HOST-PARASITOID RELATIONSHIP OF CERATITIS-CAPITATA (DIPTERA, TEPHRITIDAE) AND COPTERA-OCCIDENTALIS (HYMENOPTERA, PROCTOTRUPOIDEA, DIAPRIIDAE) UNDER HOST HEAVY-METAL STRESS
M. Kazimirova et al., HOST-PARASITOID RELATIONSHIP OF CERATITIS-CAPITATA (DIPTERA, TEPHRITIDAE) AND COPTERA-OCCIDENTALIS (HYMENOPTERA, PROCTOTRUPOIDEA, DIAPRIIDAE) UNDER HOST HEAVY-METAL STRESS, European journal of entomology, 94(3), 1997, pp. 409-420
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) (Hymenopte
ra: Proctotrupoidea: Diapriidae) were investigated under conditions in
which the host was stressed by heavy metal ingestion. C. capitata lar
vae (from first instar to pupation) were fed diets that were separatel
y contaminated with three metals; each contaminant was applied at four
concentrations that differed by a factor of 2. The lowest concentrati
ons were as follows: copper 100 mu g/g, cadmium 25 mu g/g and lead 100
mu g/g diet dry weight (dw). Larval development, pupation rate and pu
pal weight of the fruit fly were negatively affected by increasing met
al concentrations. Metal concentrations of 400 mu g Cu, 50 mu g Cd and
400 mu g Pb/g diet dw were selected for studying reproductive perform
ance of C. capitata and parasitisation rate, development and reproduct
ion of C. occidentalis. Oviposition, actual fecundity and hatching rat
es of C. capitata were not significantly influenced by metal contamina
tion. The parasitoid did not discriminate between metal-contaminated a
nd control fruit fly pupae. Parasitisation rates were similar in all t
reatments (64.6-65%). Heavy metal induced stress of the host altered n
either the parasitoid developmental rate nor the proportion of females
in parasitoids that emerged from contaminated pupae. Life span and re
productive performance of C. occidentalis females that emerged from me
tal-stressed hosts were not significantly different from control femal
es. However, a significantly lower percentage of females emerged from
copper-and cadmium-contaminated hosts. In groups contaminated by 400 m
u g Cu, 50 mu g Cd and 400 mu g Pb/g diet dw, whole body concentration
s of the respective metals were determined in pupae and imagines of C.
capitata and imagines of C. occidentalis.