“In 1945 there were 4.5 million bee hives in the U.S. Today, there are just about 2 million. We average a 30 percent loss of beehives in winter each year. Twenty years ago that was 15 percent.”
So reports Dr. Marla Spivak, entomologist, University of Minnesota Bee Lab in a 2013 Ted Talks presentation. She says there are 20,000 species of bees in world. Most live in the ground or in hollow stems rather than in social colonies as honeybees do. Within a colony, bees have natural defenses that have kept them thriving for over 50 million years. However, seven years ago, bees started dying from multiple, interacting causes: disease-causing parasites, monocultures of plants, pesticide contamination, flowerless landscapes and a dysfunctional food system.
In the U.S., bee numbers have been declining since World War II when we changed our farming practices. We stopped planting clover and alfalfa cover crops, which were an excellent food source for bees and started using synthetic fertilizers instead. We began applying more herbicides, killing weeds whose flowers were a food source for bees. Now farms are agricultural food deserts for bees, because they are usually dominated by single species (monoculture) of plants. For example, even though almond flowers are a good pollen source for bees, over 1.5 million hives must be transported across the country to pollinate tens of thousands of acres of almonds. Nothing else is growing, just almonds. The bees are trucked in on semis and trucked out after pollination, since at that point, there is no more food for them.
After World War II, farmers also increased their use of fungicides and insecticides, in addition to herbicides. Researchers at Penn State University have been studying pesticide residues in the pollen bees are carrying home. They found that every batch of pollen in their study had about six pesticides in it, including not only the toxic active ingredients in the herbicides, fungicides, insecticides, but also the inert ingredients that can be more toxic than actual chemical.
What can we as gardeners do? We can plant bee-friendly flowers, particularly native plants that bloom in each season. We can avoid pesticide contamination, at least in our own yards. We can ask that pollen sources be planted in parks, open spaces, along roadsides, etc. We can give bees access to good nutrition, which will allow them to take care of their own health. We can be a bee friendlier society.
For more information, go to http://www.ted.com/talks/marla_spivak_why_bees_are_disappearing?language=en.
JoAnne Skelly is the Carson City/Storey County Extension educator for University of Nevada Cooperative Extension and may be reached at skellyj@unce.unr.edu or 887-2252.