| Title: | Odour-mediated oviposition site selection in Aedes aegypti depends on aquatic stage and density |
| Author(s): | Khan Z; Bohman B; Ignell R; Hill SR; |
| Address: | "Disease Vector Group, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 190, 234 22, Lomma, Sweden. Disease Vector Group, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 190, 234 22, Lomma, Sweden. sharon.hill@slu.se" |
| DOI: | 10.1186/s13071-023-05867-1 |
| ISSN/ISBN: | 1756-3305 (Electronic) 1756-3305 (Linking) |
| Abstract: | "BACKGROUND: Olfaction plays an important role in the selection and assessment of oviposition sites by mosquitoes. Volatile organic compounds (VOCs) associated with potential breeding sites affect the behaviour of gravid mosquitoes, with VOCs from aquatic stages of conspecific mosquitoes influencing and regulating oviposition. The purpose of this study was to conduct a systematic analysis of the behavioural response of gravid Aedes aegypti to conspecific aquatic stage-conditioned water, to identify the associated bioactive VOCs and to determine how blends of these VOCs regulate oviposition site selection and stimulate egg-laying. METHODS: Using a multi-choice olfactory oviposition assay, controlling for other sensory modalities, the responses of individual females to water conditioned with different densities of conspecific aquatic stages were assessed. The conditioned water samples from the most preferred density of each aquatic stage were subsequently compared to each other using the same oviposition assay and analysed using an analysis of variance (ANOVA) followed by a Tukey post-hoc test. Using combined gas chromatography and electroantennographic detection or mass spectrometry, bioactive VOCs from the preferred density of each aquatic stage were identified. Synthetic blends were prepared based on the identified ratios of bioactive VOCs in the aquatic stages, and then tested to determine the oviposition choice of Ae. aegypti in a dose-dependent manner, against a solvent control, using a dual-choice assay. This dataset was analysed using nominal logistic regression followed by an odds ratio comparison. RESULTS: Gravid Ae. aegypti responded stage- and density-dependently to water conditioned with eggs, second- and fourth-instar larvae, and pupal exuviae, but not to water conditioned with pupae alone. Multi-choice assays demonstrated that gravid mosquitoes preferred to oviposit in water conditioned with fourth-instar larvae, over the other aquatic stage-conditioned water. Gravid Ae. aegypti were attracted, and generally stimulated, to oviposit in a dose-dependent manner to the individual identified synthetic odour blends for the different aquatic stages. CONCLUSIONS: Intraspecific VOCs regulate oviposition site selection in Ae. aegypti in a stage- and density-dependent manner. We discuss the need for further studies to evaluate the identified synthetic blends to modulate the odour-mediated oviposition of Ae. aegypti under field conditions" |
| Keywords: | Animals Female *Aedes/physiology Odorants Oviposition/physiology Smell Larva/physiology Water *Volatile Organic Compounds/pharmacology Immature stages Mosquito behaviour Synthetic odour blends Volatile organic compounds; |
| Notes: | "MedlineKhan, Zaid Bohman, Bjorn Ignell, Rickard Hill, Sharon Rose eng England 2023/08/05 Parasit Vectors. 2023 Aug 4; 16(1):264. doi: 10.1186/s13071-023-05867-1" |
