PA Farm News
November 15, 2008
Colonies in collapse: What's causing massive honeybee die-offs? Part 1
This article is part one of a three-part in-depth series
By Melissa Beattie-Moss, Research Penn State Magazine
UNIVERSITY PARK — “To the bee, a flower is a fountain of life, and to the flower, a bee is a messenger of love,” wrote poet Kahlil Gibran. Whether or not love is involved in the exchange, the evolutionary dance between pollen-transporting honey bees and nectar-producing flowers is one of nature’s most extraordinary symbiotic relationships, a hundred million years in the making.
Yet what took eons to evolve can be undone in decades, as the growing roster of endangered species makes clear. While the words “endangered species” typically call to mind photogenic tigers, pandas or whales, an estimated 80 percent of all known animal species on Earth are insects, and their extinction often goes unremarked. A recent study notes that hundreds of thousands of insects could be lost in the next 50 years, and that the loss of “keystone” insect species — those on which many other species depend — could be particularly detrimental for ecosystems and people.
As the single bee species maintained by the vast majority of beekeepers in the United States and Europe, Apis mellifera, the western honeybee, is the very essence of a keystone insect. The economic worth of this crucial honeybee — which pollinates over one hundred different fruit and vegetable crops in the United States, including oranges, apples and blueberries, as well as almond trees and animal food crops like clover — has been estimated at more than $14 billion. California’s almond orchards alone require 1.5 million hives to pollinate them, and yield over $2 billion worth of almonds. In Pennsylvania, State Agriculture Secretary Dennis Wolff has made it clear that “Honeybees are critical to Pennsylvania agriculture and to our state’s economy… We can’t afford to be lax in dealing with this problem.”
Of mites and men
Prior to 1987, life was considerably less stressful for commercial beekeepers and their bees. There were the standard bee afflictions, of course — fungal infections, animal attacks on hives and most notably a contagious bacterial disease called American foulbrood, which could be successfully treated with antibiotics. Yet overall, beekeepers were able to manage these challenges and keep their losses in balance. “By comparison, beekeeping back then was a piece of cake,” recalls veteran beekeeper Dave Hackenberg of Hackenberg Apiaries in Lewisburg, Pa. “You could put the hives out and still have time to go hunting and fishing.”
By 1984, the tracheal mite — a microscopic parasite that interferes with the honeybee’s ability to breathe and curtails its ability to fly — had entered the United States. Beekeepers fought back with vegetable oil, menthol and formic acid, substances that are relatively benign to humans and bees, though sufficiently damaging to tracheal mites to suppress their populations within the hive.
It wasn’t until 1987, when the blood-sucking Varroa destructor mite was introduced into North America — probably by hopping a ride on a queen bee smuggled here from abroad by a beekeeper — that the assaults on bees became more ferocious.
By all accounts, the varroa mite — maroonish brown and about the size of a sesame seed — is primarily responsible for the mounting losses in the North American beekeeping industry over the last two decades, including catastrophic die-offs in American bees during the winters of 1995-6 and 2000-01. A 2005 study led by Penn State entomologist Diana Cox-Foster found that once the mites take hold in a hive, they suppress bee immunity. “Varroa mites in a colony open the door for many viruses and bacteria,” says Cox-Foster, noting that the pest is “widespread across the United States.”
While the pesticides approved for use against varroa mites initially kept infestations in check, within several years mites in many parts of the country had begun to develop resistance to the chemicals. Since 1987, varroa mites have wiped out between 17 and 40 percent of the total American bee population annually, a crisis that has pushed many commercial beekeepers — who make their living transporting bees to farms that pay per hive for pollination services — out of business.
A crisis on top of a crisis
“When the mites came along, we thought we had problems.” reflects Hackenberg, a lanky, gregarious man in his late 50s. “But this mess makes mites look like a Sunday school picnic.”
Hackenberg can tell you exactly when the mess started for him. “On Nov. 12, 2006, I pulled into a location in Florida where I’d left 400 hives. Three weeks before, they were fine beehives, full of bees. Within three weeks, all but 30-something hives out of 400 had flat disappeared.
“So there I was, just sitting on a gravel lot next to all those empty hives, and there’s no dead bodies on the ground, there’s no bees in the hive, and there’s no wax moths or hive beetles, nothing trying to rob out the honey, the way they usually do.”
