Electrostatic measurement of dischargeable electricity and bioelectric potentials produced by muscular movements in flies

•We developed a simple electrostatic apparatus to capture flies.•Attraction of flies was stable enough to consecutively trace the muscular movements.•We measured dischargeable electricity and bioelectric potentials produced by flies.•A tail-lifting movement by the insect was an action creating electric potentials.•The discharge was larger at higher elevation angles of the lifted tail tip.

A simple electrostatic apparatus was devised to measure dischargeable electricity and bioelectric potentials produced by flies. The apparatus involved two insulated electrodes, ICW(−) and ICW(+), oppositely charged with equal voltages supplied by two voltage-generators. In the electric field, the flies became net positive by instantaneously discharging their electricity and were attracted to negative surface charges on ICW(−). The tail-lifting movement by the attracted insect was an action creating electric potentials that could cause discharge of ICW(−). The discharge transiently appeared in response to individual movements and was larger when the tail was lifted at higher angles.