Ensuring food supplies

The science of pollination and crop survival

Original URL: http://report.president.msu.edu/2008/content/ensuring.php

It’s estimated that one of every three bites of food consumed in the world is made possible by pollinators. But in recent years, honeybees—the powerhouses of agricultural pollination—have been disappearing at alarming rates, leaving beekeepers and scientists perplexed.

With as much as 80 percent of Earth’s crops at stake, MSU entomologists in the College of Natural Science and the College of Agriculture and Natural Resources are seeking rapidly deployable solutions for protecting honeybees from colony collapse disorder (CCD), the complex disease that is characterized by the disappearance of all adult honeybees in a hive, while also finding new ways to attract other pollinators to help ensure crop survival.

Solving the pollinator puzzle

The decimation of honeybee populations throughout the nation became a widespread problem for beekeepers in 2006, and by 2007 the entire agriculture industry was aware of the crisis. The winged workers are the main pollinators for hundreds of crops grown in the United States, including almonds, blueberries, apples, avocados, cherries, and broccoli. The value of honeybees as commercial pollinators is estimated at about $15 billion nationally. In Michigan alone, about $455 million worth of crops each year depend on bees for pollination.

MSU entomologist Zachary Huang says that pinpointing the cause of honeybee losses is difficult because it is believed that multiple factors are involved. The Varroa mite is a chief enemy of the honeybee, and hives have suffered significantly from outbreaks in the past few years, but it’s not the only culprit in colony collapse. The substantial honeybee losses remain a mystery to researchers, although some suspected causes have been ruled out.

In the winter of 2008, a survey by the U.S. Department of Agriculture–Agricultural Research Services reported 36 percent of America’s 2.4 million hives were lost to CCD. The survey covered almost 20 percent of America’s 1,500 commercial beekeepers and suggested an additional loss of 11 percent over those in 2007 and 40 percent over the losses in 2006.

Although beekeepers have been able to manage hives in ways that have helped honeybee populations remain relatively stable in some years despite heavy losses, sustainability is at risk.

“Honeybee populations can be quickly increased by ‘dividing’ an existing healthy colony into two, essentially doubling the existing population,” says Huang. “This is why we were doing okay in some years even when we lost half of our bees during the winter. However, if CCD keeps killing 30 percent to 40 percent of total bees per year, it might become unsustainable in the long run because dividing colonies could itself create more stress.”

Huang is focusing his latest research on the parasite Nosema, which may play a role in the inability of honeybees to return to their hives. Researchers in a number of countries, including Spain, France, and China, suspect this species may be the cause of their massive bee deaths.

“My research will provide answers to a subset of questions, similar to contributing a piece to solving a large puzzle,” says Huang. “Even if we do not find the cause of CCD, our research will still help beekeepers in Michigan, across the country, and internationally.”

Huang’s current research is funded by the U.S. Department of Agriculture. His research on colony collapse disorder that began in 2007 was supported by MSU’s Project GREEEN (Generating Research and Extension to meet Economic and Environmental Needs) and the Michigan Agricultural Experiment Station.

Identifying alternative pollinators

On another front in the effort to ensure the survival of crops that rely on pollination, MSU entomologists Rufus Isaacs and Doug Landis and a team of graduate students are working to make Michigan landscapes more attractive to other pollinators that can pick up where honeybees leave off.

In 2003—before pollinator decline hit headlines—Isaacs and Landis received a U.S. Department of Agriculture grant and began using native plants to attract natural enemies of insects that attack crops. These enemies, including lady beetles and parasitic wasps, allow growers to control pest insects without chemicals that are harmful to honeybees. The team received a second round of funding to expand the project and determine which plants are most attractive to various species of pollinators. They chose to test native prairie and savanna plants that, although once abundant, are now quite rare. Currently, the researchers are conducting field trials over a several-year period to determine whether more natural enemies and pollinators are attracted to crops that are bordered by these native plants.

MSU pollinator studies have been influenced by research on biofuel crops that Landis is conducting with the Great Lakes Bioenergy Research Center, a national center funded by the U.S. Department of Energy, in which MSU is a partner.

“As we grow mixed biofuel crops in Michigan, we’re finding that we’re attracting the beneficial insects at the same time, so it’s a win–win,” says Landis. “The more diverse the biofuel crops we grow here, the greater the number of beneficial insects and pollinators.”

Creating a buzz

Currently, Landis is working with fellow researchers, graduate students, and farmers to quantify the impact of this kind of landscape management. In an article published in December 2008 in the Proceedings of the National Academy of Sciences, Landis and his team note that as more land is devoted to the cultivation of corn for biofuels, agricultural landscapes become less diverse and biocontrol services—like those provided by beneficial pests—decline. For producers, this means higher losses in yield and heavier reliance on pesticides, which increases production costs.

The researchers report that developing cellulosic ethanol-processing capabilities that use a variety of feedstocks—including switchgrass, mixed prairie grasses, and woody biomass—creates the potential to diversify agricultural landscapes and more effectively support the many services provided by ecosystems.

In a study targeting Michigan’s blueberry farms, Isaacs and a graduate student found that more than 60 percent of the yield from Michigan’s $165 million blueberry crop is made possible by bees. Most of that value comes from honeybees, although native bees can be abundant in some fields.

According to Isaacs, blueberry fields with natural areas nearby, along with flowers for bees to feed on during the rest of the year, have higher native bee populations. These insects may act as “insurance” if the honeybees are unable to provide sufficient pollination. By providing the right resources around their farms, growers can make their land more suitable for native bees and reap the benefit of free pollination. Testing which native bees are most suitable as an alternative to honeybees is similar to testing the viability of alternative energy sources to power cars.

“You’ve got a resource everyone relies on, and it’s becoming more scarce,” says Isaacs. “That’s why we need to look at these alternative bees to ensure we can pollinate crops in the future.”

The benefits of pollinator research at MSU extend much further than the boundaries of Michigan. In 2008, Isaacs and Landis tracked more than 14,000 downloads of materials available on a Web site about native plants that they established to share their findings with a wider audience. Scientists from around the world are among those who have come calling, and MSU researchers are working in Tajikistan, Kyrgyzstan, and Uzbekistan to help scientists there learn how to test their native plants to determine which ones enhance pollination and pest suppression in their landscapes.

Sharing knowledge and working with other researchers—as well as crop producers and beekeepers—MSU entomologists are creating a buzz in Michigan and beyond as they advance practical solutions that will sustain pollinators and the crops that feed the world.