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Promoting habitat gardening for bees

04/10/2010
Martha Proctor

One-third of the world's food supply depends on bees for pollination. Every year in California alone, honeybees pollinate more than 100 crops worth more than $6 billion, including vegetables, nuts (notably almonds), fruit and wildflowers. Colony Collapse Disorder (CCD) is the phenomenon in which worker bees from a beehive or from a colony of European honeybees, Apis mellifera, suddenly disappear. CCD has wiped out a third of the honeybees in the United States since it was first reported in 2004. The good news is that the number of reported cases of CCD in the nation dropped considerably over the winter of 2008-09.

Of about 4,000 bee species in the United States, approximately 1,600 have been recorded in California. Gordon Frankie, a native bee expert, and his team of researchers from UC Berkeley and UC Davis are promoting habitat gardening for bees using targeted ornamental plants, mostly natives, to promote native bee populations and diversity.

Frankie and others discovered that as many as 82 bee species frequent Bay Area gardens; 78 percent of these species are native bees, while only four species, one of which was the European honeybee, are non-native. His Web site, www.nature.berkeley.edu/urbanbeegardens, provides information about bees and a list of bee-friendly flowers. He recommends that gardeners interested in creating a bee-habitat garden plant large patches of a diversity of mostly native and bee-friendly flowers. As mulch deters native bees from digging their nests, Frankie recommends that some areas in gardens be left mulch-free so bees can readily create their nesting burrows.

Since 2006, researchers all over the world have been studying CCD to determine its cause and identify methods to prevent and combat honeybee diseases. The more than 200 proposed hypotheses range from counterproductive beekeeper management practices; nutritional deficits associated with forcing bees to pollinate a series of monoculture crops; the toxic byproduct of feeding high fructose corn syrup to supplement bees' diet in winter; and the use of chemicals, e.g., pesticides and antibiotics applied to treat parasites, infections and viruses.

Other factors include the stress induced by long-distance hauling of bee colonies from crop to crop across the country (an average of 5,500 miles a year), climate change, the artificial insemination of queens, loss of habitat and a lack of genetic diversity. All of the many suspected factors have the potential to upset the balance within the hive, result in diminished immunity of bees to pathogens or both. Although the cause of CCD is still unknown, research has given credence to the hypothesis that CCD may be a syndrome caused by many factors, working together in combination or synergistically. Interestingly, two years after honeybees started to disappear, bats populations also began to decline.

The weakened bee industry seriously affects commercial beekeepers, limits the diversity of crops available to consumers and increases costs to growers and consumers alike. Some experts hypothesize that if current destructive commercial beekeeping practices continue, the population of bees will be wiped out by 2035. Accordingly, many experts think that CCD could spell disaster for the agriculture industry because of its reliance on honeybees as pollinators and the increasing demand on bees for their services. Growers rent close to 2 million colonies a year to service more than 90 crops. Pollination of California's almond crop requires 1.3 million colonies (about 40 billion honey bees) and is predicted to require 2.12 million colonies by 2012 (about 95 percent of all colonies in the United States).

Although commercial beekeepers have suffered the most, Bay Area beekeepers have also sustained losses. In an effort to reverse their losses, local beekeepers are working to breed a better bee in a concerted effort to save their remaining hives. To produce their own drug-free queens, a few Marin County beekeepers are breeding queens that are able to detect a hive infested with mites and other pathogens, kill and remove the damaged brood, and thus protect the rest of the hive from infection. Also, University of California researchers are selectively breeding bees that hoard pollen, as this trait enables these bees to maintain their nutritional requirements over the winter and concomitantly protects them from succumbing to CCD.

Mea McNeil-Draper, an expert beekeeper in San Anselmo, noted that until recently, beekeepers tried to keep their hives clear of propolis, a sticky substance made from tree resin that bees use to coat the inside of their hives. Propolis acts as a barrier against bacteria, mold and viruses but because it adds to the difficulty of getting into a hive, beekeepers for the past 150 years have selected bees that propolize only in small amounts.

To learn more about bee-friendly gardening, visit the farm at the College of Marin's Indian Valley campus. Bethallyn Black, the farm manager, working with Steve Smart, a local organic bee grower, is installing five beehives, each with an organic queen bee and pheromone to attract feral male drones from untreated hives. These hives will not be sprayed with toxic chemicals for pathogens, such as mites. The goal is to breed queens with feral males in the midst of myriad flowers and vegetables attractive to bees on this productive organic farm. The mix of pollens available in the farm's garden will provide the building blocks for the best bee diet and most robust bees. It's hoped this type of endeavor will inspire beekeepers in other parts of the country and world to raise bees without the use of pesticides, herbicides or other unnatural or harmful substances, so that bee populations will begin to be restored to their former health.

The University of California Marin Master Gardeners are sponsored by UC Cooperative Extension. For questions about gardening, plant pests or diseases, call 499-4204 from 9 a.m. to noon, and 1 to 4 p.m. weekdays, or bring in samples or pictures to 1682 Novato Blvd., Suite 150B, Novato.

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