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Chemist helps beef up bees’ defense against destructive mites

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Massoud “Matt” Miri

A serendipitous project RIT professor Massoud “Matt” Miri began last year while on sabbatical could help protect honeybees and the pollination of commercial crops 
valued at an estimated $15 billion.

Miri, a polymer chemist, collaborated with plant physiologist Gregory Glenn and food technologist Artur Klamczynski at the U.S. Department of Agriculture Western Research Center in Albany, Calif., to enhance the honeybee’s natural defense against the Varroa destructor mite. 

“The bee project,” as Miri calls it, builds on USDA-patented applications of a natural compound to control the virus-transmitting parasite. The varroa mite hitches rides into the hive and lays eggs alongside developing bee larvae. Evidence indicates the invasive mite is associated with Colony Collapse Disorder—the unexplained disappearance of adult honeybees from commercial hives. Colony
collapse—first reported in 2006—is now linked to a confluence of parasites, pathogens, pesticides and other environmental stressors.

According to the 2012 USDA “Report on the National Stakeholders Conference on Honey Bee Health,” approximately 30 percent of managed honeybee colonies died yearly between 2007 and 2011, surpassing the historical rate of 10 to 15 percent. 

“A survey of beekeepers in Europe and the U.S. indicates that the varroa mite is the most significant cause of hive mortality,” said Glenn, project leader at the center, part of the USDA Agricultural Research Service. “The mites weaken the hive and make it susceptible to other stress factors.”

Miri and his colleagues are extending the mite-repellent properties of a compound bees secrete from their mandibles to soften and manipulate wax. The pheromone 2-
heptanone helps bees shape the wax walls
of honeycomb cells to hold larvae and stores
of honey and pollen.

“The presence of high levels of 2-heptanone in beehives has been shown to reduce the number of mites and to protect bees,” said Miri, associate professor in RIT’s School of Chemistry and Materials Science. “It may act as an anesthetic for the mites, making it easier for the bees to bite and kill them.”

In its purest form, the mite repellent is short lived and susceptible to the heat and humidity in the hive.

“The compound is a liquid that easily evaporates,” Miri said. “Simply adding
pure 2-heptanone to a beehive is inefficient because it only lasts a couple of days at
the most.”

To control an infestation, the compound must last 42 days—the equivalent of two brood cycles or life spans of a honeybee—Miri says. Glenn and his team experimented with different “carriers,” such as starch-based gels, to stretch the limits of the compound.

Miri joined the biologists trying to
harness 2-heptanone once his own project on plant-based plastics ended. Instead of
using a physical carrier, such as the gel
mentioned above, Miri chemically synthesized a liquid compound from commercially
available 2-heptanone. He also prepared
a solid derivative to compare how well they perform. 

“Under the conditions of the beehive, these compounds slowly release the
2-heptanone,” Miri said.

Miri brought the bee project back to RIT to test the chemically synthetized carriers in a simulated beehive. Miri and Tom Allston ’78, ’82 (chemistry), chemical instrumentation specialist and instructor, created the conditions within an environmental
chamber—a thick glass vessel kept at 86
degrees Fahrenheit and with controlled moisture content and airflow.

This semester, Seohyun “Felicia” Kim, a first-year chemistry major working in Miri’s lab, is measuring the amount of 2-heptanone present in the gas by injecting samples into a gas chromatogram—an instrument that separates and analyzes compounds.

“The gas chromatogram is the key
evidence that the system works—and if
it’s worthwhile,” Miri said. “If the mite
repellent is released continuously and at
a high level over the 42-day period, the
experiment will be successful.” 

Miri hopes to publish a peer-reviewed paper on the project with his USDA and RIT collaborators and to see the work field tested in defense of the honeybee.

Bee fatigue

Bee fatigue

Midwestern farmers and ranchers are planting crops and implementing conservation measures to improve honeybee health as part of a nearly $3 million initiative the U.S. Department of Agriculture launched in February. The program targets Michigan, Minnesota, North Dakota, South Dakota and Wisconsin. Beekeepers transport more than 65 percent of the country’s managed bees to the region during the summer to forage
and strengthen their hives, according to the USDA.

Honeybees are transported around the country to pollinate
a wide variety of crops.

The USDA Agricultural Research Service reports that the almond industry is especially dependent on honeybees. Approximately 60 percent—or nearly all the bees that summer in the Midwest—are needed to pollinate the almond trees in California. The demand is high for today’s 2.5 million managed honeybee colonies, which, in the 1940s, once numbered in the 5 millions.


Massoud “Matt” Miri