What is one of the main threats to honeybee colonies besides varroa mites?

Pesticide exposure is indeed a significant threat to honeybee colonies. Many pesticides, particularly neonicotinoids, have been shown to have detrimental effects on bee health. When bees come into contact with these chemicals, whether through contaminated nectar and pollen or direct exposure during application, it can lead to disorientation, impaired foraging abilities, decreased reproductive success, and even death. This toxic impact severely affects not only individual bees but can also undermine entire colonies, contributing to population declines.

While competition from wild bees, changing floral resources, and climate change also pose threats to honeybees, they do not have the immediate and acute impact that pesticide exposure can have. Wild bees compete for food resources, but they also play a role in pollination alongside honeybees. Changing floral resources may affect honeybee foraging but relate more to landscape management and availability of flowers rather than a direct, toxic threat. Climate change influences weather patterns and floral availability over time, which can alter bee populations and health but typically does so gradually rather than through sudden toxic exposure.