What’s Killing American Honey Bees? by Benjamin P. Oldroyd, an Australian entomologist, is without a doubt the best summary of the current state of play on Colony Collapse Disorder. I know I’m biased, being — gasp — a scientist, but Oldroyd’s paper is the bees’ knees. It has hypotheses (wot, no mobile phones?), facts, and interpretations. And one rather interesting conclusion. I’ll let Oldroyd explain:
Remarkably, honey bees maintain the temperature of their brood nest within ± 0.5 °C of 34.5 °C, despite major fluctuations in ambient temperature. If the brood is incubated a little outside this range, the resulting adults are normal physically, but show deficiencies in learning and memory. Workers reared at suboptimal temperatures tend to get lost in the field, and can’t perform communication dances effectively. Although entirely a hypothesis, I suspect that if colonies were unable to maintain optimal brood nest temperatures, CCD-like symptoms would be apparent.
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I suggest that another possible cause of CCD might simply be inadequate incubation of the brood. Thus any factor—infections, chronic exposure to insecticides, inadequate nutrition, migration in adult population, and inadequate regulation of brood temperature might cause CCD-like symptoms.
My hypothesis could be easily tested by removing brood from several colonies and incubating some of it at optimal temperature and some at suboptimal temperature. The brood would then be used to constitute new colonies in which some colonies comprise workers raised at low temperature and some comprise workers raised at optimal temperature. I predict that the colonies comprising workers reared at suboptimal temperature will show signs of CCD. Moreover, I would not be surprised if they showed higher levels of stress-related viral infections. These effects could act synergistically—more virus leads to shorter-lived, less efficient workers, that in turn leads to suboptimal temperature regulation, and more short-lived bees.
See, kids, that’s the way science is done. But really, go read the article. And if there’s anything in it you honestly don’t follow, ask.
Great article! Thanks for bringing it forward.
Perhaps one way to provide more support for the sub-optimal temperature hypothesis would be to plot the geographic location of CCD occurence against the early spring temperatures for that location, or at least the temperatures over the period during which the missing workers would have been brood. A negative correlation between lower temperatures and CCD would seem consistent with Oldroyd’s hypothesis.
Excellent idea. Maybe someone’s already doing that?