Mites bite bees; bees bite back
The bugs transmit viruses that kill bee colonies
Out in the unmowed field near the big white barn behind the Sisters of St. Joseph motherhouse in Baden, Sister Lyn Szymkiewicz in full beekeeper gear has just lifted the top off a wooden box hive and begun a routine inspection of its busy, buzzing inhabitants.
She moves deliberately, standing in back or to the side of the file cabinet-like hives, never in the front “flyway” routes that the bees use to travel to the hives’ entrances. From each hive, she pulls out several “frames,” the thin, rectangular plastic mesh sheets with wood borders where the honey bees build their nectar-filled wax combs, and on which the queen lays her eggs. Most of the frames are covered with bees.
Peering through the fine netting of her veil, she checks to see if the bees look healthy, if they need food, if the queen is in the hive, if eggs have been laid in open cells and how much of the honeycombs have been filed and capped. And she checks for mites. Specifically, the varroa mite, a red parasite about the size of a deer tick, that bites into honey bee larvae, pupae and adult drones and worker bees, transmitting viruses that have, can and do kill honey bee colonies nationwide.
“Last year was the first year I lost a colony and I lost three,” said Sister Szymkiewicz, who started keeping bees at the Beaver County site 11 years ago and has 17 hives this spring. “And last year the mite counts were the highest I’ve ever seen.”
No. 1 enemy
She didn’t find mites in the hives she checked last week. But she was not alone in losing colonies this winter to mites.
The Pennsylvania State Beekeepers Association’s 2017 Winter Loss Survey shows that the 831 beekeepers who responded had 5,443 colonies alive in November 2016 but just 2,593 colonies alive in April of this year, a 52 percent colony loss.
Of the colonies lost, beekeepers said 225 were due to mites. More than 500 other colonies were lost to “unknown” or “other” causes that also could have been related to mites.
“Absolutely mites may have
bees exhibited that chewing behavior,” Mr. Wells said. “But through a breeding program that uses bee stock from Europe where varroa was introduced 15 years earlier than it was in the U.S., that behavior was boosted to 50 percent and then 75 to 80 percent. It seems the bees are evolving.”
He said the chewing bees were dubbed “Purdue anklebiters,” even though mites don’t have ankles, and the name attracted muchneeded attention to the problem among beekeepers.
“They’re chewing and we should be helping. We should be educating beekeepers, get everyone to participate in educated pest management and treat for mites within a coordinated timeframe,” Mr. Wells said. “In northwestern Ohio we’re seeing a lot of chewing behavior and we are at the tipping point. We are training beekeepers, and have momentum. We’re working with researchers and keepers to build the anklebiters to a critical mass.”
Plant pollinators
Related research is underway at Penn State University, where Margarita Lopez-Uribe was recently hired to lead a project aimed at identifying, finding and genetically analyzing feral or wild bees that have stronger immune systems.
“We just collected our samples, 18 feral colonies from 10 sites and we’ve paired them with managed bees,” Ms. Lopez-Uribe said. “The idea is to use the stronger genetic immunity from feral bees to improve honey bee health.”
Eventually, she said, the program will produce genetic stock that can be used by local queen bee breeders to produce mite resistant bees.
The heavy research focus on bees reflects their importance as plant pollinators. The U.S. Department of Agriculture estimates that 80 percent of the pollination for many fruit and vegetable crops consumed by humans is accomplished by honey bees. The bees also produce about $150 million worth of honey in the U.S. annually.
“Honey is an agricultural product and colony losses can cause big commercial businesses to lose millions of dollars,” said Sister Szymkiewicz, who sells the approximately 1,000 pounds of honey her bees produce annually to help support the Sisters of St. Joseph’s various ministries.
“Can you imagine losing 40 or 50 percent of the beef herd before going to market?”
But there is reason for some optimism. While over the last decade about 30 percent of bee colonies nationwide were lost, a survey of U.S. beekeepers released Thursday by the Bee Informed Partnership found just 21 percent of colonies nationwide were lost last winter, the lowest percentage loss in nearly a decade but still higher than desired.
According to the not-forprofit Partnership, a reduction in varroa mites, attributable to a new miticide, was likely the main cause for the improvement.
“The mites remain a big problem for us,” Ms. Lopez-Uribe said. “But it remains a puzzle why Pennsylvania consistently registers among the highest colony losses on an annual basis.”
John Yakim, president of the Beaver Valley Area Beekeepers Association, said the website of the Bee Informed Partnership (https://beeinformed.org/), a nationwide collaboration of research labs, university agricultural programs and scientists is a good tool for beekeepers looking for information about honey bee decline and how to keep healthier bees.