Wstępne badania nad oddziaływaniem międzygatunkowym u Calandra Granaria L. (Coleoptera, Curculionidae) i Oryzaephilus Surinamensis L. (Coleoptera, Cucujidae)

Abstract

The paper is a component part of a more extensive research on the interaction between the populations of several species of beetles, stored pests. More specifically, it concerns the interaction between Calandra granaria and Oryzaephilus surinamensis. The methods of research have been founded on the fact that both these species have marked migratory ability. In receptables containing wheat, rice, and rice mixed with wheat, 40 specimens of each sub-species were included (in control receptables, 80 specimens of one species in each receptable). The receptables were put in a position which permitted the insects to migrate freely from one to another. Experimental results obtained by controlling the numbers of imagines during the full growth of the population (i.e. after two and a half months have elapsed) have allowed to establish that Calandra granaria exerts a stimulating effect upon the development of the population of Oryzaephilus surinamensis. On the other hand, the effect exerted by Oryzaephilus surinamensis upon Calandra granaria is of competitive type, and consists in reducing the numbers of the latter species.