Behavioural responses to radio-tag attachment in butterflies: Evidence for active tag removal

Radio telemetry is increasingly important in insect movement ecology, yet behavioural responses of insects to attached tracking devices remain poorly understood. Understanding such responses is essential for interpreting telemetry data accurately. We investigated whether butterflies exhibit active behavioural responses to radio tags by monitoring 89 individuals from eight tropical species under controlled indoor conditions and recording their flight behaviour using high-speed video. Among 39 Morpho helenor individuals, four males exhibited coordinated abdominal flexion and hind leg movements directed toward the tag antenna immediately after release. In two individuals, this manoeuvre resulted in successful tag dislodgement during flight, whereas in two others the tag remained attached despite repeated attempts. The observed removal behaviour in a subset of individuals demonstrates that compliance with proposed tag-to-body-mass thresholds alone does not guarantee passive tag tolerance and that behavioural responses should be considered when evaluating potential effects on flight behaviour and data quality.