Apis dorsata drone flights, collection of semen from everted endophalli and instrumental insemination of queens

Abstract

We observed drone flights of 16 colonies of Apis dorsata in Chitwan, Nepal. At the end of February drone flights occurred between 18:15 and 18:35 h. By April, as day length increased, drones flew gradually later. Within 2 months the start of drone flights was delayed by 42 min. High correlation (r = 0.99) was found between the sunset time and the start of drone flights. After the thorax or abdomen of drones were squeezed, seven stages of endophallus eversion occurred. Semen appeared as a small drop at the ventral side of completely everted cervix. We collected 8 mm3 of semen from 41 drones. Thus, one drone produced on average 0.2 mm3 of semen. Three Apis mellifera queens were inseminated with 2-3 mm3 of A. dorsata semen. All queens started to lay eggs. Larvae hatched from 3% of eggs. After sealing of the larvae, only drone pupae were found. We speculate that embryos in rest of the eggs did not develop due to genetic incompatibility.