Liu J. auteur aut IRD Fernandez Diana auteur aut IRD Gao Y. J. auteur aut IRD Silvie Pierre auteur aut IRD Gao Y. D. auteur aut IRD Dai G. H. auteur aut IRD text journalArticle eng text/pdf reformatted digital access Our previous article demonstrated that ar-turmerone ((6S)-2-methyl-6-(4-methylphenyl)-2-hepten-4-one) extracted from Curcuma longa L. has a significant larvicidal activity against the fourth instar larvae ofCulex pipiens pallens. To reveal the effects of ar-turmerone on C. pipiens pallens larvae, light microscopy and transmission electron microscopy were used to observe the histological and ultrastructure changes in muscle and digestive tissues of fourth instar larvae. It was also revealed by detecting the activity of the acetylcholinesterase (AChE) enzyme and three detoxifying enzymes, including carboxylesterase (CarE), glutathione-S-transferase (GST) and Cytochrome P450 monooxidases (P450). The observation under the light microscope showed that the larvae displayed a disruption of myofibril in ventral muscle cells, the disappearance of nucleolus in the malpighian tubule cells, and the exfoliation of the brush border in midgut epithelial cells, 24 h after treatment. The observation under the transmission electron microscope displayed disorganized Z-lines in the ventral muscle cells, and dissolved membrane of mitochondria, nuclear and endoplasmic reticulum in abdominal cells. The enzymatic activity results showed that ar-turmerone significantly increased the level of detoxifying enzymes, while the activity of AChE was not obviously affected. All the results suggest that the larvicidal mechanism of ar-turmerone is estimated to be stomach poison and the active sites might be the muscle and digestive tissues, and the mode of action of ar-turmerone may be unrelated to AChE. specialized phytochemical mosquito immature stages mechanism 076 020 052 11 6 art. 336 [13 p.] 2020 https://www.documentation.ird.fr/hor/fdi:010079366 10.3390/insects11060336 [F B010079366] https://www.documentation.ird.fr/hor/fdi:010079366 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers20-08/010079366.pdf IRD - Base Horizon / Pleins textes 2020-09-17 2020-09-17 fdi:010079366 fre