Bees face a serious threat — and so do we. The threat comes from what’s known as Colony Collapse Disorder (CCD). This occurs when the worker bees simply disappear from a hive, leaving behind the queen bee, a few nurse bees and countless baby bees. With no mature worker bees to bring nectar and pollen back to the hive, the colony collapses and dies. The main causes of CCD include loss of habitat, diseases and parasites, pesticides and environmental factors. Learning more is the first step to becoming Beesponsible. Then it’s time to do something.
Loss of Habitat
Many bees and butterflies thrive only in specific habitats. So when those habitats are profoundly changed, such as through land development for urban, suburban and agricultural uses, this can be detrimental. Losing their habitats means pollinators lose the places where they overwinter and forage for pollen and nectar.
Off-road vehicles or even heavy foot traffic can affect the quality of the habitats of ground-nesting bees, compacting the loose soil they need. In cities, ground-nesting species lose their habitats when increasing amounts of landscape are paved with concrete.
Pollinators’ habitats also decline when they are broken up and disconnected from each other by road construction, development or agriculture. Creating safe passages between isolated patches of habitats helps pollinators survive in these areas.
Parasites and Diseases
Parasites and diseases pose a serious threat to pollinators. This includes the mite and virus species that have severely compromised honeybee colonies over the past decade. Bees’ most dangerous enemy is the varroa mite, which feeds on the blood of adult honeybees and reproduces on honeybee pupae. Varroa mites spread among colonies via drifting workers and drones, along with the robbing of honey from infected hives. Once present in a colony, varroa weaken bee immune systems and transmit a variety of deadly viruses including deformed wing virus.
Other diseases that affect honeybee populations include the highly contagious American foulbrood, which kills larvae and ultimately the entire colony. Nosema ― a widespread disease caused by ingestion of contaminated spores ― affects the gut and digestive tract of adult honeybees.
Despite certain treatment methods for varroa mites and some diseases, these pervasive threats continue to pose a major challenge to beekeepers and honeybee populations.
Pesticides and Pollution
Pesticides and drift from aerial spraying — especially spraying with chemicals that remain in the environment for a long time before degrading — threaten insect pollinators. In particular, neonicotinoids (a certain class of insecticides) pose a toxic threat when absorbed into plants fed upon by bees. Even sublethal amounts of neonicotinoids can be detrimental to bees and other pollinators by disrupting their ability to navigate or forage. Herbicides that eradicate important forage plants for bees and other pollinators also present a threat.
Air pollution contributes to the problem by disrupting bees’ and other pollinators’ natural ability to detect floral scents. When plant-emitted scent molecules interact with air pollutants, the molecules begin to break down. This confuses bees, causing them to spend more time foraging and less time pollinating.
The mutually beneficial relationship between plants and pollinators depends largely on phenology (the timing of natural events within plant and animal life cycles). In other words, the time when flowers decide to bloom must match with the time when bees decide to forage. Gradual changes in long-term weather patterns ― including temperature, rain and sunlight ― can alter environmental cues and disrupt this delicate balance.
For example, warmer-than-usual temperatures affect the time of day certain plant species produce flowers, nectar and pollen. Some bees, on the other hand, may respond by altering the time of day they choose to forage (or limiting their foraging distance) to avoid overheating. Unseasonable warmth or increased precipitation may prompt crops to flower earlier in the growing season, before their primary pollinators.