Causes of a Decline of Bees

Parasites, Disease and Mites

• Parasites, mites, disease, fungal disease, nutrition and a lack of genetic diversity are thought to contribute to the decline. The transportation and confinement of the bees contributes to the level of stress and ultimate death. In 2007, the varroa mite was considered a main contributor to the decline. The Israeli acute paralysis virus, carried by the mite, was evident in many of the bees tested.

Chemicals

• Though it was under debate by the Congressional Research Service in 2007, one of the possible contributors to the decline is chemicals, including pesticides and fungicides, which don't kill the bees but damage their development and navigational skills. The chemicals make their way up the plant into the flower and pollen. Bees mainly eat pollen. But the CRS cited conflicting reports of the effect of chemicals on bees. Use of some chemicals around bee environments in Europe, however, has been outlawed.

Cell Phones

• CNET UK reported in 2011 that cell phones could be a contributor to a decline in bee numbers. Research at the Swiss Federal Institute of Technology found the sound a bee makes changes when in close proximity to a cell phone. Bees communicate through sound, and the insects transmitted distress signals when the phone was placed in their hives. After 12 hours of exposure to the cell phones, they still sounded distressed. CNET noted the research implies colonies can break up and die after long exposure to cell phones.

Infection

• Bees are believed to be killed by an insect virus and fungus, according to Shan Bilimoria, a professor and molecular virologist. His team released a report in 2010 saying the study confirmed an association of the bees' death rates with virus and fungus but also said it didn't prove cause and effect. The team ground up dead bees and inspected the remains. They discovered a moth virus called insect iridescent virus and Nosema, a fungal parasite.