Published online by Cambridge University Press: 10 July 2009
The effects on the emerging adult of topical application of 14C-dieldrin to third-instar larvae of Musca domestica L., and the distribution of the insecticide in the fly, the puparial case, and the holding medium, were examined. The dose ranged from 0·04 to ca 13 μg/larva. All flies emerging after treatments of 1 μg and above showed symptoms of poisoning some time after emergence. With the larger doses an increasing number of flies, although they escaped the puparium, were unable to reach the surface of the holding medium. With the two top doses some were unable to escape fully from the puparial case. These flies contained amounts of dieldrin well in excess of the LD99 dose. However, even the highest dose allowed some flies to emerge normally. None of the treatments affected metamorphosis and all flies appeared morphologically normal. The data provided evidence that the transfer of dieldrin to the adult via the pupal stage accounts for the effects in the newly emerged fly.