Flight activity of insecticide resistant and susceptible Anopheles stephensi mosquitoes in actograph chambers lined with malathion, γ HCH or dieldrin

Abstract

The activity and resting behaviour of resistant and susceptible Anopheles stephensi Liston were recorded in acoustic actograph chambers lined with residual deposits of malathion, dieldrin or gamma HCH. In gamma HCH-treated flight chambers, SS and RS mosquitoes became active only after picking up lethal doses of insecticide, which explains why few SS and RS mosquitoes survive release into gamma HCH-treated experimental huts. Similar results were obtained in flight chambers treated with dieldrin; however, more mosquitoes would be expected to survive dieldrin under field conditions because resistance to this insecticide is greater than to gamma HCH. Mosquitoes in contact with malathion showed a three-phase activity pattern: an initial active phase, an inactive phase, and hyper-activity/convulsions. Initial activity or irritability was especially pronounced in SS and RS but absent in RR mosquitoes. Whether or not irritability would protect RS mosquitoes from malathion would probably depend on the ratio of sprayed to unsprayed surfaces in treated huts.

Spatial Heterogeneity and Insect Adaptation to Toxins

“…Strain comparisons, however, are of limited value in understanding the interaction between behavioral response and physiological tolerance because selection does not act upon strains, and the differences among strains could result from different selection intensities on behavior and physiology rather than from genetic relationships between them. Consistent with previous reviews (108,125,147), recent results describing differences between strains characterized as resistant and susceptible have provided examples where susceptible strains are more behaviorally responsive (6, 87,103,114,132,133,151,170), less behaviorally responsive (109,151,164,170), and equally responsive (140) when compared with resistant strains. Overall, some correlation between behavior and physiology, whether positive or negative, appears to be the rule.…”

The Importance of Mosquito Behavioural Adaptations to Malaria Control in Africa

“…A side effect of physiological resistance is often a reduction in the behavioral responsiveness to the insecticide (Rowland 1990; Hodjati and Curtis 1997). For example, in one study, pyrethroid resistant mosquitoes show reduced irritability when in contact with the insecticide causing them to rest on the surface for longer periods than susceptible mosquitoes, thus increasing the dose of insecticide received (Hodjati and Curtis 1997).…”

Resting Behaviour of Deltamethrin-Resistant Malaria Vectors, Anopheles arabiensis and Anopheles coluzzii, from North Cameroon: Upshots from a Two-Level Ordinary Logit Model

“…When the LLIN is intact, a side effect of physiological resistance would be the reduction in vector behavioural responsiveness to the insecticide [44][45][46]. Pyrethroid-resistant mosquitoes showed reduced irritability to insecticides, which allow them to rest on the surface for longer periods than susceptible mosquitoes, thus increasing the dose of insecticide received and likely the subsequent mortality rates [46].…”