Author: Jeremy Cherfas

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The best bee paper ever … for now

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.

… snip …

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.

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Ecotourism investigated

From id21, a report that questions some of the assumptions about ecotourism, and asks whether it really is an innovative conservation and development strategy or merely a celebration, by those who can afford it, of poverty?

Ecotourism projects tell communities they can generate revenue by protecting biodiversity, but also that they should never hope to achieve much beyond this role. This ties the development prospects of rural communities to local, natural limits in a way that is completely alien to economic development in richer societies.

Given that the author, Jim Butcher, takes a pretty dim view of the whole scene, I suppose I should be glad that he does not seem to recognize agricultural ecotourism at all. But there are strong suggestions that this can help communities not only to gain an income but also to preserve their traditional knowledge at the same time as making the modern development steps needed to connect to the wider world. (There is a method for commenting on the id21 site, but it seems awfully cumbersome, and I can’t actually see whether anyone has commented on Butcher’s piece.)

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Images of Diversity

Grain GRAIN, an NGO, has published a photo essay that shows a mobile seed festival that took place from 14 January to 13 February 2007 in Andhra Pradesh, India. While GRAIN’s web technology is a lot cruder than Time magazine‘s, and the content is occasionally a little harder to swallow then even the Mexican family‘s fondness for a certain fizzy carbonated drink, it does offer a useful insight into seeds and agricultural biodiversity and what they mean to one local community.

So, GRAIN, why not spice things up a little and enter your photos in our competition? And the rest of you, why not take inspiration from GRAIN, or indeed Time, and document an aspect of agricultural biodiversity? You know it makes sense.

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Making sure nutrition is maintained

Truffling through the special issue of African Journal of Food Agriculture Nutrition and Development about African Leafy Vegetables, one paper caught my eye: Changes in Beta-Carotene, Ascorbic Acid and Sensory Properties in Fermented, Solar-Dried and Stored Cowpea Leaf Vegetables, by Muchoki, Imungi and Lamuka. But only because a couple of days ago a different story — Sunlight Reduces the Value of Moringa Leaves — had done the same. Both tell the same basic story, that even all-powerful traditional leafy vegetables need care in their preparation if they are to deliver the nutritional benefits they are capable of.

Unfortunately I have been unable to find a copy of Ritah Namutebi’s poster on Moringa oleifera, so I have only the newspaper report to go on. Namutebi picked Moringa leaves in the morning, at midday and in the evening and dried them in direct sunlight or in the shade. Those dried in direct sunlight lost 35-60% of their vitamin A, while those dried in shade lost less, 11-15%. ((Actually there’s a conflict in the report. One paragraph gives the figures I have quoted. The following one says that shade drying loses up to 25%, rather than 15%)) There is no information on the effect of time of picking; presumably it made no difference.

The cowpea paper is a whole heap more detailed, with three different treatment methods and six different storage regimes. Bottom line:

  • Fresh leaves contain roughly six times more ascorbic acid (vitamin C) than dried leaves, but the type of drying makes no difference.
  • Drying makes no difference to the amount of beta-carotene, a precursor of vitamin A.
  • During storage, both the container (polyethylene bags vs Kraft paper) and the temperature affect the levels of vitamins in a manner that depends on how the leaves were initially prepared.
  • At each temperature, polyethylene preserved the vitamins better than Kraft paper.

There’s more, I’m sure, to be gained from this work, but the crucial point is that it is as important to devise appropriate methods of preserving neglected and underutilized species as it is to promote their use in the first place.