Bee Disease Reduced by Nature’s ‘Medicine Cabinet’

Research suggests that growing plants high in certain compounds around farm fields could create a natural “medicine cabinet” that improves the survival rates of diseased bees and pollination of crops.

By Jaime Abella Sison, DVM, FPCVFP

The researchers—composed of Leif L. Richardson, Lynn S. Adler, Anne S. Leonard, Jonathan Andicoechea, Karly H. Regan, Winston E. Anthony, Jessamyn S. Manson, and Rebecca E. Irwin—found that chemicals in floral nectar, including the alkaloids anabasine and nicotine, the iridoid glycoside catalpol, and the terpenoid thymol, significantly reduce parasite infection in bees.

The results suggest that growing plants high in these compounds around farm fields could create a natural “medicine cabinet” that improves the survival rates of diseased bees and pollination of crops. The researchers studied parasite infections in bumblebees, which like honeybees are important pollinators that are in decline around the world—a trend that threatens fruits, vegetables, and other crops that make up much of the food supply for people.

The findings appear in the journal Proceedings of the Royal Society B (February 17, 2015). Plants produce chemicals called ‘secondary metabolites’ to defend leaves against herbivores. These chemicals are also found in nectar for pollinators, but little is known about the impacts of nectar chemistry on pollinators, including bees, so they inoculated individual bumblebees with an intestinal parasite and tested effects of eight naturally occurring nectar chemicals on parasite population growth.

The results showed that consumption of these chemicals lessened the intensity of infection by up to 81 percent, which could significantly reduce the spread of parasites within and between bee colonies. “Our novel results highlight that secondary metabolites in floral nectar may play a vital role in reducing bee-parasite interactions,” says senior author Dartmouth Professor Rebecca E. Irwin. (Founded in 1769, Dartmouth College is a member of the Ivy League and consistently ranks among the world’s greatest academic institutions. It is located in Hanover, New Hampshire in the United States.)

Can Returning Crops to Their Wild States Help Feed the World?

To feed the world’s growing population—expected to reach nine billion by the year 2050—we will have to find ways to produce more food on less farmland without causing additional harm to the remaining natural habitat. A feature review, published on December 16, 2014 in the Cell Press journal Trends in Plant Science, points the way to intensifying agriculture sustainably by fixing weaknesses that have sprung up quite by accident in the process of traditional crop breeding over the course of thousands of years.

Michael G. Palmgren of the University of Copenhagen and his colleagues suggest that the most efficient way to regain those lost properties is by reinserting good genes back into our crops after isolating them from related plants or by using precision methods to repair faulty genes. “Once the genes that have been mutated unintentionally have been identified, the next step would be to reestablish wild-type properties. Rewilding would allow crop plants not only to better utilize available resources in the environment and have higher nutritional value, but also to better resist diseases, pests, and weeds,” says Palmgren.

While this back-to-nature breeding has great potential, there is one hitch, because crops restored to a more natural state in this manner would be classified, under current definitions, as genetically modified organisms (GMOs). “Studies tell us that many consumers look with some reservation upon GMO-based products, in part because they are considered alien,” says Palmgren. “Rewilded crops represent a different path, yet if branded as GM products, these may likely face considerable challenges for market penetration.”

Palmgren notes that a discussion about which products should be labeled as GMOs is necessary. “It may be useful to distinguish between the product (the plant) and the process (the breeding technology),” he says. If a crop regains the beneficial properties of a wild relative, such as disease resistance, it makes little sense to consider one plant as natural and the other as alien purely based on the method used to reach the same end result.

The bottom line for Palmgren is this: the plants we eat and depend on are not the same as those originally found in the wild, whether they’ve been genetically modified or not. “Reintroduction of some of the lost properties does not make our crops alien,” he says.

This appeared in Agriculture Monthly’s April 2015 issue.

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