Semiochemical oviposition cues to control Aedes aegypti gravid females: state of the art and proposed framework for their validation

Abstract

In the fight against mosquito-borne diseases, odour-based lures targeting gravid females represent a promising alternative to conventional tools for both reducing mosquito populations and monitoring pathogen transmission. To be sustainable and effective, they are expected to use semiochemicals that act specifically against the targeted vector species. In control programmes directed against Aedes aegypti, several candidates of different origins (conspecifics, plants) have already been identified as potential oviposition attractants or repellents in laboratory experiments. However, few of these candidates have received validation in field experiments, studies depicting the active molecules and their mode of perception are still scarce, and there are several methodological challenges (i.e. lack of standardization, differences in oviposition index interpretation and use) that should be addressed to ensure a better reproducibility and accelerate the validation of candidates. In this review, we address the state of the art of the compounds identified as potential candidates for trap development against Ae. aegypti and their level of validation. We also offer a critical methodological analysis, highlight remaining gaps and research priorities, and propose a workflow to validate these candidates and to increase the panel of odours available to specifically trap Ae. aegypti. Graphical Abstract

Biology and Behaviour of Aedes aegypti in the Human Environment: Opportunities for Vector Control of Arbovirus Transmission

“…aegypti females preferred to lay eggs in water that currently or previously contained the predatory copepod Mesocyclops longisetus , (possibly in response to copepod-derived terpenes in the water). Studies of this type continue to be published but the promise of the use of semiochemicals as baits for attractant traps or as biting repellents has yet to be realised [ 188 ]. Geosmin, “the smell of earth after rain” is a sesquiterpenoid associated with streptomyces bacteria that mediates oviposition by Aedes aegypti where it is decoded by the olfactory system in a precise manner not dissimilar from that interpreting human host cues [ 189 ].…”

Chikungunya Virus Infection and Gonotrophic Cycle Shape Aedes aegypti Oviposition Behavior and Preferences

“…For the study testing females in groups, ovary dissection was not performed; therefore, the total number of tested females was used to calculate the mean number of eggs laid per female, which can lead to an overestimation of the responding females. Design considerations have been proposed for increasing the reproducibility of oviposition experiments, which could allow for an improvement in the comparison between studies [ 42 , 43 ].…”

Chemical Ecology and Management of Dengue Vectors

“…Finding a suitable site to lay eggs is critical to the survival of an insect species; gravid female mosquitoes lay their eggs in a suitable aquatic site (82,139). Gravid females must navigate chemical cues released from these sites to lay their eggs.…”

“…Physiochemical factors (e.g., container type, color, size, shape, and volume; fill method; temperature; pH; lid type; exposure to sun) have been described in relation to container larval productivity (29,123,139,142). Sources of olfactory cues released from these sites include plant infusions, conspecific and heterospecific larvae, and microorganisms (82), although how these sources interact to define specific site choice is less well understood.…”

“…We focus on the contributions of olfaction to specific behaviors of these two dengue vectors: host seeking for a blood meal from a vertebrate, plant feeding, mating, and oviposition. We discuss other literature detailing the contributions of olfaction that underlie these behaviors (for reviews, see 11,82,140), albeit minimally described in Ae. albopictus; however, we emphasize knowledge gaps related to the underlying genetic mechanisms modulating these behaviors.…”