, 156:819 | Cite as

Hover flies are efficient pollinators of oilseed rape

Plant-Animal Interactions - Original Paper


Understanding the consequences of declining diversity and abundance of pollinators for crops and floral biodiversity is a major challenge for current conservation ecology. However, most studies on this issue focus on bees, while other invertebrate taxa are largely ignored. We investigated the pollination efficiency of the globally abundant hover fly Episyrphus balteatus on the common crop, oilseed rape (Brassica napus). 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). E. balteatus significantly increased both seed set and yield. This effect was very constant in the 2 years, despite considerable interannual differences in total seed numbers and seed mass. It highlights the important role of hover flies as pollinators of arable crops under varying environmental conditions. In contrast to bees, the effect of E. balteatus was lower at high pollinator densities than at low pollinator densities. This suggests adverse effects of density-dependent factors on pollination efficiency at high densities. 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.


Syrphidae Canola Pollination Generalists Brassica napus 


  1. Allen-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. Conserv Biol 12:8–17CrossRefGoogle Scholar
  2. Bargen H, Saudhof K, Poehling HM (1998) Prey finding by larvae and adult females of Episyrphus balteatus. Entomol Exp Appl 87:245–254CrossRefGoogle Scholar
  3. Biesmeijer 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. Science 313:351–354PubMedCrossRefGoogle Scholar
  4. Buchmann SL, Nabhan GP (1997) The forgotten pollinators. Island Press, Washington, DCGoogle Scholar
  5. Costanza R, d’Arge R, deGroot R, Farber S, Grasso M, Hannon B, Limburg K, O’Naeem S, O’Neill RV, Paruelo J, Raskin RG, Sutton P, van den Belt M (1997) The value of the world’s ecosystem services and natural capital. Nature 387:253–260CrossRefGoogle Scholar
  6. Daily G (1997) Nature’s services: societal dependance on natural ecosystems. Island Press, Washington, DCGoogle Scholar
  7. Diepenbrock W (2000) Yield analysis of winter oilseed rape (Brassica napus L.): a review. Field Crops Res 67:35–49CrossRefGoogle Scholar
  8. Enfjäll K, Leimar O (2005) Density-dependent dispersal in the Glanville fritillary, Melitaea cinxa. Oikos 108:465–472CrossRefGoogle Scholar
  9. Fontaine C, Dajoz I, Meriguet J, Loreau M (2006) Functional diversity of plant-pollinator interaction webs enhances the persistence of plant communities. PLoS Biol 4:129–135CrossRefGoogle Scholar
  10. Frank T (1999) Density of adult hoverflies (Dipt., Syrphidae) in sown weed strips and adjacent fields. J Appl Entomol 123:351–355CrossRefGoogle Scholar
  11. Ghazoul J (2005) Buzziness as usual? Questioning the global pollination crisis. Trends Ecol Evol 20:367–373PubMedCrossRefGoogle Scholar
  12. Goodman R, Hepworth G, Kaczynski P, McKee B, Clarke S, Bluett C (2001) Honeybee pollination of buckwheat (Fagopyrum esculentum Moench) cv. Manor. Aust J Exp Agric 41:1217–1221CrossRefGoogle Scholar
  13. Goulson D, Wright NP (1998) Flower constancy in the hoverflies Episyrphus balteatus (Degeer) and Syrphus ribesii (L.) (Syrphidae). Behav Ecol 9:213–219CrossRefGoogle Scholar
  14. 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. J Appl Ecol 43:1196–1202CrossRefGoogle Scholar
  15. Hoyle M, Cresswell JE (2006) Remobilization of initially deposited pollen grains has negligible impact on gene dispersal in bumble bee-pollinated Brassica napus. Funct Ecol 20:958–965CrossRefGoogle Scholar
  16. Jarlan A, de Oliveira D, Gingras J (1997) Pollination by Eristalis tenax (Diptera: Syrphidae) and seed set of greenhouse sweet pepper. J Econ Entomol 90:1646–1649Google Scholar
  17. Kearns CA (2001) North American dipteran pollinators: assessing their value and conservation status. Conserv Ecol 5. Online URL:http://www.consecol.org/vol5/iss1/art5/
  18. Kearns CA, Inouye DW, Waser NM (1998) Endangered mutualisms: the conservation of plant-pollinator interactions. Annu Rev Ecol Syst 29:83–112CrossRefGoogle Scholar
  19. Kendall DA, Wilson D, Guttridge CG, Anderson HM (1971) Testing Eristalis as a pollinator of covered crops. Long Ashton Res Stn Rep 1971:120–121Google Scholar
  20. Klein AM, Vaissiére BE, Cane JH, Steffan-Dewenter I, Cunningham SA, Kremen C, Tscharntke T (2007) Importance of pollinators in changing landscapes for world crops. Proc R Soc Lond B Biol 274:303–313CrossRefGoogle Scholar
