Suppression of Flight Activity by a Dopamine Receptor Antagonist in Honey Bee (Apis mellifera) Virgin Queens and Workers

Abstract

Dopamine (DA), one of the biogenic amines, has been suggested to regulate the motor activities of various animals. In honey bees, it has been reported to promote locomotor activity in queens, workers, and males, and to regulate the flight activity of workers and males. The role of DA in the flight activity of queens, however, has not yet been investigated. In this study, we tested the roles of DA in the flight activity of virgin queens. We first injected the DA receptor antagonist flupenthixol (10−2 M or 10−3 M) into the abdomens of 6-day-old virgin queens and measured the time to flight initiation. The same experiment was performed in workers, to confirm previous findings and compare them to the virgin queens. We then injected 10−2 M flupenthixol into the queens and quantified their flight activity using a flight mill. The workers were deemed unsuitable for this round of experimentation. In both queens and workers, flupenthixol injection significantly delayed flight initiation. In flight mill experiments, flupenthixol decreased the flight performance of the queens in terms of distance, duration, and velocity. These results suggest the involvement of DA in the flight activity of virgin queens and workers, and indicate that DA is a key neuroactive substance in motor system activation with conserved effects among honey bee queens, workers, and males.