@article{KlattHolzschuhWestphaletal.2014,
  author    = {Klatt, Bj{\"o}rn K. and Holzschuh, Andrea and Westphal, Catrin and Clough, Yann and Smit, Inga and Pawelzik, Elke and Tscharntke, Teja},
  title     = {Bee pollination improves crop quality, shelf life and commercial value},
  series = {Proceedings of the Royal Society B: Biological Sciences},
  volume    = {281},
  journal   = {Proceedings of the Royal Society B: Biological Sciences},
  number    = {1775},
  doi       = {10.1098/rspb.2013.2440},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120797},
  year      = {2014},
  abstract  = {Pollination improves the yield of most crop species and contributes to one-third of global crop production, but comprehensive benefits including crop quality are still unknown. Hence, pollination is underestimated by international policies, which is particularly alarming in times of agricultural intensification and diminishing pollination services. In this study, exclusion experiments with strawberries showed bee pollination to improve fruit quality, quantity and market value compared with wind and self-pollination. Bee-pollinated fruits were heavier, had less malformations and reached higher commercial grades. They had increased redness and reduced sugar-acid-ratios and were firmer, thus improving the commercially important shelf life. Longer shelf life reduced fruit loss by at least 11\%. This is accounting for 0.32 billion US\$ of the 1.44 billion US\$ provided by bee pollination to the total value of 2.90 billion US\$ made with strawberry selling in the European Union 2009. The fruit quality and yield effects are driven by the pollination-mediated production of hormonal growth regulators, which occur in several pollination-dependent crops. Thus, our comprehensive findings should be transferable to a wide range of crops and demonstrate bee pollination to be a hitherto underestimated but vital and economically important determinant of fruit quality.},
  language  = {en}
}
@article{BartomeusPottsSteffanDewenteretal.2014,
  author    = {Bartomeus, Ignasi and Potts, Simon G. and Steffan-Dewenter, Ingolf and Vaissiere, Bernard E. and Woyciechowski, Michal and Krewenka, Kristin M. and Tscheulin, Thomas and Roberts, Stuart P. M. and Szentgyoergyi, Hajnalka and Westphal, Catrin and Bommarco, Riccardo},
  title     = {Contribution of insect pollinators to crop yield and quality varies with agricultural intensification},
  series = {PEERJ},
  volume    = {2},
  journal   = {PEERJ},
  number    = {e328},
  issn      = {2167-9843},
  doi       = {10.7717/peerj.328},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-116928},
  year      = {2014},
  abstract  = {Background. Up to 75\% of crop species benefit at least to some degree from animal pollination for fruit or seed set and yield. However, basic information on the level of pollinator dependence and pollinator contribution to yield is lacking for many crops. Even less is known about how insect pollination affects crop quality. Given that habitat loss and agricultural intensification are known to decrease pollinator richness and abundance, there is a need to assess the consequences for different components of crop production. Methods. We used pollination exclusion on flowers or inflorescences on a whole plant basis to assess the contribution of insect pollination to crop yield and quality in four flowering crops (spring oilseed rape, field bean, strawberry, and buckwheat) located in four regions of Europe. For each crop, we recorded abundance and species richness of flower visiting insects in ten fields located along a gradient from simple to heterogeneous landscapes. Results. Insect pollination enhanced average crop yield between 18 and 71\% depending on the crop. Yield quality was also enhanced in most crops. For instance, oilseed rape had higher oil and lower chlorophyll contents when adequately pollinated, the proportion of empty seeds decreased in buckwheat, and strawberries' commercial grade improved; however, we did not find higher nitrogen content in open pollinated field beans. Complex landscapes had a higher overall species richness of wild pollinators across crops, but visitation rates were only higher in complex landscapes for some crops. On the contrary, the overall yield was consistently enhanced by higher visitation rates, but not by higher pollinator richness. Discussion. For the four crops in this study, there is clear benefit delivered by pollinators on yield quantity and/or quality, but it is not maximized under current agricultural intensification. Honeybees, the most abundant pollinator, might partially compensate the loss of wild pollinators in some areas, but our results suggest the need of landscape-scale actions to enhance wild pollinator populations.},
  language  = {en}
}