Wax moths: ultrasonic hearing and potential pest control

Both Galleria mellonella and Achroia grisella, known as greater and lesser wax moths, respectively, are damaging to the apiculture industry. Wax moths lay their eggs on bee hives and, upon hatching, their larvae feed on various products of the bee colony and dig tunnels, sometimes causing so much damage that the bees end up abandoning the hive completely. A sustainable but efficient pest control technique that does not harm bees or other non-targeted species is desirable for managing wax moth pests. Their ultrasonic hearing, characteristic of both species and used for bat avoidance, is exploitable for pest control. Additionally, the lesser wax moth presents sound-mediated courtship and monoaural directional hearing, unusual in moths. Firstly, the greater wax moth’s (the most damaging of the two) neural response is studied, using broadband ultrasound to determine peak sensitivity and common Japanese bats’ temporal patterns of echolocation; an optimal ultrasonic signal for deterrence is thus determined. Secondly, the lesser wax moth’s directional hearing is studied through finite element modelling, aiming to capture its essential features in a simplified model of its eardrum and explain its monoaural directional hearing. Both of these results contribute to a better understanding and management of wax moth pests.