This study deals with voltage values recorded off the cuticle of live specimens of the Oriental hornet Vespa orientalis (Hymenoptera, Vespidae). The relevant measurements were taken between the two tips of their bodies at various hours of the day and were made on a total of 90 worker hornets. Recorded voltage values varied within a range of 60-180 mV, with the lower values measured during the morning hours and the afternoon and the highest values during the noon hours. Measurements were made by direct contact of the electrodes with the hornet cuticle and did not prove lethal to the measured specimens. An additional 60 live hornets were measured in the same fashion but in the dark. The values recorded in the dark varied between 40 and 70 mV and displayed considerable fluctuations but were not found to be dependent on the time of measurement. The distribution of the voltage values in hornets measured at various hours in the daytime closely resembled that of the global radiations (in W/m2) on the same days the measurements were taken.

In the cuticle of live social hornets, such as Vespa orientalis (Hymenoptera, Vespinae), endogenous electric effects are encountered, i.e. voltages of 100-200 mV under illumination and currents amounting to several microamperes on its subjection to darkness-clearly a process of charging and discharging. Of the various wavelengths of sunlight, UV was found to be the most contributory to the active cuticular voltage generation. Throughout the warm season of the year--the active period in colonies of social hornets and wasps--colony members exit from the dark nest during the daytime and fly to the field under the hot sun for various foraging purposes, ultimately returning to the nest. Thus, each hornet, be it queen, worker or drone, probably undergoes daily cyclical process of electric charge and discharge in the exterior part of their integument, cuticle, which lasts up to 30-40 min. Such photoelectric phenomenon was detected in both live, ether-anaesthetized hornets and dead hornets, albeit in the latter the electric values recorded were lower. The present study addresses the possible impact of the phenomenon on vespan daily life and also compares it with a parallel occurrence in electric fish.

In the cuticle of live social hornets, such as Vespa orientalis (Hymenoptera, Vespinae), endogenous electric effects are encountered, i.e. voltages of 100-200 mV under illumination and currents amounting to several microamperes on its subjection to darkness4learly a process of charging and discharging. Of the various wavelengths of sunlight, UV was found to be the most contributory to the active cuticular voltage generation. Throughout the warm season of the yearthe active period in colonies of social hornets and waspscolony members exit from the dark nest during the daytime and fly to the field under the hot sun for various foraging purposes, ultimately returning to the nest. Thus, each hornet, be it queen, worker or drone, probably undergoes daily cyclical process of electric charge and discharge in the exterior part of their integument, cuticle, which lasts up to 30-40 min. Such photoelectric phenomenon was detected in both live, ether-anaesthetized hornets and dead hornets, albeit in the latter the electric values recorded were lower. The present study addresses the possible impact of the phenomenon on vespan daily life and also compares it with a parallel occurrence in electric fish.

This study deals with voltage values recorded off the cuticle of live specimens of the Oriental hornet Vespa orientalis (Hymenoptera, Vespidae). The relevant measurements were taken between the two tip of their bodies at various hours of the day and were made on a total of 90 worker hornets. Recorded voltage values varied within a range of 60‐180 mV, with the lower values measured during the morning hours and the afternoon and the highest values during the noon hours. Measurements were made by direct contact of the electrodes with the hornet cuticle and did not prove lethal to the measured specimens. An additional 60 live hornets were measured in the same fashion but in the dark. The values recorded in the dark varied between 40 and 70 mV and displayed considerable fluctuations but were not found to be dependent on the time of measurement. The distribution of the voltage values in hornets measured at various hours in the daytime closely resembled that of the global radiations (in W/m2) on the same days the measurements were taken.

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