title: Impact of elevated CO2 background levels on the host-seeking behaviour of Aedes aegypti.
abstract: Mosquitoes rely on carbon dioxide (CO2) to detect and orient towards their blood hosts. However, the variable and rapid fluctuations of atmospheric CO2 concentrations may have an impact on the host-seeking behaviour of mosquitoes. In this study, we analysed the effect of transient elevated background levels of CO2 on the host-seeking behaviour and the physiological characteristics of the CO2-sensitive olfactory receptor neurones (ORNs) in female yellow fever mosquitoes, Aedes aegypti. We show that the take-off and source contact behaviour of A. aegypti is impeded at elevated background levels of CO2 as a result of masking of the stimulus signal. The mechanism underlying this masking during take-off behaviour is one of sensory constraint. We show that the net response of the CO2-ORNs regulates this CO2-related behaviour. Since these neurones themselves are not habituated or fatigued by the transient elevation of background CO2, we propose that habituation of second-order neurones in response to the elevated CO2-ORN activity could be one mechanism by which the net response is transduced by the olfactory system. The findings from this study may help to predict future shifts in mosquito-host interactions and consequently to predict vectorial capacity in the light of climate change.
authors.affiliation: Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, PO Box 102, SE-230 53, Alnarp, Sweden.
authors.forename: Shahid
authors.initials: S
authors.lastname: Majeed
authors.forename: Sharon Rose
authors.initials: SR
authors.lastname: Hill
authors.forename: Rickard
authors.initials: R
authors.lastname: Ignell
mesh_terms: D000330:Aedes / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D002245:Carbon Dioxide / Q000494:pharmacology*; D057231:Climate Change; D005247:Feeding Behavior / Q000187:drug effects
chemical_list: D002245:Carbon Dioxide
keywords: Absolute detector; Climate change; Olfaction; Single sensillum recording; Wind tunnel