Pollination is the transfer of pollen grains from the male part of the flower to the female part of the flower. This transfer vector for the pollen grains can be the wind (for light pollen grains), ants, bats, bees, birds, butterflies, flies, etc. In most cases the most efficient is the honey bee.
For more information on Pollination go to http://en.wikipedia.org/wiki/Pollination
Pollination not only determines the quantity of fruit, but with many crops pollination has a large impact on the quality as well.
Pollination is the most critical event in the calendar of an orchardist or horticulturalist. Fruit can not be added at a later date – pollination has to occur at flowering regardless of the weather. While in Australia feral honey bees can provide pollination, in periods of cold wet weather the feral bees may not fly the required distance to the orchard/crop.
One way to remove this gamble is to have paid pollination units in the orchard.
Providing the temperature is above 13ºc honey bees within the orchard will pollinate some of the crop. As the temperature rises so will the distance that bees will travel from the hive to gather pollen and nectar – which pollinates the flowers.