SUPERPARASITISM BY <em>TRICHOGRAMMA</em> <em>POLIAE</em> IN THE EGGS OF <em>CLOSTERA</em> <em>CUPREATA</em> (LEPIDOPTERA: NOTODONTIDAE) AND ITS EFFECT ON OFFSPRING

Abstract

The paper describes the occurrence of "superparasitism" in the eggs of the poplar defoliator, Clostera cupreata, and in the laboratory host, Corcyra
cephalonica, by the egg parasitoid, Trichogramma poliae. Superparasitism was determined by exposing host eggs and parasitoids in different numerical combinations and observing the number of offspring emerging from individual superparasitised eggs. The effect of superparasitism on the body size of emerged individuals was also determined. When the parasitoid:host ratio was 2:1, the incidence of superparasitism in the eggs of C. cupreata was 90% with an average number of 5.44 offspring developing per egg, and 40% in the eggs of C. cephalonica, with an average of 2.33 individuals per egg. Superparasitism declined markedly with increase in the relative availability of host eggs. Average body length of offspring obtained from superparasitised eggs of C. cupreata ranged from 0.34 to 0.39 mm for females and 0.25 to 0.27 mm for males in
comparison with a mean body length from non-superparasitised eggs of 0.52 mm and 0.41 mm respectively. Similar reductions in size were observed in offspring from superparasitised eggs of Corcyra cephalonica. An inverse relationship between numerical emergence and body length of the parasitoid was also observed from superparasitised eggs of C. cupreata.