Cartography of odor chemicals in the dengue vector mosquito (Aedes aegypti L., Diptera/Culicidae)

Abstract

This study was aimed to identify the chemical compounds of Aedes aegypti that can be potentially used to develop pheromone-based vector control methods. In this study, we compared the chemical compounds collected from the organs of mosquitoes at different developmental stages in the life cycle. We also compared the composition and amount of extracts from the different tissues of male and female adult mosquito. Interestingly, we found large amount of C17-C20 ethyl and methyl esters in the wings of female and antennae of male mosquito. We also found that isopropyl esters, dodelactone, octadecenoic acid and medium-chain fatty acid increase drastically during the late larval stage (L4). Old adult mosquitoes showed remarkable increase in production of C16:1 and C18:1 methyl esters, as a first example of chemical signatures specifically associated with aging in the animals. This knowledge may open the ground to find new behaviorally-important molecules with the ability to control Aedes specifically.

Behavioural and antennal responses of Aedes aegypti (l.) (Diptera: Culicidae) gravid females to chemical cues from conspecific larvae

“…For instance, two carboxylic acids recently identified in larval extracts, dodecanoic acid and tetradecanoic (i.e. myristic) acid [ 27 ], have also been previously found in Ae . aegypti eggs extracts [ 13 ].…”

“…Chemical compounds used for electroantennography (EAG) and oviposition bioassays were previously identified from extracts of immature stages of Ae . aegypti (3 rd and 4 th larval instars and pupae) [ 27 ]. The isovaleric acid, myristoleic acid, myristic acid and pentadecanoic acid synthetic compounds (purity ≥ 99%; Sigma Aldrich Inc., St-Louis, MO, USA) were diluted in n- hexane (HPLC grade; Carlo Erba reagents, Milano, Italy).…”

“…The four synthetic compounds were tested both individually and in blend at 4 concentrations. The blend was obtained by mimicking the proportions observed in larvae extracts as follows: 13% isovaleric acid, 53% myristoleic acid, 23% myristic acid and 11% pentadecanoic acid [ 27 ]. A second mixture of compounds was also prepared by removing myristoleic acid from the blend (respecting the proportions of the three other compounds, i.e.…”

“…More recently, the identification of 15 compounds (including 8 carboxylic acids, 2 corresponding methyl esters, and 1 lactone) in Ae . aegypti larval extracts represents to date the widest diversity of larval compounds identified [ 27 ], and raises questions about their implication in the oviposition behaviour. Most of them are long-chain fatty acids and are therefore expected to present low volatility and act as taste cues rather than at distance.…”

“…The present study gives more insight into the relationship between female oviposition behaviour and the chemical signature linked to the presence of immature conspecifics. Hence, we aimed to ( i ) confirm the impact of larval density on the oviposition site selection, ( ii ) assess the olfactory perception and the influence on oviposition behaviour of the four major compounds identified from larval extracts by Wang and colleagues [ 27 ]: isovaleric acid (C 5 H 10 O 2 ), myristoleic acid (C 14 H 26 O 2 ), myristic (i.e. tetradecanoic) acid (C 14 H 28 O 2 ) and pentadecanoic acid (C 15 H 30 O 2 ), and to ( iii ) evaluate their competitiveness when compared to natural odours of Ae .…”