Pesticide Exposure
Neonicotinoid insecticides can impair bee navigation, foraging, and immune function. Field-realistic exposure levels have been linked to reduced colony survival, especially when combined with other stressors.
Habitat Loss and Nutrition
Conversion of wildflower meadows and grasslands to cropland reduces the diversity and abundance of bee forage. Limited nutrition weakens colonies and makes them more vulnerable to disease and environmental shocks.
Disease, Parasites, and Management Pressures
The varroa mite is a primary driver of honey bee losses, transmitting viruses and suppressing bee immunity. Other pathogens, such as Nosema, and management practices like long-distance transport for pollination services can further increase colony stress.
Climate and Environmental Factors
Shifts in temperature and precipitation timing can desynchronize bee activity from flower availability. Extreme weather events and altered landscapes compound existing pressures, contributing to regional declines in honey bee populations.
Learn more about pollinator health and monitoring data from the U.S. Geological Survey at Pollinator Health Resources.
