New insights on black flies (Diptera: Simuliidae) from a touristic destination of Hispaniola

Abstract

Black flies (Diptera: Simuliidae) are well known as annoying biting pests and vectors of disease-causing agents to humans and other animals. Despite their relevance, no studies have been conducted on Hispaniola for decades. Our work aimed to determine the species composition, relative abundance, breeding sites, phylogenetic relationships, and biting habits of black flies from an important ecotourism spot in La Vega Province (Dominican Republic). Simulium ochraceum sensu lato Walker, Simulium haematopotum Malloch, and Simulium quadrivittatum Loew were identified by both morphological and molecular analyses. Black flies were abundant in most (92% of the total) of the flowing water courses studied and their relative abundance varied depending on the method of collection and type of water course. Simulium haematopotum was prominent in large rivers whereas the other two black fly species were more abundant in streams and ditches. The immature stages were found primarily attached to emergent/submerged riparian vegetation and decaying leaves. Phylogenetic analyses based on the mitochondrial cytochrome c oxidase subunit I (COI) gene revealed that the specimens of S. ochraceum s.l. are divided into three clades, and those from the Dominican Republic formed a group with members from Venezuela, Ecuador, Peru, and Colombia. The S. quadrivittatum COI sequences in this study formed a distinct clade from previous collections in Belize and Costa Rica, which might suggest that they represent a species complex. The S. haematopotum sequences were similar to those reported in other countries. Simulium quadrivittatum was the predominant anthropophilic species (statistically significant) and preferred to bite the lower parts of the body of humans. A comprehensive illustrated description of adults (females and males), pupae, and larvae of the three simuliid taxa is provided.