title: Enantiomeric selectivity in behavioural and electrophysiological responses of Aedes aegypti and Culex quinquefasciatus mosquitoes.
abstract: 1-Octen-3-ol is a kairomone for many haematophagous insects including mosquitoes. Numerous studies have examined the effects of racemic 1-octen-3-ol; however, few studies have investigated the role of individual enantiomers in relation to mosquito attraction. In the present study, we investigated the behavioural and electrophysiological responses of two mosquito species, Aedes aegypti and Culex quinquefasciatus, to individual enantiomers and mixtures of 1-octen-3-ol, employing a laboratory Y-tube olfactometer and single sensillum recordings. The olfactory receptor neurons of both Ae. aegypti and Cx. quinquefasciatus had a significantly higher response to the (R)-1-octen-3-ol enantiomer compared to the (S)-1-octen-3-ol enantiomer at 10-9 g μl-1 to 10-6 g μl-1. Behaviourally, Ae. aegypti was more responsive to the (R)-1-octen-3-ol enantiomer, showing an increase in flight activity and relative attraction compared to Cx. quinquefasciatus. The (R)-1-octen-3-ol enantiomer caused an increase in activation for Cx. quinquefasciatus. However, the most notable effect was from an (R:S)-1-octen-3-ol mixture (84:16) that caused significantly more mosquitoes to sustain their flight and reach the capture chambers (demonstrated by a reduced non-sustained flight activity), suggesting that it may have a behaviourally excitatory effect. For Cx. quinquefasciatus, a reduced relative attraction response was also observed for all treatments containing the (R)-1-octen-3-ol enantiomer, either on its own or as part of a mixture, but not with the (S)-1-octen-3-ol enantiomer. This is the first time enantiomeric selectivity has been shown for Ae. aegypti using electrophysiology in vivo. The implications of these results for exploitation in mosquito traps are discussed.
authors: Centre for Sustainable Pest and Disease Management, Chemical Ecology Group, Biological Chemistry Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK.
authors: J I
authors: JI
authors: Cook
authors: S
authors: S
authors: Majeed
authors: R
authors: R
authors: Ignell
authors: J A
authors: JA
authors: Pickett
authors: M A
authors: MA
authors: Birkett
authors: J G
authors: JG
authors: Logan
mesh_terms: D000330:Aedes / Q000187:drug effects*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D003465:Culex / Q000187:drug effects*; D005260:Female; D005426:Flight, Animal / Q000187:drug effects; D000442:Octanols / Q000737:chemistry / Q000494:pharmacology*; D018034:Olfactory Receptor Neurons / Q000187:drug effects; D010675:Pheromones / Q000737:chemistry / Q000494:pharmacology*; D058618:Sensilla / Q000187:drug effects*; D013237:Stereoisomerism
chemical_list: D000442:Octanols; D010675:Pheromones; C010411:insect attractants; C038844:1-octen-3-ol