BEHAVIORAL-ANALYSIS OF OLFACTORY CONDITIONING IN THE MOTH SPODOPTERA-LITTORALIS (BOISD.) (LEPIDOPTERA, NOCTUIDAE)

We studied the associative learning capabilities for behaviourally rel evant cues in the moth Spodoptera littoralis. The moths were trained t o associate a conditioned stimulus (CS), geraniol odour, with an uncon ditioned stimulus (US), a sucrose solution. The occurrence of a probos cis extension reflex (PER) was tested. The PER performance during acqu isition increased steadily with the number of training trials. Non-ass ociative control procedures did not result in learning. PER conditioni ng was achieved when the CS was presented 1-3 s before the US. A wide range of inter-trial intervals was able to support conditioning. Males and females learned equally well. Moths could to some degree learn th e CS-US association after a single trial. These results demonstrate th at S. littoralis females and males have a good capability to associate an odour with a reward. The neural basis of olfactory coding in moths has been well studied; thus, the moth provides a powerful system in w hich to examine the neurobiology of olfactory learning.