Pausing a moment, he declares, “I’ve been trucking bees up and down the East Coast for 40 years and I’d never seen anything like this. This was different. For me, that’s the day a lot of bells started ringing.”
The telephone soon started ringing in the entomology offices at Penn State. Hackenberg’s home base in central Pennsylvania meant he was already familiar with a few bee researchers at the University and with the strength of the entomology department. Diana Cox-Foster, a soft-spoken woman who exudes an air of calm, received Hackenberg’s call, and took notes on what is now regarded as the first reported case of the mysterious bee die-off phenomenon later dubbed colony collapse disorder (CCD). Hackenberg explains that when he returned to Lewisburg, “I brought a lot of the dead stuff back to Penn State and that’s what started the whole ball rolling.”
Before long, reports began coming in across the Northeast of hives collapsing in the same characteristic way — a sudden disappearance of adult bees but no bodies in or near the hive; evidence of recent brood rearing, meaning the queen and young larvae are left behind; and an eerie absence of pests which typically pillage honey and bee bread (a mixture of honey and pollen that is the bees’ main food) from dying or abandoned hives. To date, CCD has been identified in at least 27 states and Canada, as well as in countries across Europe, particularly France, Belgium and the Netherlands, with some beekeeping operations reporting 50 to 90 percent of their colonies missing and presumed dead.
“I have never seen colonies collapse like this,” says Dennis vanEngelsdorp, State Apiarist with the Pennsylvania Department of Agriculture (PDA) and senior extension associate in entomology for Penn State. “When mites cause a colony to collapse, you’ll find a lot of mites in the remaining colonies or in the brood. We’re not seeing that here. These symptoms are very different.”
To fully grasp the mystery posed by CCD, adds vanEngelsdorp, it helps to know that a beehive — home to tens of thousands of bees — is an almost entirely female society, and honeybees are fiercely maternal. “It is extremely uncharacteristic for these bees to leave their young and never return to their hives,” he says.
Maryann Frazier, senior extension associate at Penn State, concurs. “They’re leaving behind their brood, the honey, the pollen, all their resources. For bees, this is very, very odd behavior.”
This article is part one of a three-part in-depth series
By Melissa Beattie-Moss, Research Penn State Magazine
UNIVERSITY PARK — “To the bee, a flower is a fountain of life, and to the flower, a bee is a messenger of love,” wrote poet Kahlil Gibran. Whether or not love is involved in the exchange, the evolutionary dance between pollen-transporting honey bees and nectar-producing flowers is one of nature’s most extraordinary symbiotic relationships, a hundred million years in the making.
Yet what took eons to evolve can be undone in decades, as the growing roster of endangered species makes clear. While the words “endangered species” typically call to mind photogenic tigers, pandas or whales, an estimated 80 percent of all known animal species on Earth are insects, and their extinction often goes unremarked. A recent study notes that hundreds of thousands of insects could be lost in the next 50 years, and that the loss of “keystone” insect species — those on which many other species depend — could be particularly detrimental for ecosystems and people.
As the single bee species maintained by the vast majority of beekeepers in the United States and Europe, Apis mellifera, the western honeybee, is the very essence of a keystone insect. The economic worth of this crucial honeybee — which pollinates over one hundred different fruit and vegetable crops in the United States, including oranges, apples and blueberries, as well as almond trees and animal food crops like clover — has been estimated at more than $14 billion. California’s almond orchards alone require 1.5 million hives to pollinate them, and yield over $2 billion worth of almonds. In Pennsylvania, State Agriculture Secretary Dennis Wolff has made it clear that “Honeybees are critical to Pennsylvania agriculture and to our state’s economy… We can’t afford to be lax in dealing with this problem.”
Of mites and men
Prior to 1987, life was considerably less stressful for commercial beekeepers and their bees. There were the standard bee afflictions, of course — fungal infections, animal attacks on hives and most notably a contagious bacterial disease called American foulbrood, which could be successfully treated with antibiotics. Yet overall, beekeepers were able to manage these challenges and keep their losses in balance. “By comparison, beekeeping back then was a piece of cake,” recalls veteran beekeeper Dave Hackenberg of Hackenberg Apiaries in Lewisburg, Pa. “You could put the hives out and still have time to go hunting and fishing.”
