IN VITRO STUDY OF PHYSIOLOGICAL SUPPRESSION OF SUPERNUMERARY PARASITES BY THE ENDOPARASITIC WASP LEPTOPILINA HETEROTOMA

In superparasitized larvae of Drosophila melanogaster, supernumerary eggs of the wasp parasite Leptopilina heterotoma were destroyed prior to the hatching of the single dominant egg. When cultured indi- vidually in Shields and Sang's Medium, 81% of 30-hr-old dominant eggs developed successfully and hatched. However, when 2 dominant eggs were cultured together, the development of 1 or both of the paired eggs was inhibited in 91% of the cases. It is proposed that the dominant eggs of Leptopilina heterotoma produce a substance that suppresses the development of supernumerary parasites. Endophagous insect parasites (parasitoids)