Olfactory learning in the cricket Gryllus bimaculatus

The olfactory learning capability of the cricket Gryllus bimaculatus was studied. Crickets were deprived of drinking water for 4 days and were individually trained to associate peppermint with water and vanilla with NaCl solution. Their odour preference was tested before and after training by allowing them to choose between peppermint or vanilla sources. The time spent visiting each source served as a measure of odour preference. Crickets exhibited an initial preference for vanilla over peppermint, but preference for the latter increased after only one training session. The olfactory memory formed by a single training session decayed with time but remained for at least 24 h. Memory formed by three training sessions was extremely robust, and did not decay significantly between 1 and 7 days after training. The preference formed was easily altered by reversal training in which vanilla was associated with water and peppermint with saline solution. This study shows that crickets have a highly developed olfactory learning capability characterized by fast acquisition, long retention and easy rewriting of memory.