EUROPEAN JOURNAL OF ENTOMOLOGY

Eur. J. Entomol. 94 (3): 409-420, 1997

Host-parasitoid relationship of Ceratitis capitata (Diptera: Tephritidae) and Coptera occidentalis (Hymenoptera: Proctotrupoidea: Diapriidae) under host heavy metal stress

KAZIMIROVA M., SLOVAK M., MANOVA A.

N/A

The development and fecundity of Ceratitis capitata Wiedemann (Diptera: Tephritidae) and the host-parasitoid relationship of C. capitata and its pupal endoparasitoid, Coptera occidentalis (Muesebeck) (Hymenoptera: Proctotrupoidea: Diapriidae) were investigated under conditions in which the host was stressed by heavy metal ingestion. C. capitata larvae (from first instar to pupation) were fed diets that were separately contaminated with three metals; each contaminant was applied at four concentrations that differed by a factor of 2. The lowest concentrations were as follows: copper 100 µg/g, cadmium 25 µg/g and lead 100 µg/g diet dry weight (dw). Larval development, pupation rate and pupal weight of the fruit fly were negatively affected by increasing metal concentrations. Metal concentrations of 400 µg Cu, 50 µg Cd and 400 µg Pb/g diet dw were selected for studying reproductive performance of C. capitata and parasitisation rate, development and reproduction of C. occidentalis. Oviposition, actual fecundity and hatching rates of C. capitata were not significantly influenced by metal contamination. The parasitoid did not discriminate between metal-contaminated and control fruit fly pupae. Parasitisation rates were similar in all treatments (64.6-65%). Heavy metal induced stress of the host altered neither the parasitoid developmental rate nor the proportion of females in parasitoids that emerged from contaminated pupae. Life span and reproductive performance of C. occidentalis females that emerged from metal-stressed hosts were not significantly different from control females. However, a significantly lower percentage of females emerged from copper-and cadmium-contaminated hosts. In groups contaminated by 400 µg Cu, 50 µg Cd and 400 µg Pb/g diet dw, whole body concentrations of the respective metals were determined in pupae and imagines of C. capitata and imagines of C. occidentalis.

Keywords: Insects, Ceratitis capitata, Coptera occidentalis, pupal parasitoid, development, fecundity, heavy metals, copper, cadmium, lead

Accepted: March 3, 1997; Published: July 30, 1997  Show citation