{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,4]],"date-time":"2026-09-04T00:13:44Z","timestamp":1788480824329,"version":"build-2803163510"},"reference-count":51,"publisher":"Oxford University Press (OUP)","license":[{"start":{"date-parts":[[2026,8,12]],"date-time":"2026-08-12T00:00:00Z","timestamp":1786492800000},"content-version":"am","delay-in-days":1,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"funder":[{"name":"Centre for Global Change at the University of the Free State\u2014QwaQwa Campus, South Africa"},{"DOI":"10.13039\/501100001321","name":"National Research Foundation","doi-asserted-by":"publisher","award":["128386"],"award-info":[{"award-number":["128386"]}],"id":[{"id":"10.13039\/501100001321","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Geotaxis is the behavior of an organism in response to gravitational forces. Mosquito larvae display innate negative geotaxis in water. This study explored how exposure to pymetrozine (PYM) and manganese (Mn) affects the geotaxis of Culex sp. larvae in water, and whether this behavior could be a useful endpoint in aquatic ecotoxicology. Culex sp. larvae were exposed to varying concentrations of both chemicals, and their geotaxis was monitored for 10 min. Additionally, 24-hr mortality bioassays were carried out to obtain novel data on the lethal effects of both chemicals on Culex sp. larvae. Mortality experiments revealed that PYM caused significant larval mortality with an median lethal concentration (LC50)\u00a0of 60.75 (54.29\u201367.98) mg\/L. Manganese showed a moderate lethal effect with an undetermined LC50 value due to insufficient mortality across the tested concentration range (i.e., 0\u2013345.50\u2009mg Mn\/L). Geotaxis testing revealed that in the control, the mosquito larvae spent, on average, 78.23% of their time in negative geotaxis. Exposure to Mn significantly decreased this innate rate to 62.71% in the 172.75\u2009mg Mn\/L treatment (p\u2009&amp;lt;\u20090.05), whereas exposure to PYM lowered it further to 54.54% in the 8.25\u2009mg PYM\/L treatment (p\u2009&amp;lt;\u20090.05). These significant reductions in negative geotaxis in contaminated water samples suggest that geotaxis could serve as a useful endpoint for the quick assessment of water pollution. However, because the geotaxis dose\u2013response curves were biphasic, validation using other aquatic life forms may be required, especially at lower concentrations, to ensure that systemic shutdown in the larvae at higher concentrations is not misinterpreted as genuine geotaxis responses.<\/jats:p>","DOI":"10.1093\/etojnl\/vgag221","type":"journal-article","created":{"date-parts":[[2026,8,12]],"date-time":"2026-08-12T05:58:21Z","timestamp":1786514301000},"source":"Crossref","is-referenced-by-count":0,"title":["Altered negative geotaxis in\n                    <i>Culex<\/i>\n                    sp. larvae exposed to pymetrozine and manganese: Implications for behavioral aquatic ecotoxicology"],"prefix":"10.1093","author":[{"given":"Patricks","family":"Voua Otomo","sequence":"first","affiliation":[{"name":"Ecotoxicology Research Laboratory, Department of Zoology and Entomology, Faculty of Natural and Agricultural Sciences, University of the Free State , 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