Just recently Colony Collapse Disorder was back in the news. Swiss scientists conducted an experiment to look into claims (even) cell phones may have something to do with CCD. They concluded bees don´t like the buzz.

Most specialists however agree CCD is likely caused by a culmination of factors, including pesticides – and microbial pests. And we´ve dug up some further research that seems to support that idea.

In early 2010 a group of four French biologists suggested dietary changes could affect honey bees’ immune system – and this in turn could be (one more) key to explaining the rise of parasites like varroa destructor and other plagues, including viruses and fungi – that are associated with sudden die-offs of bee colonies.

Wild honey is not just sugar

Bees are like humans. If you feed them sucrose solution (or soft drinks) they attain just one macronutrient (sugar), therefore develop other nutritional deficiencies and become unhealthy. For proper immune function for instance sufficient protein consumption is required. For bees this means they have to find (combinations of) flowers with nectars that contain small protein chains, or amino acids, the buildings blocks for protein.

The biologists are especially interested in the level of bee immunocompetence, as this influences the production of glucose oxidase (GOX). Bees use this chemical to sterilise their hyves and the honey food stores in it. As GOX declines, the colonies become more susceptible to invasion by microbes and other pests – that are so often found in CCD-affected hyves.

Bees like a mixed bouquet

The French in their research – that was published in Biology Letters – find it is not the net protein content, but the ‘polyfloral’ protein content that influences immunity and GOX production. That means ‘eating a varied diet,’ by collecting small amounts of protein from various different flowering plants could be important for the bee’s health and their ability to protect themselves from pests:

“In particular, polyfloral diets induced higher GOX activity compared with monofloral diets, including protein-richer diets. These results suggest a link between protein nutrition and immunity in honeybees and underscore the critical role of resource availability on pollinator health.”

Biodiversity decline

Although ecologists warn the world is in a clear biodiversity crisis – as our planet is sliding into a mass extinction event after [depending on definition of the word ‘mass’] 55.8[PETM]-65.5[K-T] million years of green, lush, fertile ´peace and quiet´ (ignoring the occasional hiccups of ice ages and interglacials) – it may be too soon to link that decline to CCD.

That is because there is a much more logical explanation at hand to see why bees would be turning to a fast-food diet: intensive agriculture – mono agriculture, for instance fields of onions, soybeans, cabbage, potatoes or cucumber [to emphasize the importance of bees for the human food chain – yes, these plants do all (to some extent) require pollination] that may, in modern times, stretch for miles on end.

Urban bees do better

This would also support claims from beekeepers in several European countries that bees would be doing better in urban areas than on the countryside, as they would benefit from flower diversity in gardens and parks – and have less contact with monoculture farmland.

So if you want to help our little pollinating friends a bit, you know what to do. Remove those pebblestones to start with.

CCD story continues

Again, as with the cell phones, the pests and the imidacloprid, we have to acknowledge with a decline in flower diversity we are likely only looking at one of the causes of CCD (in western countries). And it is still quite possible biologists have not yet attained all the required pieces to solve the puzzle.
We’ll keep you up to date.

© Rolf Schuttenhelm | www.bitsofscience.org