Mosquitoes utilize highly specialized sensory structures and chemical receptors to detect volatile odors and to orient toward potential host species. Resources that are generally essential to mosquito survival and reproduction include blood for egg development, water for egg laying and immature stages, and nectar for cellular respiration. Currently, a critical gap exists in our understanding of the molecular receptive basis of behavioral responses to volatile compounds like carboxylic acids (CAs), which serve as attractants for host seeking females. The act of blood feeding is a critical link in the transmission of disease-causing pathogens like arboviruses between humans, and between animals to humans. Therefore, it is imperative that we learn more about the mechanisms that are fundamental to mosquito chemical sensing, especially in vector species such as Aedes aegypti and Aedes albopictus. Here we propose to apply a heterologous expression system to characterize the responses of a prioritized subset of candidate CA chemoreceptors that are conserved across mosquito taxa. In parallel, we will apply cutting-edge technologies to generate genetic disruptions of high-priority chemoreceptors, based upon their conservation and their potential to mediate responses to CAs. We will utilize a uniport olfactometer and dual-choice assay paradigms to examine the impacts of CAs on adult female behaviors under various physiological states, comparing wild-type versus gene-disrupted lines. The experiments described in this proposal will help illuminate the roles that CAs play in the biology of Aedes species. By extension, the discoveries made are likely to apply to other insect taxa, including those with medical, veterinary, and agricultural importance. As the efficacy of current control strategies erodes in the wake of insecticide resistance and behavioral adaptations, deepening our understanding of the chemosensory abilities of Ae. aegypti and Ae. albopictus may facilitate future improvements in surveillance technologies and in the development of novel methods for disrupting arbovirus transmission.
Mosquitoes respond to chemical cues in the environment, such as carboxylic acids (CAs), to locate resources for survival and reproduction. The molecular receptors that are responsible for CA detection are not well characterized. This study will improve our understanding of CA detection in Aedes mosquitoes and could lead to improved methods of monitoring and controlling mosquito populations.