Nutrient-specific learning in an omnivorous insect: The American cockroachPeriplaneta americana L. learns to associate dietary protein with the odors citral and carvone

Experiments were performed to test for nutrient-specific olfactory learning in the American cockroach, Periplaneta americana L. In a conditioning peri od, cockroaches were presented with two complementary foods, one of which c ontained protein and the other carbohydrate, this combination allowing them to select a nutritionally balanced diet. The foods were separated in space , and each was paired with one of two odors, citral or carvone. The cockroa ches were then selectively deprived of one of the nutrients for 24 or 48 h. In the final (test) phase of the experiment the movement of the cockroache s toward the nutrient-associated odors wets monitored. Associative learning was demonstrated with respect to protein, with protein-deprived cockroache s moving more frequently toward the protein-associated odor. No learned ass ociations between carbohydrate and odor were demonstrated. These data are c ontrasted with similar experiments on an herbivorous insect, the locust Loc usta migratoria.