoths recognize their own species during courtship; the courtship possibility remains untested.

HOW:

ScienceAlert - Hawkmoths make sound through stridulation: specialized scales on genital structures called valvae move against modified abdominal surfaces.

ScienceAlert - Some hawkmoths can hear approaching bats’ ultrasonic calls and respond with noise; deaf species can produce ultrasound when touched.

(UPDATED November 4, 2026 21:10 UTC)

Male hawkmoths make ultrasound by rubbing specialized genital scales against their abdomens. The sounds may disrupt bats’ hunting signals or startle approaching predators. Researchers found this ability evolved independently up to seven times over millions of years.