Effects of ligation on the cellular immune reactions of Drosophila algonquin against the hymenopterous parasite Pseudeucoila bochei.

When larvae of Drosophila algonquin parasitized by the hymenopterous parasite (parasitoid) Pseudeucoila bochei are ligatured early after infection so as to exclude the anterior endocrine center from the hemocytes and parasites located posterior to the ligature there is a decrease in the immune reaction rate. The data suggest that host endocrines are involved in the encapsulation and melanization reactions of the larvae, but the nature of the involvement is not known. The relationship between parasite encapsulation and melanotic tumor formation in Drosophila is discussed in terms of a possible common mechanism of activation.