Darwin's hawkmoth (Xanthopan morganii praedicta) emits ultrasound at bat sonar-jamming rates

In 1862 Charles Darwin received an orchid gift from Madagascar with a 30cm nectary and predicted the existence of a moth with a similar-length tongue to pollinate it. Decades later, the Madagascan moth that fit this description was found: Xanthopan morganii predictae. Since its discovery to Western science, X. morganii has spurred research and lively debate regarding the coevolutionary dynamics between pollinator and plant. Xanthopan morganii also holds the promise of a different and equally fascinating coevolutionary story - that of predator and prey. As these hawkmoths fly at night to find mates or hover in front of a flower to forage, they must also evade bat attack. Many hawkmoths have an anti-bat arsenal at their disposal, with mouthpart-based bat-detecting ears and genital-driven sound-producing structures. Ultrasonic sound production in moths can function to startle, warn bats of bad taste, or to jam bat sonar. Previous work with X. morganii has shown that they make ultrasonic responses to bat attack cries, but little was known about its sounds. Using a diverse array of recorded bat calls, I tested X. morganii’s anti-bat response and found that it produces an intense acoustic return. With an average duty cycle (sound per unit time) of ~30%, X. morganii is likely capable of jamming bat sonar. I discuss these findings in context of other sound-producing moths and provide questions for future testing. X. morganii continues to provide a window into the natural world and illuminate evolutionary tensions that have driven traits across time.