Tighter regs, more screening needed
Commercially managed honeybee colonies may be speeding the spread of disease to wild bee populations, according to a new study by a University of California, Riverside entomologist.
“Even in cases when the managed bees do not have a disease, they still stress local wild bees, making them more susceptible to disease,” said Peter Graystock, a postdoctoral researcher in the Department of Entomology and the lead author of a paper published online last week in the International Journal for Parasitology: Parasites and Wildlife.
Graystock’s study lists the problems managed bees cause and suggests avenues to limit further damage.
“The use of managed honeybees and bumblebees is linked with several cases of increased disease and population declines in wild bees,” Graystock said. “This is shown in various countries around the world and is not always because the managed bees are carrying a disease.
“Loss of wild pollinators will ultimately either reduce crop yields or increase the reliance on and cost of shipping in more managed bees. This increased cost will cascade down to consumers, raising the price of food we put on our tables.”
By studying various examples from across the world, Graystock and his colleagues came up with a list of recommendations to enable the use of managed bees while minimizing their impact on wild bees.
“The general perception is that managed bees are healthy and that there will be laws in place to prevent harm to the environment,” Graystock said. “The more you look into this though, the more you realize that many countries have inadequate or no laws for bee movements and when we are looking at a global industry, this affects everyone.
“Primarily, this includes frequently screening for disease in managed bees and the employment of strategies to minimize mixing between managed and wild bees,” he said.
He said the globalized trade in bees has enabled almost free movement of diseases around the world. The movement of honey bees, he said, is the likely cause of the emergence of two of the most harmful honeybee diseases in countless countries in the last 50 years, including the destructive Varroa mite.
The international trade in bumblebees has also spread unwanted insect parasites to Japan, North America and South America.
Transport of bees should be subject to more rigorous disease screening under a unified international regulations, the study found. The mixing of managed bumblebees with wild bees should be prevented by using nets over glasshouses containing managed bumblebees. Finally, the study recommends more conservation efforts to limit the effects of managed bee use in areas suffering wild bee declines.
There is no unified law to prevent diseased bee transportation and most bumblebee restrictions are based on honeybee diseases, with little to no requirement to look for bumblebee diseases,” Graystock concluded.