Posts Tagged: varroa mite
And it's an enemy to be reckoned with, Extension apiculturist Eric Mussen told students in the UC Davis "Biology of Parasitism" class, taught by forensic entomologist Robert Kimsey and nematologist Steve Nadler, Department of Entomology and Nematology.
Guest-lecturing at a special session held at the Harry H. Laidlaw Jr. Honey Bee Research Facility, UC Davis, Mussen talked about the varroa mite--its history, biology, damage and control methods--and then opened several hives at the apiary.
The Varroa destructor, a native of Asia, is now found in hives throughout the world except in Australia. It was first detected in the United States in 1987.
The eight-legged reddish-brown parasite, about 1–1.8 mm long and 1.5–2 mm wide, is a blood sucker that's difficult to control, Mussen said. Mites transmit viruses (there are now some 22 named RNA viruses) that can wipe out a hive. A familiar mite-transmitted disease that beekeepers see is DWV or Deformed Wing Virus. Mites are also known lowering the protein level of a bee's blood, and reducing its weight and life span.
Mussen said that mites spread from colony to colony by phoresy (animal-to-animal transport). They ride on flying drones (males) and adult worker bees (females). They also spread changing hosts on flowers.
"A mite enters a honey bee cell just before or during the time it is being capped," Mussen said. "It feeds on older larva or prepupa. Sixty hours later, the mite lays its first egg. The egg will hatch in about 24 hours."
"The number and release of offspring depend on the length of the pupal stage. The queen is pupa for 8.5 days (no mites). The worker is pupa for 12.5 days (1.3 mites) and the drone is pupa for 14.7 days (3 or 4 mites)," he said. Thus, due to the longer time required for drone development, drone pupae get the worst of it.
"When maturing, the newly emerged mites climb onto adult bees and feed by puncturing the intersegmental membranes and sucking the bee blood," Mussen related. "Often these are nurse bees that stay around the brood nest. Sometimes the hosts are drones and older foragers that are flying from the hive every day. Eventually the new mite climbs off the nurse bee onto a comb in the brood nest and enters a cell. The reproductive cycle starts and within 6 days, 44 percent of the young mites have moved into the brood cells; within 12 days, 69 percent of the mites are in the brood cells; and within 24 days, 90 percent of the mite are in the brood cells."
"If there is no brood, the mite has to feed on adult bee blood every six days or so to remain alive," Mussen said. "Mite life expectancy in summer is around 60 days; bees about 42 days. Mite life expectancy in the winter is up to 9 months; bees about six months."
Mussen also discussed how to detect mite infestations through non-chemical and chemical methods, and listed chemical treatments being used throughout the nation. Mites are developing resistance to a few chemical treatments, he pointed out. And, some of the chemical treatments not only kill the mites, but damage or kill the queen and the brood.
Beekeepers who try to go organic, figuring that "if the bees can't make it on their own--if they're not fit--let them die" are really doing a disservice to neighboring beekeepers, Mussen said. The mite will overrun a colony and then infest other colonies.
Public Enemy No. 1--definitely a force to be reckoned with.
Extension apiculturist Eric Mussen (second from left) talks to a UC Davis class in the apiary of the Harry H. Laidlaw Jr. Honey Bee Research Facility. Third from left is forensic entomologist Robert Kimsey, one of the two class instructors.(Photo by Kathy Keatley Garvey)
Extension apiculturist Eric Mussen shows a frame to the students. (Photo by Kathy Keatley Garvey)
Varroa mites are reddish brown. (Photo by Kathy Keatley Garvey)
Extension apiculturist Eric Mussen reaches for a smoker as a bee (far left) buzzes off. (Photo by Kathy Keatley Garvey)
If you want to take photos of honey bees in flight, do so early in the morning. They don't move as fast and the lighting is to die for.
This morning we stepped out in our yard, steaming coffee in hand, and watched the honey bees foraging among the lavender blossoms. Against the backdrop of red pomegranate blossoms and spring green leaves, they crawled up and down the lavender and then took off for the next blossom.
So smoothly. So effortlessly. So tirelessly.
