Tehran University of Medical Sciences Journal of Arthropod-Borne Diseases 2322-1984 19 4 2026 02 15 1902 1902 Hamid Kassiri School of Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran, Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Morteza Zamanizadeh School of Health, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran, Infectious and Tropical Diseases Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Shahyad Azari-Hamidian 3Research Center of Health and Environment, School of Health, Guilan University of Medical Sciences, Rasht, Iran; Department of Medical Parasitology, Mycology and Entomology, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran 2025 12 23 2026 02 09 Background: Mosquitoes (Diptera: Culicidae), with their blood-sucking behavior, are known important vectors of certain pathogens. Since no research has been done on the habitat characteristics of mosquito larvae in Andimeshk County of Khuzistan Province, southwestern Iran, this study aimed to determine these features in the county during 2019–2020. Methods: The third- and fourth-instar larvae were collected from natural and artificial habitats by the dipping method, from nine localities. Physical characteristics of larval habitats, including habitat situation (permanent/temporary, run­ning/stagnant), sunlight situation, vegetation status, water turbidity, substrate type and habitat type (natural/artificial), were recorded. The collected specimens were kept in vials containing lactophenol and the microscope slides were prepared using Berlese’s fluid. The larvae were identified using valid identification keys. Results: In total, 1363 larvae, including four genera and 15 species, were identified. Eleven species were new to the county and one species, Cx. bitaeniorhynchus, was new to the province. The most common species were Culex theileri (17.2%) and Cx. quinquefasciatus (15.6 %), respectively, and the least species were Anopheles dthali (0.7%) and An.  multicolor (0.4%). The most abundant mosquito larvae were in spring (44.2 %) and June (22.6%). Most of the larvae were caught from natural (75.6%), temporary (51.5%), without vegetation (57.5%) and full sunny (64.7%) habitats. Approxi­mately, 85.2%, 56.5% and 78.1% of habitats had clear water, stagnant water with mud substrate, respectively. The affinity index of the species was calculated.  Conclusion: Regarding the medical importance of the abundant species, the investigation of adult ecology is suggested for future studies. https://jad.tums.ac.ir/index.php/jad/article/view/1902 https://jad.tums.ac.ir/index.php/jad/article/download/1902/710