MUTUAL TRAINING OF FRUIT-FLIES IN THE GRO UP SITUATION BY TRIAL-AND-ERROR METHOD

In the group situation, fruit flies try to avoid conflicts in which th ey kick each others. At first they attempt to escape from each other t hus increasing run frequency as compared with control solitary individ uals, but shortly terminate runs in order to prevent collisions. Motor ic activity and conflict frequency during encounters are high in such situations. From the very beginning, probability of transition from ac tivity to direct contact is higher than that from rest to contact or f rom preening to contact. Therefore, during the first 5 minutes a fly l earns to increase interval between runs using the trial-and-errormetho d. Besides abrupt decreasing of number of collisions and activity of f lies in group as compared with control, operant training leads to form ation of passive aggregations, because closely situated flies avoid to display activity. A new behavior reaction is developed, as well, name ly immobile fly initiate preventive touches by legs. Such training is adaptive because in the natural aggregations of flies on fermented fru its it increases aggressive activity decreasing thus raising efficienc y of feeding on a common substrate.