The effects of host metal stress on a parasitoid in an insect/insect relationship (Lymantria dispar L., Lymantriidae Lepid. : Glyptapanteles liparidis Bouche, Braconidae Hym.)

A host-endoparasitoid relationship was investigated under metal stress. Lymantria dispar (gypsy moth) larvae were reared on artificial diets contaminated with two concentrations of cadmium (2 and 10 mu g/g), lead (4 and 20 mu g/g), copper (10 and 50 mu g/g) and zinc (100 and 500 mu g/g), all based on dry weight. Following parasitization in the first premoulting period by Glyptapanteles liparidis, the eclosal success of G. liparidis and the developmental rates of both species were investigated and compared with controls. Additionally, metal concentrations were monitored in host individuals and parasitoids by flame and flameless AAS. The developmental rate of the endoparasitoid positively correlated with that of the host. A negative relationship was found between the number of closed G. liparidis and the developmental rate of the host. No correlation was found between the extent of metal contamination and parasitization success. Correlation of results led to the conclusion that the elevated metal concentrations did not affect G. liparidis directly, but that parasitoid development is more likely to be influenced by alterations in the trophic situation within the host larvae due to metal stress.