The No. 1 stressor on honeybee colonies is varroa mites. Largely found in Florida, these mites feed off of adult honeybees and those unhatched or maturing (called brood). The mites actually develop on the honeybee brood, allowing them to overtake adult bees as they grow, and move from colony to colony by attaching themselves to agricultural workers and drones.
Other pests and parasites like tracheal mites, small hive beetles, and wax moths, as well as the disease nosema, are also having a negative impact on the health of the honeybee population. Hive beetles are native to the sub-Saharan areas of Africa but have been found outside of the region around nests of the honeybee.
Pesticides, weather, and diseases have also had significant adverse impacts on the honeybee population in the U.S., together accounting for over 20 percent of colonies lost in 2015 and 2016.