Involvement of octopamine in conditioned visual flight orientation in honeybees

Abstract

Abstract Visual orientation learning of a tethered flying bee was investigated using a flight simulator with a novel protocol using which orientation preference tests were performed before and after classical conditioning was applied. Either a blue or a green rectangle (conditioned stimulus, CS) was associated with 30% sucrose solution (unconditioned stimulus, US), whereas the other was not paired with US. Bees were tested in a closed-looped flight simulator 5 min after ten pairing presentations of US and CS. Conditioned bees preferentially oriented to the CS compared to the other color. This increase in the preference for CS was maintained for 24 h, indicating that long-term memory was established by this procedure. Because the total flight time was not altered by the conditioning, conditioning did not enhance orientation activity itself but increased the relative time for orientation to CS. When 0.4 or 4 mM epinastine (an antagonist of the octopamine receptor) was injected into the bee’s head 30 min prior to the experiment, both short- and long-term memory formation were significantly impaired, strongly suggesting that octopamine, which is crucial for appetitive olfactory learning in insects, is also involved in visual orientation learning.