Investigation of a permethrin‐induced antifeedant effect in Drosophila melanogaster: An ethological approach

Abstract

A permethrin‐induced antifeedant effect was demonstrated in Drosophila melanogaster topically treated with a dose of 1.25 ng per fly (LD50 and LD10 were 18.5 and 7.4 ng of permethrin per fly, respectively). The reduction in food consumption in treated flies was due to a decrease in the frequency of feeding and not to the duration of individual meals. These results suggested that the sublethal effect occurred before the process of ingestion. Furthermore, a time‐sampling study of individual flies, 30 min after treatment, revealed that the relative frequency of the components of general behaviour were altered. Specifically, locomotory behaviour and inactivity were significantly decreased in contrast to preening, which increased. Continuous observation for 30 min revealed that whilst the length of preening bouts was unaltered, their frequency of occurrence was significantly increased in permethrin‐treated flies. The length of bouts of locomotory activity was significantly reduced in treated individuals, but the frequency was increased. The length of rest periods was reduced in treated flies, but no influence of the insecticide could be detected on their bout frequency. Sequential analysis of the transition frequencies of the behavioural components suggested that an underlying disorganisation of general behaviour resulted from the insecticide treatment. Further analysis, of the behaviour of those flies that had fed, indicated that the probability of tasting leading to feeding was decreased by permethrin. The increase in preening behaviour was thought to cause the reduction in locomotor activity, that ultimately resulted in the reduction in feeding. This is discussed in relation to the physiological basis of pyrethroid action and a subsequent irritation response to low doses.

Comparative Toxicology of the Pyrethroid Insecticides

“…These effects are induced by doses lO-fold lower than lethal levels (Tan 1981). Quantification of the behavioral effects has been achieved by using Drosophila (Armstrong and Bonner 1985). The behavioral toxicity may not only reduce feeding, but make the insects more susceptible to predation, parasitism, and dessication as well.…”

Effects of sublethal doses of beta-cyfluthrin on mutant Drosophila melanogaster (Diptera: Drosophilidae)

“…The advantage of sublethal effects can supplement the lethal effects in many ways as by reducing the reproductive potential, inducing starvation, or causing the insects to avoid treated surfaces. Synthetic pyrethroids have been observed to exert such effects and have been reported to give better control and higher yields than expected from LD 50 values (Armstrong and Bonner, 1985).…”

Effect of Fenvalerate-20EC on Sericigenous Insects

“…The LC treatment even induced rectal protrusion and slow death of weaker larvae. Similar irritation responses were recorded in Drosphila melanogaster on pyrethroid treatment (Armstrong and Bonner, 1985), and in B. mori with various insecticides (Kuribayashi, 1988). The insecticide to some extent may be eliminated by regurgitation and/or excretion as reported by Khan (1993).…”

“…Most insecticides sprayed on phytophagous insects are nerve poisons, which have antifeeding e!ects in#uencing the food intake or food rejection (Gist and Pless 1985;Armstrong and Bonner 1985;Iftner et al, 1986;Nagia et al, 1989). The consumption and utilization of mulberry leaves by the silkworm, Bombyx mori L., forms a major aspect of study in the "eld of sericulture.…”