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Scientists "Sketch" Genetic Profile of Honeybee Attacker

Mapping a key genetic component of the varroa mite is in the works to expedite studies aimed at monitoring the tiny, bloodsucking parasite and minimizing its harm to honey bees.

Agricultural Research Service scientists are mapping genes in mitochondria. In the cells of varroa mites and other organisms, including honey bees and human beings, mitochondria function as tiny power plants that fuel the cells’ metabolic machinery. Of specific interest to ARS entomologist Jay Evans is variation in the genes encoded within the DNA (deoxyribonucleic acid) of the varroa’s mitochondria. Compared to the mite’s entire genome, mitochondrial DNA (mtDNA) contains fewer genes--and these genes are easier to identify.

Using standard molecular procedures, including polymerase chain reaction, or PCR, Evans and coworkers at the ARS Bee Research Laboratory in Beltsville, Md., have decoded the sequence for most of the parasite’s mtDNA.

Once finished, they’ll look for genetic markers associated with particular traits of interest, such as virulence (destructiveness in honey bee hives) and pesticide resistance.

Also of interest is using the markers to help resolve taxonomic uncertainties surrounding the mite’s identity and origins as a honey bee pest. And the marker technology should help identify any new, accidental introductions of the varroa mite. Since arriving in Florida in the 1980s, the mite has spread across the nation to become a top pest of both feral and managed honey bees, whose crop-pollinating activity is considered a $14-billion asset to agriculture.

About a millimeter long, the reddish-brown varroa mite can kill or weaken adult and larval bees by sucking their blood and can also expose bees to diseases, according to Evans. Severe attacks that go unchecked can easily destroy an entire hive, he adds.

A longer story about Evans’ research appears in the June issue of Agricultural Research magazine.

ARS is the U.S. Department of Agriculture’s chief scientific research agency.