In a paper published in Environmental Microbiology, Professor Elke Genersch and colleagues in Berlin announce what’s been reported as a “major breakthrough” in honeybee pathology. A new understanding of how the bringing bee researchers one step closer to finding a way to prevent the spread of American Foulbrood disease (AFB), the only infectious disease which can kill entire colonies of bees.

American foulbrood (AFB) is a bacterial disease of honeybee larvae caused by the spore-forming bacterium Paenibacillus larvae. Although AFB and its aetiological agent are described now for more than a century, the general and molecular pathogenesis of this notifiable disease is poorly understood.

The accepted view was that the bacteria germinate preferentially at either end of the gut of honey bee larvae, then make holes in the gut wall and enter the larval organ cavity. The organ cavity was believed to be the primary place where the bacteria grew and multiplied.

What the German research team learned is that the bacteria act to cause ABF infection in a completely different way than originally thought.

The disease-causing bacteria colonize the larval midgut and do most of their multiplying there — living from the food ingested by the honey bee larvae — until eventually the gut contains nothing but these pathogens. It is not until this point in the process that the bacteria ‘burst’ out of the gut into the organ cavity, killing the larvae.

“Now that we fully understand the way in which this disease works, we can start to look at ways of preventing the spread of infection” said Professor Genersch.

See also:
• Bees Disease: One Step Closer To A Cure
  ScienceDaily: 4 May 2008
• Fluorescence in situ hybridization (FISH) analysis of the interactions between honeybee larvae and Paenibacillus larvae, the causative agent of American foulbrood of honeybees (Apis mellifera) (abstract).
  Dominique Yue, Marcel Nordhoff, Lothar H Wieler, Elke Genersch
  Institute for Bee Research, Friedrich-Engels-Str. 32, 16540 Hohen Neuendorf, Germany.

Thanks to CBA member Sterling Clark for spotting this item in Catch the Buzz.

Scientists at HortResearch have successfully bred honeybees that are capable of fighting back against varroa mites by suppressing the reproduction of the pests. This welcome news for beekeepers was announced recently by the science company, a Crown Research Institute which is wholly owned by the New Zealand government:

Scientists breed varroa ‘resistant’ bees

Auckland, New Zealand, 16 December 2007 — A sustainable and cost-effective tool to control the varroa mite may soon be available to New Zealand beekeepers thanks to the efforts of scientists at the Crown Research Institute, HortResearch.

Scientists at HortResearch have successfully bred honeybees that fight back against varroa — by suppressing mite reproduction.

Since its arrival in New Zealand seven years ago varroa has become the number one enemy of bees and beekeepers across much of the country. Able to reproduce and spread rapidly, the mite lays its eggs inside the brood cells of a beehive, where the mites develop to maturity by feeding on bee larvae.

Uncontrolled, varroa will usually ‘kill’ a bee colony within a year — an expensive loss to beekeepers as well as a major threat to honey producers and New Zealand’s billion dollar fruit export industry, which relies on bees for pollination.

Varroa is currently controlled mostly through the use of chemical miticides — at an annual cost to industry of over $1.5 million. While such treatments are generally effective, their use is not sustainable says HortResearch honeybee scientist Dr Mark Goodwin.

“Overseas, varroa has quickly built up resistance to these miticides, resulting in large hive losses. In addition, while perfectly safe if used correctly, beekeepers and growers would prefer not to have these chemicals in our natural environment.”

With funding from the Sustainable Farming Fund, the National Beekeepers Association, individual beekeepers, and the kiwifruit industry through ZESPRI Limited, Dr Goodwin and his team have been searching for more sustainable ways of keeping varroa in check.

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New Brunswick poet Bliss Carman (1861-1929) wrote his ode to the honey bee collaboratively with the American poet Richard Hovey, and it appeared in their book Songs From Vagabondia, published in 1894.

It’s just a shame that Carman didn’t know more about Apis mellifera.

The poet made the common mistake — perpetuated in works from the time of the ancient Greeks right through to Seinfeld’s newly released animated film, Bee Movie — of thinking that the male bee, the drone, “works like a Trojan hero;
Then loafs all winter upon his hoard…”

In actual fact — the premise of Hollywood film plots notwithstanding — the male bee serves no practical purpose in the colony beyond queen-mating. When the weather turns cold, and the drones are no longer needed, they are firmly turned out of the hive so the colony’s food resources can be used to sustain the queen and worker bees through the winter.

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The CBC Radio program As It Happens posted a story on 22 October 2007 about the value to a colony of queen bees mating with multiple drones — it’s all about genetic diversity.

This story gives new meaning to the expression “busy as a bee.” New research shows that queen bees ensure they remain in charge of the hive by sleeping with as many male bees as possible. Well, it worked for Catherine the Great!

2007-10-22 As It Happens (MP3 audio fle)

In this entertaining audio podcast, Christina Grozinger, Assistant Professor of Entomology at North Carolina State University, tells of studying the differences in pheremones of queens who mated with many males, as opposed to those who mated with only one. (There seems to be a higher quality of pheremones in the multiple-mated queens, so the worker bees are more attracted to a multiple-mated queen and may be less likely to try to replace her.) Along the way, she gives a basic “birds and bees” chat explaining how honeybees mate and the role of the queen bee within the colony.

Research shows that when worker bees are half-sisters, rather than sisters, the colony is healthier. If the bees are challenged with a disease, for example, they’re more likely to be able to fight off that disease if the queen bee has mated with many different males and therefore there is more genetic diversity in the colony.

See also:

CBC Podcasts - Frequently Asked Questions (F.A.Q.)
Alternate sources: 2007-10-22 As It Happens CBC media feed / direct mp3 file

Christina M. Grozinger: Research Interests

At 10 minutes in length, this video provides a good introduction to the lifecycle of honey bees. It is suitable for school science classes, for home-schooling activities, and even for new beekeepers who’d just like to see some excellent footage of what they can expect to see happening in the hive through the beekeeping season.

The life cycle of a honey bee is presented as an example of complete metamorphosis, the development of an insect from egg to larva, then pupa, then adult. Moths, butterflies and wasps also develop with complete metamorphosis. Some aspects of beekeeping are also discussed.

Metamorphosis is one of a series of science videos from Hila Science Camp, Ontario, Canada. Preview versions of these videos are made available for viewing online through Google Video and Youtube without charge, or for purchase as a higher quality download at http://hilaroad.com/video/.