A NOVEL HIGH-THROUGHPUT SCREENING SYSTEM TO EVALUATE THE BEHAVIORAL RESPONSE OF ADULT MOSQUITOES TO CHEMICALS¹

Abstract

A modular and novel assay system for rapid mass screening of chemical compounds for contact irritant and spatial repellent actions against adult mosquitoes is described. The responses of Aedes aegypti to various concentrations of 3 topical repellents, deet, Bayrepel, and SS220, were evaluated. At treatment concentrations > or = 25 nmol/cm2 of SS220, mosquitoes exhibited significant contact irritant (escape) and spatial repellent (movement away from the chemical source) responses, whereas, a 10-fold increase in the treatment concentration of deet and Bayrepel was required to produce similar responses. The novel bioassay system detected contact irritancy and spatial repellency activity with reproducible results and provided baseline data for determining minimum effective concentrations for other chemicals. The system is compact in size, easy to decontaminate, and requires only a minute quantity of chemical compound.

Olfaction in vector-host interactions

“…Each method has its advantages and disadvantages (e.g. Barnard et al 2007, Chareonviriyaphap et al 2002, Dogan and Rossignol 1999, Grieco et al 2005, Hao et al 2008, Klun et al 2005, Rutledge and Gupta 2004. Which bioassay should be used may depend on the research question and possible future application method and may depend on the mode of action of the repellent.…”

“…The most commonly used methods to test putative repellents for employment directly on the human skin have recently been reviewed by Barnard et al (2007). Various types of olfactometers have been used to test compounds for their efficacy as spatial repellents (Bernier et al 2005, Dogan and Rossignol 1999, Grieco et al 2005, Waka et al 2006.…”

Behavioral Responses of Mosquitoes to Insecticides

“…Several years on, a more field-friendly test system was designed that was both collapsible and easily transportable (Chareonviriyaphap & Aum-Aong, 2000;Chareonviriyaphap et al, 2002) and was used to investigate the behavioral responses of various mosquito species and geographical populations from Thailand and a few populations from elsewhere in Asia Sungvornyothin et al, 2001;Kongmee et al, 2004;Pothikasikorn et al, 2005). Recently, a novel modular assay system was developed for mass screening of chemical actions; including contact irritancy, spatial repellency, or toxicity responses, on adult mosquitoes (Grieco et al, 2005). This modular system is substantially reduced in size compared to the previous excito-repellency box and minimizes the treated surface area and therefore the amount of chemical required for testing.…”

“…Moreover, a current ERB design is not conducive for mass screening the candidate chemical compounds. With the development of the HITSS assay (Grieco et al, 2005), a smaller amount of chemical and a lower number of mosquitoes is required per test. In addition, the HITSS can also be configured to test each of the three actions of insecticide compounds, namely contact irritancy assay (CIA) (Fig.…”

“…The HITSS has been standardized and used to evaluate the 3 behavioral responses of Ae. aegypti against DEET, Bayrepel ® , and SS220 (Grieco et al, 2005(Grieco et al, , 2007. Recently, HITSS has been used to define the behavioral responses among six field populations of Ae.…”