  21. Kremen C, Williams NM, Thorp RW (2002) Crop pollination from native bees at risk from agricultural intensification. Proc Natl Acad USA 99:16812–16816CrossRefGoogle Scholar
  22. Kremen C, Williams NM, Bugg RL, Fay JP, Thorp RW (2004) The area requirements of an ecosystem service: crop pollination by native bee communities in California. Ecol Lett 7:1109–1119CrossRefGoogle Scholar
  23. Kristen R (2008) Entomofauna an Raps: Verteilung, Bestäubung und ökologische Bedeutung in der Kulturlandschaft. Ph.D. thesis, Department of Animal Ecology, Justus Liebig University Giessen, GermanyGoogle Scholar
  24. Larson BMH, Kevan PG, Inouye DW (2001) Flies and flowers: taxonomic diversity of anthophiles and pollinators. Can Entomol 133:439–465CrossRefGoogle Scholar
  25. MacLeod A (1999) Attraction and retention of Episyrphus balteatus DeGeer (Diptera: Syrphidae) at an arable field margin with rich and poor floral resources. Agric Ecosyst Environ 73:237–244CrossRefGoogle Scholar
  26. Morandin LA, Winston ML (2005) Wild bee abundance and seed production in conventional, organic, and genetically modified canola. Ecol Appl 15:871–881CrossRefGoogle Scholar
  27. Morandin LA, Winston ML (2006) Pollinators provide economic incentive to preserve natural land in agroecosystems. Agric Ecosyst Environ 116:289–292CrossRefGoogle Scholar
  28. Nye WP, Anderson JL (1974) Insect pollinators frequenting strawberry blossoms and the effect of honeybees on yield and fruit quality. J Am Soc Hortic Sci 99:40–44Google Scholar
  29. Pineda A, Morales I, Marcos-García MA, Fereres A (2007) Oviposition avoidance of parasitized aphid colonies by the syrphid predator Episyrphus balteatus mediated by different cues. Biol Control 42:274–280CrossRefGoogle Scholar
  30. Richards AJ (2001) Does low biodiversity resulting from modern agricultural practice affect crop pollination and yield? Ann Bot Lond 88:165–172CrossRefGoogle Scholar
  31. Ricketts TH (2004) Tropical forest fragments enhance pollinator activity in nearby coffee crops. Conserv Biol 18:1262–1271CrossRefGoogle Scholar
  32. Sahli HF, Conner JK (2006) Characterizing ecological generalization in plant-pollination systems. Oecologia 148:365–372PubMedCrossRefGoogle Scholar
  33. Schittenhelm S, Gladis T, Rao VR (1997) Efficiency of various insects in germplasm regeneration of carrot, onion and turnip rape accessions. Plant Breed 116:369–375CrossRefGoogle Scholar
  34. Solomon ME, Kendall DA (1970) Pollination by the syrphid fly, Eristalis tenax. Long Ashton Res Stn Rep 1970:101–102Google Scholar
  35. Speight MCD (2006) Species accounts of European Syrphidae (Diptera), Ferrara 2006. In: Speight MCD, Castella E, Sarthou J-P, Monteil C (eds) Syrph the Net on CD, Issue 5. The database of European Syrphidae. Syrph the Net Publications, DublinGoogle Scholar
  36. Statistisches Bundesamt (2005) Land- und Forstwirtschaft. Wachstum und Ernte—Feldfrüchte. Fachserie 3/Reihe 3.2.1Google Scholar
  37. Steffan-Dewenter I (2003) Seed set of male-sterile and male-fertile oilseed rape (Brassica napus) in relation to pollinator density. Apidologie 34:227–235CrossRefGoogle Scholar
  38. Steffan-Dewenter I, Potts SG, Packer L (2005) Pollinator diversity and crop pollination services are at risk. Trends Ecol Evol 20:651–652PubMedCrossRefGoogle Scholar
  39. Sugiura N (1996) Pollination of the orchid Epipactis thunbergii by syrphid flies (Diptera: Syrphidae). Ecol Res 11:249–255CrossRefGoogle Scholar
  40. Sutherland JP, Sullivan MS, Poppy GM (2001) Distribution and abundance of aphidophagous hoverflies (Diptera: Syrphidae) in wildflower patches and field margins. Agric For Entomol 3:57–64CrossRefGoogle Scholar
  41. Tenhumberg B, Poehling HM (1995) Syrphids as natural enemies of cereal aphids in Germany—aspects of their biology and efficacy in different years and regions. Agric Ecosyst Environ 52:39–43CrossRefGoogle Scholar
  42. Vance NC, Bernhardt P, Edens RM (2004) Pollination and seed production in Xerophyllum tenax (Melanthiaceae) in the Cascade Range of Central Oregon. Am J Bot 91:2060–2068CrossRefGoogle Scholar
  43. Waser NM, Chittka L, Price MV, Williams N, Ollerton J (1996) Generalization in pollinator systems, and why it matters. Ecology 77:279–296Google Scholar
  44. Westcott L, Nelson D (2001) Canola pollination: an update. Bee World 82:115–129Google Scholar
  45. Westrich P (1989) Die Wildbienen Baden-Württembergs. Ulmer, StuttgartGoogle Scholar

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  1. 1.Department of Animal EcologyJustus Liebig UniversityGiessenGermany

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