Responses of female <i>Aedes aegypti</i> (Diptera: Culicidae) to host odours and convection currents using an olfactometer bioassay

Eiras, Álvaro Eduardo; Jepson, P. C.

doi:10.1017/s0007485300039705

Cited by 72 publications

(42 citation statements)

References 12 publications

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“…To our knowledge, this is the first example of an instantaneous behavioural sensitization of the olfactory circuitry. It differs from classic synergistic responses (Acree et al, 1968;Eiras and Jepson, 1994;Geier and Boeckh, 1999) in that the stimuli are separated in time. Because we analyzed flight tracks upwind of the CO 2 source, our results demonstrate that the increased response to diluted skin odour is caused by true sensitization, i.e.…”

Section: Sensitizationmentioning

confidence: 95%

Carbon dioxide instantly sensitizes female yellow fever mosquitoes to human skin odours

Dekker

Geier

Cardé

2005

Journal of Experimental Biology

238

217

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SUMMARY Female mosquitoes are noted for their ability to use odours to locate a host for a blood meal. Two sensory organs contribute to their sense of smell:the maxillary palps, which measure the level of CO2, and the antennae, which detect other host-released odours. To establish the relative importance and interactions of CO2 and other body emissions in freely flying mosquitoes, we presented female yellow fever mosquitoes Aedes aegypti L. with broad plumes of human skin odour and CO2 at natural concentrations and dilutions thereof in a wind tunnel. 3-D video-recorded flight tracks were reconstructed. Activation,flight velocity, upwind turning and source finding waned quickly as skin odours were diluted, whereas in the presence of CO2 these parameters remained unchanged over more than a 100-fold dilution from exhaled concentrations. Although mosquitoes were behaviourally less sensitive to skin odours than to CO2, their sensitivity to skin odours increased transiently by at least fivefold immediately following a brief encounter with a filament of CO2. This sensitization was reflected in flight velocity, track angle, turning rate upon entering and exiting the broad odour plume and, ultimately, in the source-finding rate. In Ae. aegypti,CO2 thus functions as a `releaser' for a higher sensitivity and responsiveness to skin odours. The initially low responsiveness of mosquitoes to skin odours, their high sensitivity to CO2, and the sensitization of the olfactory circuitry by CO2 are ecologically relevant, because rapidly fluctuating CO2 levels reliably signal a potential host. Possible mechanisms of the instantaneous sensitization are considered.

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Section: Sensitizationmentioning

confidence: 95%

Carbon dioxide instantly sensitizes female yellow fever mosquitoes to human skin odours

Dekker

Geier

Cardé

2005

Journal of Experimental Biology

238

217

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“…Mosquitoes are thought to detect suitable hosts by the presence of a sparse CO 2 plume, which they track by surging upwind and casting crosswind [11]. Upon approach, local cues such as heat and skin volatiles help them identify a landing site [12–15]. Recent evidence suggests that thermal attraction is gated by the presence of CO 2 [6], although this conclusion was based experiments in which the actual flight trajectories of the animals were unknown and visual cues were not studied.…”

mentioning

confidence: 99%

Mosquitoes Use Vision to Associate Odor Plumes with Thermal Targets

et al. 2015

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Summary All moving animals, including flies [1–3], sharks [4], and humans [5], experience a dynamic sensory landscape that is a function of both their trajectory through space and the distribution of stimuli in the environment. This is particularly apparent for mosquitoes, which use a combination of olfactory, visual, and thermal cues to locate hosts [6–10]. Mosquitoes are thought to detect suitable hosts by the presence of a sparse CO2 plume, which they track by surging upwind and casting crosswind [11]. Upon approach, local cues such as heat and skin volatiles help them identify a landing site [12–15]. Recent evidence suggests that thermal attraction is gated by the presence of CO2 [6], although this conclusion was based experiments in which the actual flight trajectories of the animals were unknown and visual cues were not studied. Using a 3-dimensional tracking system we show that rather than gating heat sensing, the detection of CO2 actually activates a strong attraction to visual features. This visual reflex guides the mosquitoes to potential hosts where they are close enough to detect thermal cues. By experimentally decoupling the olfactory, visual, and thermal cues, we show that the motor reactions to these stimuli are independently controlled. Given that humans become visible to mosquitoes at a distance of 5–15 m [16], visual cues play a critical intermediate role in host localization by coupling long-range plume tracking to behaviors that require short-range cues. Rather than direct neural coupling, the separate sensory-motor reflexes are linked as a result of the interaction between the animal’s reactions and the spatial structure of the stimuli in the environment.

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“…Furthermore, application of CO 2 in the field is costly; it needs to be transported into the field in pressurized gas cylinders or as dry ice (Bernier et al, 2003;Curtis, 1996;Knols et al, 1994;Knols et al, 1998;Mboera et al, 2000). By contrast, the use of human-associated kairomones is considered as a good alternative method for collecting, monitoring or controlling host-seeking mosquitoes, as these in a series of behavioral tests in the laboratory and field have shown to elicit high levels of attraction without the presence of CO 2 (Bernier et al, 2003;Edman, 1979;Eiras and Jepson, 1991;Eiras and Jepson, 1994;Gillies and Wilkes, 1974;Silva et al, 2005). The use of GC-SSRs and other analytical methods will be valuable for selecting additional kairomone compounds to optimize an attractive bait.…”

Section: Discussionmentioning

confidence: 99%

Natural odor ligands for olfactory receptor neurons of the female mosquito Aedes aegypti: use of gas chromatography-linked single sensillum recordings

Ghaninia

Larsson²,

Hansson

et al. 2008

Journal of Experimental Biology

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SUMMARYFemale Aedes aegypti are vectors of dengue and yellow fever. Odor volatiles are the predominant cues that drive the host-seeking behavior of Ae. aegypti. Odorant molecules are detected and discriminated by olfactory receptor neurons (ORNs) housed in sensory hairs, sensilla, located on the antennae and maxillary palps. In a previous study, we used odor volatiles that are behaviorally and/or electrophysiologically active for Ae. aegypti and other mosquito species to show that antennal ORNs of female Ae. aegypti are divided into functionally different classes. In the present study, we have, for the first time, conducted gas chromatography-coupled single sensillum recordings (GC-SSR) from antennal trichoid and intermediate sensilla of female Ae. aegypti in order to screen for additional putative host attractants and repellents. We used headspace collections from biologically relevant sources, such as different human body parts (including feet, trunk regions and armpit), as well as a plant species used as a mosquito repellent, Nepeta faassenii. We found that a number of ORN types strongly responded to one or more of the biological extracts. GC-SSR recordings revealed several active components, which were subsequently identified through GClinked mass spectrometry (GC-MS). Electrophysiologically active volatiles from human skin included heptanal, octanal, nonanal and decanal.

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Responses of female Aedes aegypti (Diptera: Culicidae) to host odours and convection currents using an olfactometer bioassay

Cited by 72 publications

References 12 publications

Carbon dioxide instantly sensitizes female yellow fever mosquitoes to human skin odours

Carbon dioxide instantly sensitizes female yellow fever mosquitoes to human skin odours

Mosquitoes Use Vision to Associate Odor Plumes with Thermal Targets

Natural odor ligands for olfactory receptor neurons of the female mosquito Aedes aegypti: use of gas chromatography-linked single sensillum recordings

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