BIONOMICS OF TRIOXYS INDICUS, AN APHIDIID PARASITOID OF APHIS CRACCIVORA. X. SUPERPARASITISM CAUSED BY CONFINEMENT WITH THE HOST

Superparasitism in Aphis craccivora by Trioxys indicus was observed in the field and in the laboratory. A parasitoid which is ready to oviposit will not so readily lay eggs in parasitised hosts and search-deterring substances may reduce superparasitism. As the number of parasitised hosts in a container increases, the "escape" attempts of the parasitoid are more frequent. After a period of preening and standing-still, the parasitoid returns to the leaf, begins to encounter, prick, and probe the hosts again; the escape tendency apparently decreases. These activities either lower the oviposition threshold or overcome it resulting in superparasitism.