Blend of oviposition-attracting larval holding water compounds as control strategy for Aedes aegypti (Diptera: Culicidae)

GONZALEZ, PAULA V.; HARBURGUER, LAURA V; MASUH, HÉCTOR M

Valparaiso

Congreso; 5th Congress of the Latin American Association of Chemical Ecology (ALAEQ); 2018

ALAEQ

Aedes aegypti (L.) is the vector of dengue, chikungunya, Zika and yellow fever. Chemical factors involved in the selection of the oviposition site by mosquitoes have become a focus of interest in recent years, and considerable attention has been paid to the chemical signals that influence this process. Previous work of our laboratory evaluated the conspecific competition in this species, observing a highstimulation of oviposition in containers containing larvae compared to those without them. With the objective of analyzing the olfactory signals, which may modify the oviposition behavior of Ae. aegypti in presence of larvae, a qualitative analysis of the compounds present in the water which previously contained larvae was carried out using a liquid-liquid extraction technique and subsequent GS-MS analysis. Then, oviposition behavior of different binary blends of larval holding water compounds, including dodecanoic acid, in combination with the n-heneicosane (an oviposition pheromone of Aedes aegypti) were evaluated. The binary combinations tested were (pheromone: acid), 1: 1, 1:10 and 1: 100. Voile cages were used with a binary choice test and 15 gravid females were allowed to choose between a control substrate (solvent) and a treated substrate (blend). The responses were analyzed through the oviposition activity index (OAI) = (Nt-Nc) / (Nt + Nc), where Nt is the average number of eggs placed in the treated water and Nc the average number of eggs placed in the control of water. Fifteen different compounds: dodecanoic acid, tetradecanoic acid, hexadecanoic acid, and various long chain hydrocarbons (C20-C30) were identified from the larval holding water. According to our results, higher OAI values for the 1:10 and 1: 1 combination were obtained compared to the individual components. New blends of oviposition attractants can be used as part of integrated vector management through their application into lethal ovitraps attracting the females to oviposit in these ovitramps inhibiting the emergence of new generations.