Acoustic phenotyping reveals sublethal pesticide stress in bees using BEEhaviourLab

Behavioural responses often provide the earliest detectable signs of physiological stress yet quantifying them at scale remains challenging. Acoustic behaviours such as buzzing are central to insect locomotion and communication but are rarely measured systematically, and their potential as sensitive indicators of environmental stress remains largely unexplored. Here, we test whether changes in insect acoustic behaviour can reveal sublethal effects of pesticide exposure. Using a newly developed automated behavioural platform (BEEhaviourLab), we recorded synchronised video and audio from insects, enabling simultaneous, high-throughput quantification of locomotor activity and buzzing behaviour across multiple individuals and species without the need for tagging. We applied this system to characterise the effects of the veterinary antiparasitic moxidectin on the bumble bee Bombus terrestris. Acute contact exposure produced dose-dependent reductions in locomotion and buzzing behaviour at concentrations below lethal thresholds. Acoustic measures detected behavioural disruption with sensitivity comparable to video-based activity metrics, demonstrating that buzzing behaviour provides a sensitive and previously unused indicator of neurotoxic stress. More broadly, scalable multimodal behavioural phenotyping enables subtle behavioural disruption to be detected across large experiments, opening new opportunities to incorporate acoustic endpoints into studies of animal behaviour, environmental stress, and ecological risk assessment.