Taxonomy, ecology and distribution of the mosquitoes (Diptera: Culicidae) of the Dutch Leeward Islands, with a key to the adults and fourth instar larvae BeekJordy G. van der DijkstraKlaas-Douwe B. HoornBerry B. van der BoerlijstSam P. BusscherLoes KokMaud L. BraksMarieta A.H. SchaffnerFrancis DavelaarGerald J. HenryMaria HulshofKoen LeslieTeresa E. SchramaMaarten 2020 <p>Assessing mosquito biodiversity is important for disease surveillance and ecosystem health assessments. Such studies are particularly needed in regions like the Caribbean, which has experienced a series of recent mosquito borne disease outbreaks but received little attention regarding its invertebrate biodiversity. Here, we report on results from a mosquito survey on the Dutch Leeward Islands (Sint Eustatius, Sint Maarten and Saba), carried out in April and October 2018, which is the first integrative survey since those conducted by Van der Kuyp (1947) and Wagenaar Hummelinck (1949). Moreover, we present a novel key for adults and fourth instar larvae of the mosquitoes of the Dutch Leeward Islands. Overall, eleven species were recorded, eight on Sint Maarten, five on Saba and two on Sint Eustatius. Two new potential disease vectors, <i>Culex nigripalpus</i> and <i>Aedes taeniorhynchus</i>, were recorded on Sint Maarten<i>. </i>One previously recorded species, <i>Cx. habilitator, </i>was not retrieved from any of the islands, which is further discussed in the paper. Species indicative of natural forest which previously occurred on all three islands were absent from Sint Eustatius and Sint Maarten but still present on Saba. In contrast, species indicative of human inhabitation, <i>Ae. aegypti</i> and <i>Cx. quinquefasciatus,</i> were highly abundant on Sint Maarten and Sint Eustatius and present in low numbers on Saba. Overall, the results of this study emphasize the importance of biodiversity surveys and indicate that frequent mosquito inventories may contribute to a better understanding of mosquito community composition and distribution of potential vector species.</p>