STUDIES ON THE NUTRITIONAL STATE AND THE RESPONSE TO AGGREGATION PHEROMONES IN THE BARK BEETLE, IPS-TYPOGRAPHUS (L) (COL, SCOLYTIDAE)

The correlation between nutritional state and behaviour was studied in an overwintering population of bark beetles, Ips typographus (L.). It was found that 3 groups of the bark beetles could be distinguished wi th respect to their nutrient contents and reactivity to the traps with aggregation pheromone in the field. Group A - newly emerged beetles s earching for food ignored the pheromone traps, were shown to have low protein and glycogen contents. Group B - feeding beetles with high lip id and glycogen contents but relatively low protein content probably d ue to degeneration of flight muscles. They were taken as control with regard of nutrient contents. Group C - beetles, attracted to the phero mone traps, were divided into two subgroups: C1 - beetles with high co ntent of glycogen and lipid but low protein. They represented about 25 -30 % of captured beetles and they were from local population. C2 - ch aracterized by a low content of glycogen and lipid but high protein, p robably due to well developed flight muscles. They represented about 7 0 % and probably belonged to migrating beetles. A possible correlation between reactivity to pheromones and nutrient reserves is discussed.