Montana State University

The buzz about Colony Collapse Disorder

May 7, 2009 -- Melynda Harrison, MSU News


MSU graduate student Joanna Gress inspects the condition of a bee she will use to help research a fungus that may play a role in Colony Collapse Disorder. MSU photo by Kelly Gorham   High-Res Available

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Montana State University graduate student Joanna Gress drove from Polson to Bozeman with 50,000 honeybees in her car at the end of April.

"It's was a four hour drive with a lot of bees, but it's what I do for science," said the plant sciences doctoral student with a laugh.

Gress brought the bees to MSU to study a possible cause of, and develop a potential management strategy for, Colony Collapse Disorder (CCD). The bees were obtained with assistance from University of Montana professor Jerry Bromenshenk and his colleagues. Bromenshenk is one of the state's leading bee researchers and has been at the forefront of Montana research into possible causes of CCD.

The main symptom of CCD is a rapidly depopulated beehive. The queen and immature bees (brood) remain, and there are no dead bees in the hive -- adults have simply disappeared. Often there is still honey. According to the U.S. Department of Agriculture, some beekeepers began reporting losses of 30 percent to 90 percent of their hives in late 2006 to CCD.

"Overnight, the bees are just gone and you don't know what happened," said Gress.

The bees may have been infected by single-celled, spore-producing fungus called Nosema ceranae. Nosema ceranae is one of many possible causes of CCD that bee researchers are looking into.

Nosema ceranae was first found in Asian honeybees. It then jumped to European honeybees and now can be found worldwide. It has been in the United States since at least 1995, and ongoing research is attempting to determine exactly when it arrived.

Nosema spores have a tough resistant wall protecting them from conditions in the host and in the environment. Conditions in the bees' intestines trigger the explosive release of spores and their contents into the cells of the host bee. The Nosema nuclei divide repeatedly inside the infected bee, producing organisms. Some of those organisms mature into spores, completing the lifecycle.

There is an antibiotic that kills the fungus in its active, reproducing state, but there is no known method of killing its spores.

This is a problem for beekeepers. As they share combs among hives and use the same equipment to clean multiple hives they can inadvertently spread the spores, infecting other colonies.

According to the USDA, one in three mouthfuls of the American diet directly or indirectly benefits from honeybee pollination. Bee pollination is responsible for $15 billion in added crop value, particularly for specialty crops.

As a doctoral student, Gress rotated through three MSU researcher's laboratories to gain a variety of experiences. In one rotation she participated in fungal biologist Robert Cramer's ongoing research on Nosema ceranae. Gress tested different compounds beekeepers could use to kill the Nosema ceranae spores and found that a 10 percent bleach solution worked the best. Beekeepers may be able to use it to clean their hives and equipment.

"The great thing is that it is cheap and readily available," said Gress. "I don't know if you can totally get rid of (the fungus). But, I think we can reduce it so that it's not interfering with honey production."

The bees Gress picked up in Polson with help from Bromenshenk's group will be used for another CCD project. The three colonies will be kept on the MSU campus at the Montana Agricultural Experiment Station. Cramer's lab technician, Peggy Lehmann, and Gress will siphon bees off the healthy hives to infect with two species of fungi in Cramer's lab: Nosema ceranae and Nosema apis.

Nosema ceranae has replaced a related species of fungus-- Nosema apis --that causes bee dysentery, but less death.

Gress aims to determine whether Nosema ceranae is involved in CCD in the United States.

"We are not sure what causes CCD in the U.S., but it is probably multi-factored," said Gress. "It's like a perfect storm of high levels of infection by the varroa mite (a parasite that feeds on bee blood and transmits bee viruses), poor nutrition due to pollinating crops with low nutritional value, and pesticide use."

Using microarray analysis, Lehmann and Gress will look at the gene expression of infected bees to see what genes are different between the bees infected with the two different Nosema species versus uninfected bees. Lehmann hopes to determine if the bees' immune systems respond differently to the two fungi.

Gress hopes the analysis will lead to clues that explain why Nosema ceranae is more virulent than Nosema apis. It may be that the fungus puts an increased stress on the bees, or it may be that it is more lethal because the bees cannot muster a strong immune response to it.

"If the latter is the case then maybe we want to try and breed for greater resistance to Nosema ceranae," said Gress. "It's an important question to figure out in order to help beekeepers come up with a management strategy."

It was a lecture by entomologist (and now Gress' advisor) Kevin Wanner that drew her to bee research. She became more interested after speaking with Cramer, who is working on Nosema ceranae.

"Joanna rotated through our laboratory to gain some experience working with honeybees and Nosema ceranae," Cramer recalled. "Joanna is very enthusiastic about honeybees and she has the drive and passion to make this a successful endeavor."

"I've always thought CCD was interesting and this is a new field at MSU," Gress said. "We have done some bee research here, but not a lot, so it is exciting to spearhead this project."

Gress purchased two jars of sting stopper and admitted to being a little nervous about driving a car full of bees, but she felt it was worth it to move on the next step of her research.

"I like big-picture projects that have a real world application," said Gress. "I'm going into this really excited."