INHIBITION OF DEFENSE REACTION OF DROSOPHILA MELANOGASTER PARASITIZED SIMULTANEOUSLY BY WASPS PSEUDEUCOILA BOCHEI AND PSEUDEUCOILA MELLIPES

The encapsulation reaction normally elicited by the wasp Pseudeucoila mellipes in Drosophila melanogaster fails to occur in hosts parasitized simultaneously or shortly afterwards by resistant Pseudeucoila bochei, but occurs as usual in hosts parasitized by P. bochei that are themselves susceptible to encapsulation. The protection from encapsulation afforded to P. mellipes by P. bochei in the same host is attributed to an active mechanism by which P. bochei protects itself from encapsulation. The possible role of substances elaborated by the wasp egg or female in preventing a successful host reaction is discussed. © 1969.