By 1984, the tracheal mite — a microscopic parasite that interferes with the honeybee’s ability to breathe and curtails its ability to fly — had entered the United States. Beekeepers fought back with vegetable oil, menthol and formic acid, substances that are relatively benign to humans and bees, though sufficiently damaging to tracheal mites to suppress their populations within the hive.
It wasn’t until 1987, when the blood-sucking Varroa destructor mite was introduced into North America — probably by hopping a ride on a queen bee smuggled here from abroad by a beekeeper — that the assaults on bees became more ferocious.
By all accounts, the varroa mite — maroonish brown and about the size of a sesame seed — is primarily responsible for the mounting losses in the North American beekeeping industry over the last two decades, including catastrophic die-offs in American bees during the winters of 1995-6 and 2000-01. A 2005 study led by Penn State entomologist Diana Cox-Foster found that once the mites take hold in a hive, they suppress bee immunity. “Varroa mites in a colony open the door for many viruses and bacteria,” says Cox-Foster, noting that the pest is “widespread across the United States.”
While the pesticides approved for use against varroa mites initially kept infestations in check, within several years mites in many parts of the country had begun to develop resistance to the chemicals. Since 1987, varroa mites have wiped out between 17 and 40 percent of the total American bee population annually, a crisis that has pushed many commercial beekeepers — who make their living transporting bees to farms that pay per hive for pollination services — out of business.
A crisis on top of a crisis
“When the mites came along, we thought we had problems.” reflects Hackenberg, a lanky, gregarious man in his late 50s. “But this mess makes mites look like a Sunday school picnic.”
Hackenberg can tell you exactly when the mess started for him. “On Nov. 12, 2006, I pulled into a location in Florida where I’d left 400 hives. Three weeks before, they were fine beehives, full of bees. Within three weeks, all but 30-something hives out of 400 had flat disappeared.
“So there I was, just sitting on a gravel lot next to all those empty hives, and there’s no dead bodies on the ground, there’s no bees in the hive, and there’s no wax moths or hive beetles, nothing trying to rob out the honey, the way they usually do.”
Pausing a moment, he declares, “I’ve been trucking bees up and down the East Coast for 40 years and I’d never seen anything like this. This was different. For me, that’s the day a lot of bells started ringing.”
The telephone soon started ringing in the entomology offices at Penn State. Hackenberg’s home base in central Pennsylvania meant he was already familiar with a few bee researchers at the University and with the strength of the entomology department. Diana Cox-Foster, a soft-spoken woman who exudes an air of calm, received Hackenberg’s call, and took notes on what is now regarded as the first reported case of the mysterious bee die-off phenomenon later dubbed colony collapse disorder (CCD). Hackenberg explains that when he returned to Lewisburg, “I brought a lot of the dead stuff back to Penn State and that’s what started the whole ball rolling.”
Before long, reports began coming in across the Northeast of hives collapsing in the same characteristic way — a sudden disappearance of adult bees but no bodies in or near the hive; evidence of recent brood rearing, meaning the queen and young larvae are left behind; and an eerie absence of pests which typically pillage honey and bee bread (a mixture of honey and pollen that is the bees’ main food) from dying or abandoned hives. To date, CCD has been identified in at least 27 states and Canada, as well as in countries across Europe, particularly France, Belgium and the Netherlands, with some beekeeping operations reporting 50 to 90 percent of their colonies missing and presumed dead.
“I have never seen colonies collapse like this,” says Dennis vanEngelsdorp, State Apiarist with the Pennsylvania Department of Agriculture (PDA) and senior extension associate in entomology for Penn State. “When mites cause a colony to collapse, you’ll find a lot of mites in the remaining colonies or in the brood. We’re not seeing that here. These symptoms are very different.”
To fully grasp the mystery posed by CCD, adds vanEngelsdorp, it helps to know that a beehive — home to tens of thousands of bees — is an almost entirely female society, and honeybees are fiercely maternal. “It is extremely uncharacteristic for these bees to leave their young and never return to their hives,” he says.
Maryann Frazier, senior extension associate at Penn State, concurs. “They’re leaving behind their brood, the honey, the pollen, all their resources. For bees, this is very, very odd behavior.”
Email editor@onlinecommunitynews.com
POSTED 081115_1000
ET
PA Farm News is a division of Online Community News
ISSN 1933-6179 © 2006-2008
No part of this website may be copied or reproduced without the written permission of the editor.
PA Farm News PO Box 243, Quarryville, PA 17566
Phone 717-333-5525