Nalikkaramal, Sukritha
- Department of Plant Protection Biology, Swedish University of Agricultural Sciences
Abstract
Mosquitoes rely on diverse internal and external cues to regulate key physiological processes and behaviour. Climate change alters the distribution and behaviour of mosquitoes, including Aedes aegypti, a primary vector of dengue and yellow fever. However, how vectoring females respond to climate change drivers, such as elevation in CO2, and abiotic stressors, including desiccation, remains unclear. This study shows that exposure to elevated CO2 levels combined with extended egg desiccation periods differentially alters larval development and survival, with carry-over effects on adult life-history traits and feeding behaviour (Paper I). Female mosquitoes use their peripheral olfactory system to locate nectar and blood resources. Transcriptomic and functional ontology analyses of olfactory tissues, the antennae and maxillary palp, reveal significant changes in gene expression related to stress and chemosensation, particularly in the CO2-sensing maxillary palp, in response to elevated CO2 and extended egg quiescence (Paper II). Collectively, these findings show that climate change can impact mosquito population dynamics and adult foraging behaviours. Teneral females are attracted to floral sources to replenish their energy reserves, while ageing induces a gradual shift to host-seeking, correlated with a concerted increase in chemosensory receptor expression, with exceptions, such as odorant receptor, Or117 which follows an inverse expression pattern. The mechanism underlying Or117 gene expression and age-dependent floral-seeking was investigated through behavioural assays, electrophysiology, receptor characterisation and functional genomics. Females display an age- and mating-state-dependent floral seeking behaviour, in which Or117 and its ligand, camphor are required for the attraction in teneral unmated females (Paper III). As a whole, the findings broaden our understanding of mosquito adaptation to internal cues and environmental stressors, with implications for vector ecology and disease transmission.
Keywords
Carbon dioxide; Egg quiescence; Climate change; Aedes aegypti; Life-history; Olfactory system; Transcriptome; Floral-seeking; Internal state; CRISPR-Cas9
Published in
Acta Universitatis Agriculturae Sueciae
2025, number: 2025:45
Publisher: Swedish University of Agricultural Sciences
SLU Authors
UKÄ Subject classification
Behavioral Sciences Biology
Zoology
Molecular Biology
Publication identifier
- DOI: https://doi.org/10.54612/a.29djgcqihk
- ISBN: 978-91-8046-480-2
- eISBN: 978-91-8046-530-4
Permanent link to this page (URI)
https://res.slu.se/id/publ/132985