The significance of pollination is often expressed in economic terms – the assumed losses to the GDP of a state if no pollination of agricultural crops occurred.
Two recent international studies have taken the approach of estimating the impacts in relation to the nutritional needs of the human population.
Contribution of Pollinator-Mediated Crops to Nutrients in the Human Food Supply
Authors: Elisabeth J. Eilers, Claire Kremen, Sarah Smith Greenleaf, Andrea K. Garber,
Journal: PLoS ONE (2011) Vol 6 no. 6: e21363
Contribution of wild pollinators to food crop pollination
Garibaldi et al, Science], Feb 2013