In the six years leading up to 2013, more than 10 million beehives were lost, often to Colony collapse disorder (CCD), nearly twice the normal rate of loss.
Several possible causes for CCD have been proposed, but no single proposal has gained widespread acceptance among the scientific community. Suggested causes include: infections with Varroa and Acarapis mites; malnutrition; various pathogens; genetic factors; immunodeficiencies; loss of habitat; changing beekeeping practices; or a combination of factors. A large amount of speculation has surrounded a family of pesticides called neonicotinoids as having caused CCD.