Aims: 

We investigated effects of organophosphorus insecticide, ethyl parathion on survival, development and some biochemical parameters of endoparasitoid Pimpla turionellae (L.) reared on host insect, greater wax moth, Galleria mellonella (L.) pupae.

Methods: 

Newly hatched larvae of G. mellonella were orally exposed to 0.01, 0.1, 1.0 or 10 ppm of the insecticide by rearing on an artificial diet. The pupae emerged from these larvae were used as ethyl parathion-contaminated hosts for P. turionellae. As bioindicators of long-term physiological stress responses to such hosts, survival and development of the parasitoids were assessed. Furthermore alterations in activities of various enzymes involved in certain metabolic functions such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), acetylcholinesterase (AChE), acid phosphatase (ACP), lactate dehydrogenase (LDH), gamma glutamyl transferase (GGT), glucose-6-phosphate dehydrogenase (G6PDH), and content of total protein (TP) and lactate (LAC) were determined.

Results: 

Ethyl parathion did not significantly affect the survival while all tested concentrations caused significant increase in time required to reach fifth instar. Significant reduction in postlarval survival and increase in developmental time were obtained for high concentrations of the insecticide. Ethyl parathion significantly increased total protein content and activities of AST, ALT and GGT. The activities of ACP, AChE, and G6PDH were decreased by all concentrations of ethyl parathion. However, the insecticide at 0.1 ppm and above resulted in decreased lactate content and LDH activity.

Conclusion: 

This study infers that ethyl parathion-induced metabolic dysfunction is a causal factor in deterioration of survival and development of P. turionellae. Key words: Ethyl parathion, Pimpla turionellae, survival, transaminases, glucose-6-phosphate dehydrogenase, total protein.