Computational and experimental insights into the chemosensory navigation ofAedes aegyptimosquito larvae

Abstract

Mosquitoes are prolific disease vectors that affect public health around the world. Although many studies have investigated search strategies used by host-seeking adult mosquitoes, little is known about larval search behavior. Larval behavior affects adult body size and fecundity, and thus the capacity of individual mosquitoes to find hosts and transmit disease. Understanding vector survival at all life stages is crucial for improving disease control. In this study we use experimental and computational methods to investigate the chemical ecology and search behavior of Aedes aegypti mosquito larvae. We show that larvae do not respond to several olfactory cues used by adult Ae. aegypti to assess larval habitat quality, but perceive microbial RNA as a potent foraging attractant. Second, we demonstrate that Ae. aegypti larvae use a strategy consistent with chemokinesis, rather than chemotaxis, to navigate chemical gradients. Using computational modeling, we further show that chemokinesis is more efficient than chemotaxis for avoiding repellents in ecologically relevant larval habitat sizes. Finally, we use experimental observations and computational analyses to demonstrate that larvae respond to starvation pressure by optimizing exploration behavior. Our results identify key characteristics of foraging behavior in a disease vector mosquito, including the identification of a surprising foraging attractant and an unusual behavioral mechanism for chemosensory preference. In addition to implications for better understanding and control of disease vectors, this work establishes mosquito larvae as a tractable model for chemosensory behavior and navigation.as the evolutionary adaptations for these systems in 43 synanthropic environments. 44In this work, we investigate larval Ae. aegypti be-45 havior from a chemical ecological and search theory 46 perspective. First, we explore the chemosensory cues 47 involved in larval foraging. Although many olfactory 48 cues are used by adult females to select oviposition 49 sites [18], it is unclear if larvae and adults use the same 50 chemicals to assess larval habitat quality. Second, we 51 consider larval search behavior in spatially restricted 52 environments using empirical data and computational 53 modeling. Our work identifies the functional loss of 54 chemotaxis in foraging larvae -a fascinating example 55 of how environmental restrictions can drive the evo-56 lution of animal behavior. We further identify micro-57 bial RNA as a potent and unusual larval foraging at-58 tractant.Together, our results identify Ae. aegypti lar-59 vae as an exciting outlier in biological search theory, 60 and highlights the importance of investigating synan-61 thropic disease vectors at all life history stages. 62 Results 63 Effects of sex, physiological state, and circadian timing 64 on larval physiology 65 Behavioral experiments in insects have demonstrated 66 the importance of circadian timing, starvation, and age 67 [19]. However, little is known about the effects of these 68 variables on Ae. ae...

Geosmin Attracts Aedes aegypti Mosquitoes to Oviposition Sites

“…In summary, geosmin mediates oviposition site selection in Ae. aegypti and olfactory-guided positive chemokinesis [15] in larvae.…”

“…(D) Non-responsive AL glomeruli (gray) and the geosmin-responsive glomerulus (green; the third posterodorsal glomerulus [PD3]) tentatively registered and mapped to an AL atlas and cross-referenced to a previously published atlas[19]. (E) Glomerular responses (DF/F 0 ) to geosmin characterized at five depths(15,30, 50, 75, and 90 mm) from the ventral surface of the AL. Each trace is the mean of one glomerulus; the PD3 response is shown in green.…”

Computational and experimental insights into the chemosensory navigation of Aedes aegyptimosquito larvae

“…Code associated with this manuscript can be found at: . Data available from the Dryad Digital Repository: [46].…”