POLYVARIANCE OF HARPALUS (S. STR.) AFFINIS SCHRANK AND ITS ADAPTIVE SIGNIFICANCE

On the basis of field experiments in Southwest Moldova, specific featu res of the Harpalus (s. str.) affinis Schrank life cycle are discussed . In the steppe zone, the seasonal dynamics of activity of this specie s features two peaks. Spring activity is determined by overwintering i mmature individuals. In early June, mature beetles are most abundant, while in the middle of August, spent beetles predominate. The autumn p eak of activity is determined by teneral specimens. They are most abun dant in early September, while the maximal number of the corresponding immature beetles is observed in late September. A noticeable time bre ak between the appearance of immature individuals and the absence of m ature beetles in August-September suggest that the autumn peak beetles are descendants of the spring beetles. The data on H. affinis breedin g in the laboratory also confirmed this hypothesis. Hence, the life cy cle of H. affinis is realized in this case to be annual with overwinte ring image. Single spent beetles can also overwinter and take part in breeding during the next season. However, the data of soil excavations suggest that the older instar larvae and pupae can also overwinter. T heir keeping showed that the period of rest is significantly extended. The moulting of the overwintered 2nd instar larvae into the 3rd insta r ones was observed only in late June and in the pupae, in late July. The 3rd instar larvae captured in early May pupate only in late July. Development of the pupae lasted from July until August. Mass hatching of young beetles was observed at the middle to the end of August. The overwintered pupae had the longest development (100 to 104 days). The emergence of young beetles in this case also coincides in time with th e appearance of image originating from the eggs laid by the overwinter ed beetles. Therefore, the life cycle of H. affinis is also realized i n the biannual variant. On the whole, the life cycle of this species s hould be characterized as polyvariant with a spring breeding period, s pring-autumn activity image, and multiseasonal larval activity. Polyva riance of the life cycle is of great adaptive significance. The older the population, the more ''formal groups'' of individuals it contain's . This enables intense exchange of genetic information within the popu lation, prevents elimination of local populations, and ensures surviva l of the species during unfavorable periods and large-scale habitat ch anges.