The effect of ethanol on reversal learning in honey bees (Apis mellifera anatolica): Response inhibition in a social insect model

Abstract

We investigated the effects of ethanol on reversal learning in honey bees (Apis mellifera anatolica). The rationale behind the present experiment was to determine the species generality of the effect of ethanol on response inhibition. Subjects were originally trained to associate either a cinnamon or lavender odor with a sucrose feeding before a reversal of the conditioned stimuli. We administered 15 μL of ethanol at varying doses (0%, 2.5%, 5%, 10%, or 20%) according to group assignment. Ethanol was either administered 5 min before original discrimination training or 5 min before the stimuli reversal. We analyzed the effects of these three manipulations via a recently developed individual analysis that eschews aggregate assessments in favor of a model that conceptualizes learning as occurring in individual organisms. We measured responding in the presence of conditioned stimuli associated with a sucrose feeding, responding in the presence of conditioned stimuli associated with distilled water, and responding in the presence of the unconditioned stimulus (sucrose). Our analyses revealed the ethanol dose manipulation lowered responding for all three measures at increasingly higher doses, which suggests ethanol served as a general behavioral suppressor. Consistent with previous ethanol reversal literature, we found administering ethanol before the original discrimination phase or before the reversal produced inconsistent patterns of responding at varying ethanol doses.

Keywords: Classical conditioning; Ethanol; Honey bees; Individual analysis; Inhibition; Reversal.