Morphological and molecular studies on the mosquito (Diptera: Culicidae) species breeding in brackish water habitats of North Kerala

Abstract

Mosquitoes live in almost every conceivable environment where water occurs because the existence of water is a necessity for their larval development.Fresh, brackish, and saline waters are respectively defined as containing <0.5,0.5-30 and >30 ppt (Ramaswamy, 2014). Mosquito larvae are mostly restricted to freshwater environments. Still, all 3 major genera of medical importance (Aedes, Anopheles and Culex) include both freshwater and saltwater species (Coluzzi and Sabatini 1969, Bradley 1987, Jude et;2012). In Kerala, there are nearly 30 brackish water perennial/temporary estuaries, roughly parallel to the Arabian Sea, covering an area of 2, 42,600 ha. The impact of rising Sea levels on coastal ecosystems can indeed exacerbate health risks by altering the habitats of disease vectors. Understanding and mitigating these environmental changes are crucial for preventing the spread of mosquito-borne diseases in vulnerable regions (Surendran, 2011, Ramaswamy, 2012). Moreover, Kerala not only holds a high biodiversity of mosquitoes but has nearly half of its population living and working in coastal areas and maintaining close contact with the sea, creating a conducive situation for epidemiological processes. An ecotype represents specialized groups within a species, adapted to specific local environments through genetic variations. Mosquito larvae were collected from coastal areas of 4 districts (Kasargod, Kannur, Kozhikode and Malappuram) during the period of 4 years (January 2018 to March 2022). The identified species were Anopheles subpictus species complex, An. stephensi, An. barbirostris, Aedes albopictus, Culex sitiens, Cx. quinquefasciatus, Cx. tritaeniorhynchus, Cx. bitaeniorhynchus, Cx. gelidus and Cx. vishnui. An. subpictus species complex was resolved as An. subpictus B and An. subpictus A.