The impact of insecticide-treated cloth targets on the survival of Stegomyia polynesiensis (= Aedes polynesiensis) under laboratory and semi-field conditions in French Polynesia.

The impact of deltamethrin-impregnated cloth targets on Stegomyia polynesiensis (= Aedes polynesiensis) (Marks) (Diptera: Culicidae) was assessed under laboratory and semi-field settings in French Polynesia. Stegomyia polynesiensis females were released into small laboratory cages and large field cages containing either a deltamethrin-treated or an untreated navy blue cloth, and mosquito knock-down and mortality were assessed. The 24-h mortality rate in mosquitoes exposed to the insecticide-treated target in small cages was 98.0%. These mosquitoes also demonstrated significantly higher levels of knock-down than those exposed to the untreated target. Mortality in field cages was assessed at 24 and 48 h. The 24-h mortality rate in mosquitoes exposed to the control target was 31.2%, whereas that in those exposed to the deltamethrin-treated target was 54.3%. The 48-h mortality rate was also elevated in mosquitoes exposed to the deltamethrin-treated target, but this result did not differ significantly from that observed in mosquitoes exposed to the control target. The significant suppression of female S. polynesiensis by deltamethrin-treated resting targets in this study indicates that these targets could play a role in the control of an important disease vector in the South Pacific region.

First record of Wyeomyia (Wyeomyia) mitchellii (Diptera: Culicidae) in French Polynesia.

Wyeomyia (Wyeomyia) mitchellii (Theobald) was discovered in 2007 and 2008, respectively, in Moorea and Tahiti, two islands of the Society Islands (archipel de la Société) in French Polynesia. A few adult specimens were captured using a CDC backpack aspirator and BG-Sentinel mosquito traps. Wy. mitchellii larvae were found in water-impounding bromeliads and aroids at various survey sites around Tahiti. Imported bromeliads likely played a critical role in the introduction, establishment, and maintenance of Wy. mitchellii in Tahiti and Moorea. Bromeliads and aroids are common in residential areas, thereby increasing the exposure of human and domestic animals to Wy. mitchellii, which is of public health and veterinary concern. The establishment of Wy. mitchellii in French Polynesia requires further study.

Landing response of Aedes (Stegomyia) polynesiensis mosquitoes to coloured targets.

Aedes polynesiensis Marks (Diptera: Culicidae) is the primary vector of lymphatic filariasis (LF) in the island countries and territories of the South Pacific. In the development of a novel control tool, the response of Ae. polynesiensis to six different colours (three solid fabrics, two patterned fabrics and a plastic tarp) was measured using a digital photographic system. Adult mosquitoes were placed into an environmental chamber and allowed to choose between a white target and one of six experimental targets. Mosquito landing frequency and landing duration were calculated. Adult female Ae. polynesiensis preferred all of the experimental targets to the white control target. Mosquito landing frequency was highest for the solid targets (black, navy blue and red) followed in turn by the two colour pattern targets and the polyethylene target. Mosquito landing duration was greater for experimental targets when compared with white control targets. Mosquito landing frequencies did not change over time during the course of the assay. The response of male Ae. polynesiensis was also measured when exposed to a 100% cotton black target. Male mosquitoes preferred the black target to the white control target, although at levels lower than that observed in female mosquitoes. The results suggest that future investigations evaluating the visual responses of Ae. polynesiensis mosquitoes are warranted, with a special emphasis on semi-field and field-based experiments.