An inventory of human night-biting mosquitoes and their bionomics in Sumba, Indonesia

Mosquitoes are important vectors that transmit pathogens to human and other vertebrates. Each mosquito species has specific ecological requirements and bionomic traits that impact human exposure to mosquito bites, and hence disease transmission and vector control. A study of human biting mosquitoes and their bionomic characteristics was conducted in West Sumba and Southwest Sumba Districts, Nusa Tenggara Timur Province, Indonesia from May 2015 to April 2018. Biweekly human landing catches (HLC) of night biting mosquitoes both indoors and outdoors caught a total of 73,507 mosquito specimens (59.7% non-Anopheles, 40.3% Anopheles). A minimum of 22 Culicinae species belonging to four genera (Aedes, Armigeres, Culex, Mansonia), and 13 Anophelinae species were identified. Culex quinquefasciatus was the dominant Culicinae species, Anopheles aconitus was the principal Anopheles species inland, while An. sundaicus was dominant closer to the coast. The overall human biting rate (HBR) was 10.548 bites per person per night (bpn) indoors and 10.551 bpn outdoors. Mosquitoes biting rates were slightly higher indoors for all genera with the exception of Anopheles, where biting rates were slightly higher outdoors. Diurnal and crepuscular Aedes and Armigeres demonstrated declining biting rates throughout the night while Culex and Anopheles biting rates peaked before midnight and then declined. Both anopheline and non-anopheline populations did not have a significant association with temperature (p = 0.3 and 0.88 respectively), or rainfall (p = 0.13 and 0.57 respectively). The point distribution of HBR and seasonal variables did not have a linear correlation. Data demonstrated similar mosquito-human interactions occurring outdoors and indoors and during early parts of the night implying both indoor and outdoor disease transmission potential in the area-pointing to the need for interventions in both spaces. Integrated vector analysis frameworks may enable better surveillance, monitoring and evaluation strategies for multiple diseases. Author summaryThis study outlines the array of mosquitoes that bite humans at night on the island of Sumba, Indonesia, with data on behavioural traits that impact when and where disease transmission may occur. Biweekly human landing catches (HLCs) were performed in four selected houses in 12 clusters (villages) from sunset to sunrise over a three years period (May 2015 to April 2018). The collection and analysis of 73,507 mosquito specimens revealed the presence of various species of Anopheles, Aedes, Culex, Armigeres and Mansonia, that potentially transmit several diseases including malaria, filaria, dengue and other mosquito borne viral diseases. Even though these data represent only night-time collections, this represents a comprehensive geographic description and inventory of species, bionomics and temporal distribution of mosquitoes on the island of Sumba. Data demonstrate that the high diversity of species with associated diversity in behaviours results in mosquito-human contact occurring throughout the night and both indoors and outdoors-relevant to both disease transmission and intervention applicability. Vector specific behaviours are specifically relevant to intervention strategies for specific diseases. The use of molecular methods to determine and validate morphological identification of specimens resulted in the characterization of multiple novel sequences-indicating the presence of undescribed species, members of cryptic species complexes or species without molecular data. Species identification using molecular methods are essential towards determine vector species compositions-especially in areas where data is absent. Though the correlation between temperature, rainfall and HBR was not statistically significant, the presence of mosquito populations throughout the year allow for perennial transmission of mosquito-borne diseases. Overall, these findings represent baseline and novel data for Sumba and may be utilized to develop disease and vector-specific or integrated strategies that mitigate the transmission of mosquito borne diseases in Indonesia.