Kearns CA (2001) North American dipteran pollinators: assessing their value and conservation status. Jarlan A, de Oliveira D, Gingras J (1997) Pollination by Eristalis tenax (Diptera: Syrphidae) and seed set of greenhouse sweet pepper.

Hoyle M, Cresswell JE (2006) Remobilization of initially deposited pollen grains has negligible impact on gene dispersal in bumble bee-pollinated Brassica napus. Hayter KE, Cresswell JE (2006) The influence of pollinator abundance on the dynamics and efficiency of pollination in agricultural Brassica napus: implications for landscape-scale gene dispersal. Goulson D, Wright NP (1998) Flower constancy in the hoverflies Episyrphus balteatus (Degeer) and Syrphus ribesii (L.) (Syrphidae). Goodman R, Hepworth G, Kaczynski P, McKee B, Clarke S, Bluett C (2001) Honeybee pollination of buckwheat ( Fagopyrum esculentum Moench) cv. Ghazoul J (2005) Buzziness as usual? Questioning the global pollination crisis. PLoS Biol 4:129вЂ“135ДЇrank T (1999) Density of adult hoverflies (Dipt., Syrphidae) in sown weed strips and adjacent fields. Oikos 108:465вЂ“472ДЇontaine C, Dajoz I, Meriguet J, Loreau M (2006) Functional diversity of plant-pollinator interaction webs enhances the persistence of plant communities. Field Crops Res 67:35вЂ“49Д®nfjГ¤ll K, Leimar O (2005) Density-dependent dispersal in the Glanville fritillary, Melitaea cinxa. Island Press, Washington, DCДiepenbrock W (2000) Yield analysis of winter oilseed rape ( Brassica napus L.): a review. Nature 387:253вЂ“260Дaily G (1997) NatureвЂ™s services: societal dependance on natural ecosystems. Island Press, Washington, DCД¬ostanza R, dвЂ™Arge R, deGroot R, Farber S, Grasso M, Hannon B, Limburg K, OвЂ™Naeem S, OвЂ™Neill RV, Paruelo J, Raskin RG, Sutton P, van den Belt M (1997) The value of the worldвЂ™s ecosystem services and natural capital. Science 313:351вЂ“354Д«uchmann SL, Nabhan GP (1997) The forgotten pollinators. Entomol Exp Appl 87:245вЂ“254Д«iesmeijer JC, Roberts SPM, Reemer M, Ohlemuller R, Edwards M, Peeters T, Schaffers AP, Potts SG, Kleukers R, Thomas CD, Settele J, Kunin WE (2006) Parallel declines in pollinators and insect-pollinated plants in Britain and the Netherlands. Conserv Biol 12:8вЂ“17Д«argen H, Saudhof K, Poehling HM (1998) Prey finding by larvae and adult females of Episyrphus balteatus. Thus, models ignoring the modulating effect of biotic interactions by generally assuming a simple positive relationship between pollinator density and pollination efficiency might not apply to a vital component of the pollinator community.ДЄllen-Wardell G, Bernhardt P, Bitter R, Burquez A, Buchmann S, Cane J, Cox PA, Dalton V, Feinsinger P, Ingram M, Inouye D, Jones CE, Kennedy K, Kevan P, Koopowitz H, Medellin R, Medellin-Morales S, Nabhan GP, Pavlik B, Tepedino V, Torchio P, Walzer S (1998) The potential consequences of pollinator declines on the conservation of biodiversity and stability of food crop yields. This suggests adverse effects of density-dependent factors on pollination efficiency at high densities. balteatus was lower at high pollinator densities than at low pollinator densities. It highlights the important role of hover flies as pollinators of arable crops under varying environmental conditions. This effect was very constant in the 2В years, despite considerable interannual differences in total seed numbers and seed mass. balteatus significantly increased both seed set and yield. The study was conducted over a period of 2 consecutive years by means of enclosure experiments at an agricultural site located in Central Hesse (Germany). We investigated the pollination efficiency of the globally abundant hover fly Episyrphus balteatus on the common crop, oilseed rape ( Brassica napus). However, most studies on this issue focus on bees, while other invertebrate taxa are largely ignored.

Understanding the consequences of declining diversity and abundance of pollinators for crops and floral biodiversity is a major challenge for current conservation ecology.

Hover flies