Aedes aegypti larvae respond to Natural and Synthetic Odorants.

PAULA GONZALEZ; PAOLA GONZALEZ AUDINO; HÉCTOR MASUH

Córdoba, Huerta Grande

Encuentro; 2nd Latin American Meeting of Chemical Ecology; 2012

Facultad de agronomia, universidad de buenos aires,

The ability to detect a wide range of sensory cues is essential for the survival and vectorial capacity of mosquitoes. Of these sensory stimuli, chemosensory inputs, especially olfactory cues, are crucial in food detection, mating, predator avoidance and other behaviors. This investigation focuses on the analysis of olfactory-driven behavior in dengue vector mosquito Aedes aegypti (L.) larvae to respond to synthetic or natural odorant stimuli.Mosquitoes have four distinct developmental stages: egg, larva, pupa and adult. Immature stages of mosquitoes require water to complete their life cycle. The larvae will go through four developmental stages called instars. We established a sensitive olfaction-based behavior assay, following the technique of Xia et al. [1] with minor modifications, that tracks the ability of Ae. aegypti larvae to respond to a range of synthetic and natural odorant stimuli. In this assay, the distribution of 100 2nd or 3nd instar larvae was monitored to a range of odorants stimuli as well as appropriate negative controls throughout a 60 minute time course. The number of larva in both test and control zone was counted throughout all time-point and performance index (PI) at 40min was calculated to represent the response characteristics of each odorant with +1 indicative of full attraction while ?1 represents complete repulsion.We tested various odorants, studying behavioral olfactory response of the larvae exposed. The widely used insect repellent N, N-diethyl-m-toluamide (DEET), consistently evoked highly significant negative PI and when using yeast extract, a know food source, the larvae responded with a significantly positive PI.Little is known about olfactory processes and the relevant behaviors of pre-adult stage dengue vector mosquitoes. It is important to study the behavior of attractant and repellency, as it could contribute to the understanding of the mechanism of olfaction in Ae aegypti larvae. [1] Yuanfeng Xia, Guirong Wang, Daniela Buscariollo, R. Jason Pitts, Heidi Wenger, and Laurence J. Zwiebel. (2008).The molecular and cellular basis of olfactory-driven behavior in Anopheles gambiae larvae. PNAS, 105 (17): 6433- 6438.