You don't always have to stop the action with a flash. We took this with a Nikon D700 with a 105mm macro lens. No flash. We set the aperture (f-stop) at 8, the shutter speed at 1/800th of a second, and the ISO at 800.
The blurring of the wings added to the feeling of speed.
Indeed, the honey bees seem a little more frantic now as they rush to bring back nectar, pollen, propolis and water to the hive. With the queen bee laying about 2000 eggs a day now, everyone has to pitch in.
Just call this "The Lavender Blossom Special."
Honey bee in flight, heading toward a lavender blossom. Note the varroa mite on her head.(Photo by Kathy Keatley Garvey)
There's joy on the horizon for beekeepers battling that pesky Varroa mite.
They may soon have a "fool-proof" method to silence the parasite, considered the honey bee's worst enemy.
A research team led by Alan Bowman of the University of Aberdeen, United Kingdom, recently developed a genetic "knock-out" technique that could cause the blood-sucker to self-destruct.
The research could lead to an anti-Varroa medicine placed inside the hive, according to a BBC News article.
So common is the Varroa mite in a typical hive that it's considered the fourth member of the colony. Think queen bee, worker bees, drones, and Varroa mites. (Source: The newly published Storey's Guide to Keeping Honey Bees by Malcolm Sanford and the late Richard Bonney)
The Varroa mite, first detected in the United States in 1987, is a killer. It transmits viruses, suppresses the immune system, weakens colonies, and if left untreated, can decimate an entire colony. BBC science reporter Victoria Gill captured its destructiveness well when she quoted Giles Budge of the National Bee Unit, Yorkshire.
The human equivalent of varroa mite, Budge told her, would be "an organism on your back that's about the size of a dinner plate, which creates a hole through which it can feed and through which its family can feed."
The free-lunch bunch has met its match.
Varroa Mite on Pupa
Varroa mite on adult bee
Is coconut oil effective in treating varroa mites, those nasty little mites that plague our honey bees?
The facts aren't in, and research is ongoing.
Extension apiculturist Eric Mussen of the UC Davis Department of Entomology faculty, will discuss his research, “Coconut Oil - Varroa Treatment or Food Ingredient?” at the California State Beekeepers' Association (CSBA) convention, set Nov. 16-17 in the Embassy Suites, San Luis Obipso.
He'll address the crowd on Tuesday, Nov. 16. (To read more about honey bees, check out his newsletter, from the UC Apiaries, and his Bee Briefs on his website.
Bee breeder-geneticist Susan Cobey will address the conference on "Honey Bee Stock Improvement: Challenges and Options" on Thursday, Nov. 18.
In addition, she'll speak Nov. 16 at Cal Poly's Horticulture and Crop Science Department on “Mating is Risky Business and the Benefits Of Being Promiscuous." That talk is part of the Dow AgroSciences Seminar Series: “New Advancements in Biotechnology and Sustainability of Crop Science."
The CSBA is headed by Roger Everett of Porterville, who is also a member of the California State Apiary Board.
CSBA’s purpose is to “educate the public about the beneficial aspects of honey bees, advance research beneficial to beekeeping practices, provide a forum for cooperation among beekeepers and to support the economic and political viability of the beekeeping industry.”
Checking the hives
One way that beekeepers monitor their hives for mite infestation is "the sugar shake."
Basically, this involves a quart canning jar equipped with a mesh screen and a lid; and powdered sugar. Beekeepers brush bees from brood comb into a plastic tub or container--being careful, of course, not to brush the queen bee in there, too. They scoop a half of a cup of bees into the jar, add a couple tablespoons of powdered sugar, and then it's time to do "the sugar shake."
They shake the jar vigorously, invert it, and the mites come tumbling out through the mesh screen.
The result: sugar-coated bees and suffocated mites. And all's right with the world. Or "white" with the world.
Beekeepers then count the mites to determine the level of mite infestation and the kind of treatment, if any, that's needed.
Meanwhile, the bees return to their hive where their sisters quickly groom them ("Hey, what happened to you?").
The powdered sugar is harmless. A few minutes later, routine hive activity resumes as if The Great White Shake never happened.
For a brief moment in time, however, the test bees are the insect equivalent of Snow White.
Or the food equivalent of powdered sugar doughnuts or Mexican wedding cookies.