3rd Conference on Neglected Vectors and Vector-Borne Diseases (EurNegVec): with MC and WG Meeting of the COST Action TD1303 Mosquito (Diptera: Culicidae) Species Diversity and Distribution in Tartu, Southern Estonia Kirik H.1, Burtin V.1, Tummeleht L.2, Kurina O.1 1 Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia 2 Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Tartu, Estonia Email: hekirik@gmail.com The netting protocol used in this study proved an adequate low cost method for small-scale mosquito surveillance. There were no statistically significant differences between sampling sites. However, species composition of the local mosquito population changed throughout the warm months in accordance with general knowledge. This study will be continued by collecting additional mosquitoes in Tartu, as well as in other areas of Estonia and inspecting the samples for pathogens. Conclusions 1 492 mosquitoes were captured in total. So far, 23 mosquito species have been definitively identified. Based on this data, the most numerous species were Ochlerotatus communis (De Geer, 1776) in 2013 and Ochlerotatus punctor (Kirby, 1837) in 2015. All of the species recorded in 2013 are considered to be relatively common in Estonia. However, DNA analysis of the 2015 material requires further examination before final conclusions can be drawn. It is possible, that there are more mosquito species in Estonia, than previously recorded. Mosquito diversity, calculated using the Shannon-Wiener index, did not vary between the sampling sites, but it did fluctuate significantly over the study period (Kruskal–Wallis ANOVA: H= 42.79, p= 0.0005) (Figure 1). The quantity of captured mosquitoes also changed significantly over time (Kruskal–Wallis ANOVA: H= 46.82, p= 0.0001). By far, mosquitoes were most numerous during the month of May, followed by smaller fluctuations throughout the season. However, the species composition changed during the study period as generally expected (Figure 2). Results Mosquitoes have not been comprehensively studied in Estonia since 1954. There is no data on whether new species have emerged or previously widespread ones withdrawn. An increase in travel and trade has made it easier for pathogens as well as vectors to spread, and insects are known to be particularly sensitive to environmental chances. This preliminary study is the first attempt in over 60 years to inspect the local mosquito population for any changes in either species richness or space-time dynamics. Introduction Figure 1: In 2013, the period from the end of May to the beginning of June had the highest values of species richness (N= 682). Estonia is a small country in Northern Europe, which is mainly influenced by a humid continental climate. Total area: 45,339 km2 Population: 1,311,759 Average annual temp.: 5.2 °C Average elevation: 50 m Republic of Estonia Testing our sampling methods in a well-defined environment. Studying: diversity and space-time dynamics of mosquito populations in an urban environment. Objectives Figure 2: In 2013, most Aedes and Ochlerotatus species were primarily active in late spring and early summer, while mosquitoes from the genus Culex became more prominent during the second half of the study period (N= 682). Majority of the study was conducted in 2013. 6 main and 3 additional sites were selected for surveillance in the town of Tartu. Mosquitoes were collected with a bug net, performing 2 sets of 25 sweeps in each location. Samples were gathered weekly from May to September.   Additional specimens were collected throughout the summer of 2015, using Mosquito Magnet traps. Mosquito species were mainly identified by morphological characteristics, but DNA sequencing of the CO1 region was used in some cases. However, 20 of the captured mosquitoes remain unidentified. Methods The town of Tartu contains diverse environments, from humid floodplains to busy streets. Yet, neither species diversity nor mosquito abundance were influenced by sampling sites. Meaning, that the local mosquito population might be mostly homogeneous. However, species composition changed considerably over time. The periods of greatest diversity were most likely transitional phases, when the previously dominant groups made way for later species. Our findings coincide with the knowledge, that adults of the genera Aedes and Ochlerotatus achieve maximum numbers earlier in the season than those of Culex. Discussion Tartu, the second largest urban environment in Estonia, is built around the river “Emajõgi”. The sampling sites were positioned on both sides of the waterway, in the shaded parts of frequently used areas. Sampling sites This study was supported by the MSc funding for V. Burtin, the Developmental Fundings of Estonian University of Life Sciences, project no M14143VLVP and by institutional research funding IUT21-1 of the Estonian Ministry of Education and Research.