In the minds of many, bees aren’t exactly one of the greatest elements of the “great outdoors.” Their stings are painful, and for those who are allergic, can induce deadly anaphylactic shock. But the precipitous decline of honeybee populations in North America and worldwide in recent years isn’t a cause for the celebratory burning of epinepherine injectors; the loss of these bees could have disastrous consequences for our food supply.
Bees play an essential role in global food production – and not just because they make honey. Much more importantly, bees act as pollinators for a wide variety of plant species, including many of the agricultural crops that appear in our daily diets. So many plants that humans rely on, from the cotton we wear to the fruits and vegetables on our table, from our morning coffee to the agricultural feed eaten by our meat and dairy livestock, rely wholly or in part on honeybees to complete their reproductive cycles.
Plants and bees have been shaping one another’s evolution for millions of years. Flowers produce the nectar and pollen that bees depend on as food sources. As each bee moves from one flower to another to gather these resources, pollen clings to its body and is carried between flowers, fertilizing the next generation of plants. Many of the foods we eat every day owe their existence to honeybees.
This dependence on honeybees for so many of the foods we take for granted makes their declining numbers all the more concerning. In the past 70 years, the population of honeybees in the US has plummeted by almost 60 percent. Some bee colonies fail every winter, but a poorly-understood condition known as Colony Collapse Disorder (CCD) causes those losses to nearly double in affected areas. Unlike more normal losses, CCD is not marked by the presence of piles of dead bees around the colony. The disorder causes adult worker bees to abandon a seemingly functional hive en masse, leaving behind their queen, her immature offspring, and plenty of food stores.
Part of the reason that Colony Collapse Disorder remains so little-understood is that there isn't just one direct cause. One major culprit appears to be a class of pesticides called neonicotinoids, and one in particular: imidacloprid, the world’s most widely used insecticide. Imidacloprid is less toxic to mammals and birds than other popular insecticides, but research indicates that it can be highly detrimental to bees even in concentrations that are too low to kill them. Symptoms of imidacloprid exposure in bees can include disorientation and failure to return to the hive, suppressed immune systems, and diminished reproductive potential in queens.
Imidacloprid alone cannot explain widespread CCD, however. Other chemicals likely play a role, including fungicides and antibiotics used by commercial beekeepers. The demands of modern agriculture have given rise to “rental bees,” mobile bee colonies hired out for their pollination services. This travel allows for the transfer of parasites and pathogens among different bee populations, exposes traveling bees to different types of pesticides and pollutants from different crops, and puts stress on the bees. Just like in humans, stress weakens the bees’ immune systems.
Climate is another major factor that impacts bee populations. Bees don’t forage in the rain, and they suffer in drought conditions. Anthropogenic climate change is causing the traditionally temperate, humid habitats occupied by honeybees to shift into more extreme weather patterns, putting additional pressure on the colonies in those areas – while simultaneously altering the abundance and growth seasons of the flowers those bees rely on for food. Taken together, this spells catastrophe for bees, and for humanity.