Abstract:1. Pollination is an important ecosystem service as many agricultural crops such as fruit trees are pollinated by insects. Agricultural intensification, however, is one of the main drivers resulting in a serious decline of pollinator populations worldwide. 2. In this study pollinator communities were examined in twelve apple orchards surrounded by either homogeneous or heterogeneous landscape in Hungary. Pollinators (honey bees, wild bees, hoverflies) were surveyed in the flowering period of apple trees. Landscape heterogeneity was characterized in circles of 300, 500 and 1000 m radius around each orchard using Shannon's diversity and Shannon's evenness indices. 3. We found that pollination success of apple was significantly related to the species richness of wild bees, regardless the dominance of honey bees. 4. Diversity of the surrounding landscape matrix had a marginal positive effect on the species richness of hoverflies at 300m, positive effect on the species richness of wild bees at 500m radius circle, while evenness of the surrounding landscape enhanced the abundance of wild bees at 500m radius circle. Flower resources in the groundcover within the orchards supported honey bees. 5. Therefore maintenance of semi-natural habitats within 500m around apple orchards is highly recommended to enhance wild pollinator communities and apple production. Apple is one of the most important insect pollinated crops in the European Union, accounting 51 for 16% of the EU's total economic gains attributed to insect (particularly bee) pollination 52 (Leonhardt et al., 2013). Most apple varieties are cross-pollinated and insect pollination not 53 only affects the quantity of apple production, but can also have marked impacts on the quality 54 of the fruits, influencing size, shape and their market price (Garratt et al., 2014a). The most 55 common insect pollinator of apple is the honey bee (Apis mellifera); however, it is not the bees (Bosch & Blas, 1994). Hoverflies (Syrphidae) have also been observed with pollen loads 63 containing a high proportion of compatible fruit pollen (Kendall, 1973). Agricultural and Forest Entomology 64In the temperate zone, pollinator insects are under threat from a number of limiting 65 factors, such as climate change (Rader et al., 2013), human disturbance (Goulson et al., 66 2008), agricultural intensification (Kearns et al., 1998; Steffan-Dewenter et al., 2005; 67 Fitzpatrick et al., 2006; Memmott et al., 2007), and landscape fragmentation (Aizen & 68 Feisinger, 2003; Diekötter & Crist, 2013), which leads to less effective pollination and 69 reduces agricultural production (Floyd, 1992; Garibaldi et al., 2011a Garibaldi et al., , 2013 (Kremen et al., 2002; Brittain et al., 2013). Maintaining diverse communities, 94Apple is the most important fruit tree in Hungary, as it provides 60 % of the total 95Hungarian fruit production, and currently amounts to 400-600 thousand tons annually on We constructed generalized linear mixed models (GLMM) for each response variab...

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The ecology of West Nile virus (WNV) in the Danube Delta Biosphere Reserve (Romania) was investigated by combining studies on the virus genetics, phylogeography, xenosurveillance and host-feeding patterns of mosquitoes. Between 2014 and 2016, 655,667 unfed and 3842 engorged mosquito females were collected from four sampling sites. Blood-fed mosquitoes were negative for WNV-RNA, but two pools of unfed Culex pipiens s.l./torrentium collected in 2014 were tested positive. Our results suggest that Romania experienced at least two separate WNV lineage 2 introductions: from Africa into Danube Delta and from Greece into south-eastern Romania in the 1990s and early 2000s, respectively. The genetic diversity of WNV in Romania is primarily shaped by in situ evolution. WNV-specific antibodies were detected for 19 blood-meals from dogs and horses, but not from birds or humans. The hosts of mosquitoes were dominated by non-human mammals (19 species), followed by human and birds (23 species). Thereby, the catholic host-feeding pattern of Culex pipiens s.l./torrentium with a relatively high proportion of birds indicates the species’ importance as a potential bridge vector. The low virus prevalence in combination with WNV-specific antibodies indicate continuous, but low activity of WNV in the Danube Delta during the study period.