Proof of concept for a novel insecticide bioassay based on sugar feeding by adult Aedes aegypti (Stegomyia aegypti)

Abstract

Aedes aegypti L. (Stegomyia aegypti) (Diptera: Culicidae) is the principal vector of dengue and yellow fever viruses in tropical and subtropical regions of the world. Disease management is largely based on mosquito control achieved by insecticides applied to interior resting surfaces and through space sprays. Population monitoring to detect insecticide resistance is a significant component of integrated disease management programmes. We developed a bioassay method for assessing insecticide susceptibility based on the feeding activity of mosquitoes on plant sugars. Our prototype sugar-insecticide feeding bioassay system was composed of inexpensive, disposable components, contained minimal volumes of insecticide, and was compact and highly transportable. Individual mosquitoes were assayed in a plastic cup that contained a sucrose-permethrin solution. Trypan blue dye was added to create a visual marker in the mosquito's abdomen for ingested sucrose-permethrin solution. Blue faecal spots provided further evidence of solution ingestion. With the sugar-insecticide feeding bioassay, the permethrin susceptibility of Ae. aegypti females from two field-collected strains was characterized by probit analysis of dosage-response data. The field strains were also tested by forced contact of females with permethrin residues on filter paper. Dosage-response patterns were similar, indicating that the sugar-insecticide feeding bioassay had appropriately characterized the permethrin susceptibility of the two strains.

Toxicity and Physiological Actions of Carbonic Anhydrase Inhibitors to Aedes aegypti and Drosophila melanogaster

“…To see if toxicity could be improved by blocking oxidative metabolism, a dose of 500 ng PBO was topically applied to mosquitoes 4 h prior to feeding with dichlorphenamide, and an increase in toxicity was observed, with an LC 50 = 486 (310–684) ppm, and a synergistic ratio of 2.2. In this same assay, permethrin had an LC 50 of 15 (12–18) ppm, not too dissimilar from the reported value of 5 ppm for the New Orleans reference strain of Aedes aegypti [23]. …”

Pyrethroid insecticides maintain repellent effect on knock-down resistant populations of Aedes aegypti mosquitoes

“…Unexpectedly, we were not able to detect any statistical difference in mortality between NO and PR mosquitoes exposed to any of the pyrethroids, but this is likely because of extremely low mortality even in the susceptible population. Although the NO mosquitoes used in this study are documented to be pyrethroid-susceptible,[ 24 ] it is possible that they are not completely sensitive to the insecticides used here, given that we found kdr mutations in a large proportion of the tested mosquitoes and observed surprisingly low mortality after arm-in-cage testing.…”

“…Susceptible Aedes aegypti eggs were collected in New Orleans, LA in 2008,[ 23 , 24 ] and generation F12-13 mosquitoes (NO mosquitoes) were used in tests. Resistant Ae .…”

Aedes aegypti Larvicidal Sesquiterpene Alkaloids from Maytenus oblongata

“…Sixty 3–5-day adult females of A. aegypti Paea strain were selected for this test. The ingestion bioassay consisted of impregnating a cotton disk with 2 mL of the insecticide solution, prepared with sucrose (10% v/v) and trypan blue (0.02% v/v). Trypan blue was used to control the ingestion of the product by the mosquitoes.…”