Temperature distribution and electrical properties along the Oriental hornet body.

The hornet is an endothermic insect. Daily variations in hornet surface temperature were measured. Three peaks were found between 9:30 and 10: 30 a.m., 11 and 12 a.m. and between 2 and 3 p.m. Electrical current and voltage values were highest along the head. Electrical current along the gaster and the head flowed towards the thorax, i.e., from body parts with minimal temperature towards the body part with maximal temperature. Current and voltage values measured across the cuticle of the gaster were about 5nA and 100 mV, respectively, and these were of the same order of magnitude as the current and voltage values along the cuticle. It was found that: 1) temperature regulation most probably originates in the thorax and 2) there is a correlation between the temperature distribution along the hornet body surface and levels of the cuticular electrical signals.