Last week I began to explore some of the threats challenging the honey bee. In addition to parasites the bees are also suffering from:
Farming habits in England have changed dramatically in the last century. We now have fewer ancient hedgerows, bigger fields and more mechanised practices. This has resulted in large areas of land growing human and animal food crops which do not produce the nectar-rich flowers needed by bees. Field margins used to be full of wildflowers but modern farming has also reduced this food source. The land might appear fertile to us, but to hungry bees it is like a desert. It seems strange, but bees can now find more food in cities and suburbs than in the countryside.
The last few years have seen some very cold and wet weather in Britain. It is difficult for bees to leave the hive to forage on wet days because the rain makes flight difficult and they are at risk of getting too cold to fly. Also, if a bee’s temperature drops below 8oC it will die. However if the colony stays inside for long periods of time it affects the temperature and humidity of the hive and can increase the risk of infection from parasites. It also means that the bees have to eat from their stores and are not able to collect more nectar to replace what has been eaten.
The best way to protect a hive and to ensure its survival through bad weather is to make sure that the colony is as strong and healthy as possible. Hives should also be kept up off the ground to allow air circulation and prevent damp, and they should be placed somewhere out of the wind.
Pesticides and Fungicides
In a recent report, published in the journal PLOS ONE, scientists from the University of Maryland and the US Department of Agriculture “have identified a witch’s brew of pesticides and fungicides contaminating pollen that bees collect to feed their hives.”
The researchers collected pollen from certain plants on the east coast of America and fed it to some bees, finding that it lowered their resistance to a parasite that can cause the collapse of a colony.
” The discovery means that fungicides, thought harmless to bees, are actually a significant part of Colony Collapse Disorder. And that likely means farmers need a whole new set of regulations about how to use fungicides.”
(treehugger article: ‘Scientists discover another cause of bee deaths, and it’s really bad news’, July 26, 2013)
It was already known that neonicotinoids (a relatively new type of insecticide, used in the last 20 years to control a variety of pests, especially sap-feeding insects, such as aphids on cereals, and root-feeding grubs) have been responsible for huge numbers of bees dying, but this new study revealed that many more chemicals are involved resulting in a much more complex challenge.
Spraying practices also need to be reviewed as it was discovered that bees forage “not from crops, but almost exclusively from weeds and wildflowers, which means bees are more widely exposed to pesticides than thought.”
These chemicals were thought to be safe, and of themselves they might not be lethal to the bees, but it appears that they affect the immune system making them more susceptible to attacks by parasites such as the Varroa mite and Nosema.
It is not economically practical, however, to simply stop spraying crops with these pesticides and so various groups have been looking into alternative ways of supporting bees and other pollinators. I’ll be looking at these in Part 5 next week.
(This is an extract from my article which you can read in full here)