A study to be released on Friday will report the widespread movement of bee colonies around the world is to blame for their plummeting populations. The article in journal Science examines how  bee disease DWV (Deformed Wing Virus) has spread globally because of the volume of unregulated trade between continents.

Scientists believe the Varroa mite has played a huge part in the rapid decline of bees. The tiny mite feeds specifically on bee larvae, whilst also injecting toxins into the bodies of healthy adult bees. It’s believed this damaging double threat has been responsible for killing millions of colonies over the last few decades.

Lead author of the study, Lena Bayer-Wilfert of the University of Exeter, England, said “Varroa mites feed on honeybee hemolymph or ‘blood’…they can get infected or contaminated when they feed on infected honeybee larvae and can then in turn pass on the virus to new bee larvae.”

The spread of the Varroa mite was studied extensively as part of the research. A DNA database was used in conjunction with information taken from some 17 countries globally.

Analysis revealed the spread of the disease could be traced from a source in Europe, and from there to North America, New Zealand and Australia. Humans were “to blame” for the spread of the pandemic because of the sheer volume of trade in colonies, and lax checks on bees’ health.

“This study shows the risk of moving animals and plants around the world,” said Professor Roger Butlin, of the University of Sheffield in the UK. “The risk of introducing viruses or other pathogens is just one of many potential dangers,” he added.

Report authors and experts say there needs to be better screening for bee populations and more scrutiny of the international trade in colonies.  The honeybee is critical in modern agriculture for its role in pollination – and for honey production.