Commercial bees

There were enough pollinators around for my garden this year, and I enjoyed watching them searching for flowers and doing their job. In fact I wished there were more flowers in the garden throughout the season. However, there are clearly not enough bees around to pollinate all the orchard fruit, for on the TV there is a show called Harvest 2013, which showed boxes of bees being unloaded into the poly tunnels full of cherry trees to do their job. These bees have been laboratory bred and housed in cardboard boxes for the journey from Eastern Europe to the UK. When the blossom opens the bees are released, and they off and do their stuff. But it seems to me that there was no question that these bees would survive in the area long term. They were there solely as pollinators. They were not honey bees but probably a species of Megachilidae.

The Megachilidae Family
These types of bees are extremely efficient pollinators. This family includes mason and leafcutter bees. Some are used in commercial pollination, such as Alfalfa leafcutter bees (Megachile rotundata), and Osmia lignaria (the "Orchard Mason Bee" or "Blue Orchard Bee"), which is especially sold for use in orchard crop pollination. 
According to the U. S. Department of Agriculture researchers, only 250 female blue orchard bees (Osmia lignaria) are required to pollinate an acre of apples - a service equivalent to one or two honey bees hives, each containing 15,000 to 20,000 workers (Bosch and Kemp, 2001). 
It's possible to farm in harmony with nature, attract these bees to the land, which is better for crop yields. More about this shortly. 

This comes from a great website that tells you all about bees. Have a look!

The author is concerned that growers don't care about the ecosystem, and are giving up on attracting native bees to their growing area.

Here is an American website with more reservations about the use of commercial bees in the food industry. They threaten the local bumble bee population.

There are a number of threats facing bumble bees, any of which may be leading to the decline of these species. The major threats to bumble bees include: spread of pests and diseases through commercial bumble bee rearing or other methods, habitat destruction or alteration, pesticides, invasive species, low genetic diversity and climate change.

Commercial bumble bee rearing may be the greatest threat to B. affinis, B. occidentalis, B. terricola, and B. franklini. In North America, two bumble bee species have been commercially reared for pollination of greenhouse tomatoes and other crops: B. occidentalis and B. impatiens. Between 1992 and 1994, queens ofB. occidentalis and B. impatiens were shipped to European rearing facilities, where colonies were produced then shipped back to the U.S. for commercial pollination. Bumble bee expert Robbin Thorp has hypothesized that these bumble bee colonies acquired a disease (probably a virulent strain of the microsporidian Nosema bombi) from a European bee that was in the same rearing facility, the buff-tailed bumble bee (Bombus terrestris). The North American bumble bees would have had no prior resistance to this pathogen. Dr. Thorp hypothesizes that the disease then spread to wild populations of B. occidentalis andB. franklini in the West (from exposure to infected populations of commercially reared B. occidentalis), and B. affinis and B. terricola in the East (from exposure to commercially reared B. impatiens). In the late 1990′s, biologists began to notice that B. affinis, B. occidentalis, B. terricola, and B. franklini were severely declining.

Where these bees were once very common, they were nearly impossible to find. B. impatiens has not shown a dramatic decline; Robbin Thorp hypothesizes that B. impatiens may serve as a carrier of an exotic strain of Nosema bombi, although it may not be as severly affected by the disease as B. affinis, B. occidentalis, B. terricola, and B. franklini. B. affinis, B. occidentalis, B. terricola, and B. franklini are closely related to each other (they all belong to the subgenus Bombus sensu stricto).

This hypothesis was supported by a recent study led by Sydney Cameron, Ph.D., published in the Proceedings of the National Academy of Sciences. They found that the western bumble bee and the American bumble bee had significantly higher infection rates from a fungal parasite than more stable species.  They also found that these two species had lower genetic diversity than species that were not in decline.  Research is currently underway in Dr. Cameron’s lab to determine whether or not this fungal parasite was introduced from Europe via the commercial bumble bee trade. You can read more about their study and its implications here. The Xerces Society is currently working to urge the USDA Animal and Plant Health Inspection Service to regulate the commercial bumble bee trade. You can read a status review that includes more details on this issue and the decline of three bumble bees that was written by Dr. Robbin Thorp and The Xerces Society.