A preliminary study of the polyembryonic cutworm parasite berecyntus Bakeri var. gemma Girault

Abstract

As early as 1923, the attention of Mr. K. M. King Was drawn to the occurrence in SasKatchewan of a hymenopterous insect parasite of the family Encyrtidae, Berecyntus bak.eri How. which was parasitizing noctuid larvae. Because of the great number of adults developing in a single host larva, it was thought that this parasite developed polyembryonically. A study of this insect was undertaken by the writer in 1927 at the suggestion of Mr. King, Since it was one of the major parasites of the red-backed cutworm (the most important cutworm occurring in Saskatchewan). This study was continued for three years, during which time much information concerning the parasite was secured. The data here presented indicate that Berecyntus bakeri develops in a polyembryonic fashion, the stage in which parasitism initially occurs being the host egg. The various stages in its development are somewhat similar to those described by Leiby for Copidosoma Gelechiae How., but there are striking differences also exhibited, not only with the former species but with other polyembryonic species. Such are to be expected since the development of only a few polyembryonic species have been described and since each of these differs essentially from any other.