Bees and other pollinators

DEFINITION: Flying insects and other biological agents that facilitate plant reproduction by moving pollen among seed plants

Pollinators such as bees are extremely important to the health of the planet because, without them, most plant species would disappear. Pollinating species are in decline around the world, a trend that threatens biodiversity and food supplies for many animals, including humans.

Bees are the best-known group of pollinators; however, other insects such as butterflies, wasps, beetles, and ants are pollinators, too, along with some species of bats and birds. Plants and their pollinators coevolved, forming symbiotic relationships in which plants provide food for the pollinators, which in turn aid the plants’ reproduction. Many other species evolved over time to take advantage of this fundamental relationship between plant and pollinator, including humans and other animals that eat the results of the fertilized plants, such as nuts, seeds, and berries. Pollinators also contribute to the web of life by ensuring the continued survival of plants through the process of pollination; the loss of pollinators can affect the biodiversity and well-being of a whole ecosystem. In the first three decades of the twenty-first century, declines in pollinator populations around the world led environmental groups and government agencies to include pollinators in their conservation efforts.

Pollinator Decline

The decline of pollinating species has many causes, all for the most part related to human activity. One cause is the use (and misuse) of pesticides meant to kill other insects, such as mosquitoes; such pesticides also indiscriminately kill off other insect populations, many of them pollinator species. Another cause of pollinator decline is the large-scale transport of pollinators around the world for agricultural purposes; this practice also results in the large-scale transport of parasites and diseases that affect them, as well as the introduction of invasive species that can compete with or destroy native pollinator populations.

Human expansion into previously wild or relatively untouched spaces contributes to pollinator decline through habitat loss and degradation, as development brings with it pollution, hive destruction, and fragmentation of traditional “nectar corridors.” Wild pollinators have fewer places to nest, mate, and roost safely, and their historic ranges have been destroyed or partitioned in such a way that it is far more difficult for them to find the nectar they need to survive. Globally, many pollinators are already on endangered or threatened species lists, including more than one hundred avian species and dozens of mammals. According to the US Fish and Wildlife Service, seventy species of pollinators were listed as endangered or threatened in the United States in 2020.

Climate change has also affected pollinators. A 2015 study found that warming temperatures had caused bumblebees' range to shrink by as much as 190 miles since the 1970s, with the bees staying farther and farther north as the climates in the southern parts of Europe and North America became less hospitable. A 2020 study published in Science confirmed that bumblebee populations had declined 46 percent in North America and 17 percent in Europe and that these declines correlated to higher temperatures and heat waves.

The Importance of Bees

The thousands of species of bees in the world are widely known for pollination and for their making of honey and beeswax. Bees are the primary pollinators of flowers around the world and are also responsible for the pollination of approximately one-third of the human food supply. Many agricultural crops, ranging from watermelons to cashews, rely on pollination by bees. European honeybees, in particular, are extremely important to agriculture because of humans’ ability to manage the species.

Pollination management, also called contract pollination, entails transporting honeybees in their hives to crops that are in need of pollination. Modern monoculture farming has created a situation in which the normal pollinators of some kinds of crops cannot pollinate them, either because of the huge size of the fields or because the pollinators have declined or died off. Honeybees, however, can be put in the fields in such large numbers that they make up for the fact that they are often less efficient pollinators than the native species that previously would have pollinated a particular crop. The economic viability of monoculture agriculture often depends entirely on pollination management, and most professional beekeepers in the twenty-first century focus on contract pollination rather than honey as their primary source of revenue.

The same factors that have caused declines in other pollinator populations since the late twentieth century and into the twenty-first century have affected honeybees as well, causing a widespread honeybee population decline. In addition, across North America and Western Europe since at least 2006, honeybees have disappeared in what is called honeybee colony collapse disorder (CCD), the cause of which remains a mystery. CCD is characterized by the worker bees flying off and never returning to the hive or colony, leaving behind a healthy queen, an unhatched brood, and food supplies.

Given the importance of honeybees to agriculture around the world, scientists have investigated many possible causes for CCD; possibilities include a parasitic mite, insect diseases, and the use or misuse of insecticides. Some researchers have reported evidence that it may be viral. These possibilities are aggravated by other factors negatively affecting honeybee populations, such as poor diet related to monoculture, which can lead to malnutrition or impaired immune system, and migratory beekeeping, which spreads parasites and diseases among populations. One such disease, known as deformed wing virus after its chief symptom, became a serious threat to honeybee and bumblebee populations in the 2010s; a 2016 study found that the trade in pollinators was directly responsible for spreading the virus around the world. Fortunately, the Environmental Protection Agency reported in 2022 that instances of CCD had been trending downward since 2017.

Following decades of decline, in 2024, the US Department of Agriculture reported that America’s honeybee population was at an all-time high of 3.8 million bees. However, this number represented the number of honeybees kept in colonies on farms and did not consider wild bees, a population that experts believed to be many magnitudes higher. Experts attributed the growth to several factors, including increased interest in beekeeping as well as tax breaks for farmers that keep bee colonies on their property.

Many pollinators are very small, but their importance to terrestrial life is great. Pollinators are a major part of the web of life, and what happens to them can affect every other creature in an ecosystem. Plants, whether they are cacti in the desert of Mexico or blueberries in Scotland, need their pollinators to survive—without pollinators, a plant cannot reproduce, and its species will go extinct. If this occurs, the pollinators adapted to that plant will no longer have a food supply and will either starve to death or switch to another source of nectar, inevitably intruding on another animal’s food supply. As the plants disappear for lack of pollinators, animals such as birds, small mammals, and lizards that eat the fruit, nuts, and seeds produced by pollinated plants will also begin to starve. This effect will ripple through the food web until it reaches larger animals, including human beings.

Bibliography

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