Bees are vital for pollination of the flowering plants that provide at least one-third of the human diet. The value of bees and other pollinating insects to agriculture in 1975, according to Science Daily, was an estimated 153 billion Euros, or over 200 billion U.S. dollars. However, beekeepers are finding that many of their hives are dying mysteriously, a situation which is termed colony collapse disorder (CCD). Bee populations are in crisis, and it is feared that honey bees are vanishing.
Researchers have been attempting to identify the causes of CCD but have failed to identify one specific cause, and there may be many interacting factors involved. According to a PBS video, bees and other pollinating insects are threatened by industrialization, urbanization and the disruption of habitats. Other possible factors include the effects of pesticides, which can impact the food-seeking behavior of bees by interfering with their sense of smell.
In addition, bees have been dying in record numbers from infections by mites, viruses, fungi and parasites. One theory is that, when attacked by a combination of infections, bees lose their ability to navigate and cannot find their way from the hive to their food source and back again. It has also been suggested that bees have lost their ability fight off disease because the selective breeding of commercial bees has reduced genetic diversity. However, this does not explain why wild pollinating insects are also disappearing.
Another proposed cause of immune deficiency in bees is malnutrition, possibly resulting from climate change or drought. The practice of feeding high-fructose corn syrup to bees in the winter has also been blamed, but beekeepers who do not feed high-fructose corn syrup to their hives also experience CCD. A more plausible explanation for bee malnutrition is a lack of pollen variety. A 2010 study found that bees which obtained pollen from a variety of different plant species appeared to have healthier immune systems than those taking pollen from a single species. However, current beekeeping practices such as using bees to pollinate a single orchard crop in the summer and feeding them artificial pollen substitutes such as high-fructose corn syrup over the winter may lead to a compromised immune system.
Bees may also be finding it harder to locate food. Worker bees navigate by the sun and perform a circular dance at the entrance to the hive which relates the location of the pollen to the direction of the sun. However, on cloudy days they navigate by and relate their dance to magnetic directions, and it has been found their dance may be disrupted by anomalies in the Earth’s magnetic field. It is therefore suspected that electromagnetic fields emitted by solar power satellites, microwave receiving stations and cell phones may disrupt the bees’ navigational ability, but little research has been done. A review of research on the effects of electromagnetic radiation published by the Indian government in 2011 found only seven studies on bees, with only one which found a possible link to CCD.
With bee populations becoming more prone to disease, beekeepers have been using more fungicides and miticides, and it is believed that two common miticides, coumaphos and fluvalinate, may further damage the bee’s immune system, leaving it more susceptible to viruses.
The impact of genetically modified crops is also a concern. Some GM crops contain biopesticides which are toxic to butterflies, moths and beetles, and which may have an adverse effect on the learning and feeding behavior of bees.
The shortage of bees in the U.S. has resulted in the increased long-distance transportation of honey bees to fertilize agricultural crops. This increases the stress on hives, making them even more prone to infection, and may also contribute to the further spread of disease.
The United States is already experiencing CCD. American beekeepers are importing bees from Australia which is so far unaffected, and some orchardists are utilizing solitary, non-honey producing mason bees for pollination.
The United Kingdom’s national bee database has drawn attention to the increasing incidence of bee disease, particularly a miticide-resistant strain of the varroa virus. They continue to monitor the situation, while at the same time trying to prevent CCD by raising awareness of the consequences of habitat destruction, providing training in beekeeping techniques and conducting research into bee diseases.
