The United States Department of Agriculture reports that bees pollinate eighty-percent of flowering crops. That translates into about one-third of our diet. If it were not for bees, we would have no broccoli, apples, asparagus, nuts, blueberries, strawberries, or cucumbers. Perhaps more importantly, we would have no alfalfa, which would jeopardize our dairy and beef industries. Cornell University recently released a study showing that $14 billion of crops and seeds in the U.S. owe their existence to honeybee pollination.
Honeybee pollination happens when the bees transfer pollen from one flower’s anthers to another flower’s stigma. When the pollen reaches the stigma, it produces a pollen tube that grows downward through the style to the ovary where the flower’s eggs are located. The eggs are fertilized, seeds are formed, and the plant is able to reproduce.
Each act of pollination falls into one of two major categories. In the first place, self-pollination occurs when the flower producing the pollen and the flower receiving the pollen are of the same genetic constitution. When the two flowers are of a different genetic makeup, cross-pollination, otherwise known as allogamy, occurs. Plants that are able to pollinate themselves to reproduce are called self-fertile while those that cannot pollinate themselves are called self-sterile. Self-sterile plants require cross-pollination to produce each new generation and perpetuate their existence on the earth.
For example, peaches are self-fertile since they can produce a commercial crop without cross-pollination. However, they do produce a larger crop when cross-pollinated. Apples, however, must be cross-pollinated if they are to produce a commercial crop. Many apple growers have learned that they must graft a limb of a pollinizer (usually a crabapple) into roughly every sixth tree.
The problem is getting the pollen from the one plant to the other plant, in order to achieve cross-pollination. Though wind plays a part, the main answer is the honeybee. However, when a bee finds a tree with thousands of blossoms on it, the bee will often do all of its pollen and nectar collection from that one tree, ignoring all the other trees. So how does the honeybee spread pollen between trees? The answer is found back at the beehive as all the bees crowd together into a small space. Close quarters means lots of contact between bees, which in turn leads to transfer of pollen between bees. Thus a bee visits a Red Delicious apple tree, gathers pollen, and returns to the hive. There, he might rub that pollen off on another bee who then returns to his Granny Smith tree. Cross-pollination occurs, and there will be Granny Smith apples this spring!
Occasionally the honeybee will even cross-pollinate a variety of organic vegetables with genetically engineered pollen. There are currently many questions that surround cross-pollination between genetically modified organisms and organic organisms. For example, is a famer who plants genetically engineered crops that cross-pollinate with his neighbor’s organic crops guilty of trespassing and liable?
Regardless of the answers to these kinds of questions, the facts are that this cross-pollination between organic and non-organic crops is already happening. Tests performed by Successful Farming magazine have discovered cross-pollination of genetically engineered crops in corn and soybeans that were grown by organic standards. In a world where genetically modified organisms are becoming more and more common, this is a serious issue to consider and perhaps confront. If honeybees can bring pollen from genetically modified crops directly into an organic farmer’s crops, then eventually no crops will be one hundred percent organic.
At any rate, the bees are doing us a major service in cross-pollinating the organic vegetables that could not reproduce otherwise. Our goal must be to understand and carefully monitor that process.