Fauna de culicoides (diptera: ceratopogonidae) do Estado de Rondônia, Brasil

Abstract

The Ceratopogonidae family possesses four hematophagics genus: Forcipomyia, Leptoconops, Austroconops and Culicoides. The Culicoides are insects with 3mm in length, the female are vectors of helminths, protozoan and virus. The main arboviruses transmitted are Oropouche virus, endemic of amazon basin and Bluetongue Virus, which affects both wildlife and domestic livestocks. The convenience collections were done on Alvorada do Oeste, Buritis, Cacoal, Costa Marques, Espigão do Oeste, Guajará-Mirim, Pimenta Bueno, São Francisco Guaporé and Porto Velho municipalities, in Rondônia state through HP light traps between 18:00 and 06:00. Systematic collections were made in Porto Velho municipality on forest and pasture environments. Were collected 2,196 Culicoides (1,515 females and 681 males) distributed throughout 43 species and 27 morfotypes. The species most frequent were Culicoides insignis (n=1,594; 72.59%), C. foxi (n=76; 3.46%), C. hildebrandoi (n=53; 2.41%), C. leopoldoi (n=44; 2%), C. ocumarensis (n=34; 1.55%), C. pusillus (n=29; 1.32%) and C. glabrior (n=28; 1.28%). There were 37 news records of species in Rondônia and three for Brazil. The municipalities with greatest richness were Porto Velho (56), Cacoal (26) e Costa Marques (14). The municipalities with lowest richness were Espigão do Oeste (4), Buritis (3) and Alvorada do Oeste (2). Species with greatest distribution were C. foxi and C. leopoldoi. In Porto Velho were collected 1,773 individuals (1,179 female and 594 males), collected 228 individuals and 51 species in forest, and collected 1,545 individuals and 19 species in pasture. The most abundant species were C. insignis (n=1,472; 83%), C. foxi (n=45; 2.5%), C. glabrior (n=25; 1.4%) and C. ocumarensis (n=23; 1.3%). The forest presented most richness (41 species) and pasture presented greatest abundance (1,545 individuals). In Pasture the most abundant species were C. insignis (1,457-94.30%), C. foxi (34-2.20%) and C. ocumarensis (14-0.90%), and Forest the most abundant species were C. glabrior (25-10.96%), C. insignis (15-6.57%) e C. tetrathyris (15-6.57%). Diversity of species and eveness on Forest environment were greatest than Pasture environment. There was significant statistical difference (p=0.02) on species composition per environment. Diagnoses of some individuals of Rondônia were made. The findings of species of Culicoides on Rondônia now contribute to the total of 46 species, representing 36.8% of amazon species. The species C. darlingtonae, C. contubernalis e C. rodriguezi contribute for ampliation of geographic distribution this species and increase of amazon species fauna. The wide distribution of C. foxi and C. leopoldoi suggest that this species are ecletics for ecotypes and blood meal sources (chicken, livestock and human). The high abundance of C. insignis indicates that feeding behavior on mammals can be one of the factors contributing to the high number of individuals on light traps when placed near blood meal sources. Low number of individuals of C. paraensis on rural areas suggests that this specie is little attracted to light traps due to its diurnal or anthropophilic and urban habit that this species has. In Porto Velho, greatest abundance of C. insignis on Pasture can is related to the wet and muddy substrate with decaying organic matter, which favors the development of immature. The greatest diversity in forest can be explained by water bodies, wetlands, undergrowth, fruit peels present in this breeding sites, which makes it conducive to the proliferation and maintenance of Culicoides species. The diagnosis of the main morphotypes shows differences and similarities in relation to species already described, indicating possible new species for the state of Rondônia.