January 18, 2017

For the first time in the continental United States, a wild bee has been designated as an endangered species. What was once a thriving bee in 28 states and 2 Canadian provinces, the rusty patched bumble bee is now weakly carrying on in scattered populations in just 13 states and the province of Ontario. In the past 20 years, the insect’s population has dropped 87 percent because of habitat loss, disease, pesticides, and climate change. In 2013, the Xerces Society for Invertebrate Conservation filed a petition for the rusty patched bumble bee to be listed as an endangered species, but it took until last week to make it happen.

The rusty patched bumble bee (Bombus affinis) was listed as an endangered species in January 2017. Credit: © Rich Hatfield, The Xerces Society

The bumble bee is a large, burly bee that often has mostly black-and-yellow coloring. Bumble bees may be seen flying among flower blossoms during spring, summer, and fall. The rusty patched bumble bee lives only in the upper Midwest and northeastern United States and in Ontario. Like most bumble bees, rusty patched bumble bees have black heads, but workers and males have a rusty reddish patch on their backs.

Bumble bees are among farmers’ best friends, and protecting them is important. They pollinate (help fertilize) numerous wild plants and such food crops as blueberries, cranberries, clover, and tomatoes. The agriculture industry leans heavily on such native pollinators as bumble bees.

Now that the rusty patched bumble bee is listed under the Endangered Species Act, the Fish and Wildlife Service must assess, protect, and help restore the insect’s population and habitat.

By protecting the environment, people can help save the rusty patched bumble bee. On an individual level, you can help simply by growing a garden. A garden of plants native to your region will attract and nurture native pollinators. Bumble bees love lupines (such as peas), colorful asters, and, as its name implies, bee balm (flowers that also attract nectar-loving butterflies and hummingbirds). Choose a variety of colorful plants that flower at different times, providing nectar and pollen throughout the growing season. Limiting or avoiding the use of pesticides and chemical fertilizers also helps, because they can kill or seriously harm bumble bees.

November 21, 2016

The Asian giant hornet is so large, it is sometimes mistaken for a small bird in flight. This big predator is equipped with piercing jaws, a quarter-inch-long (half-centimeter-long) stinger loaded with deadly venom (poison), and an aggressive disposition. It keeps beekeepers up at night and is responsible for the deaths of dozens of people each year.

The Asian giant hornet is the largest of its kind. Credit: Yasunori Koide (licensed under CC BY-SA 4.0)

The Asian giant hornet (Vespa mandarinia) is the largest hornet in the world. Workers grow up to 1.75 inches (4.5 centimeters) long, and queens can grow even larger. They are found throughout Japan and Southeast Asia. Asian giant hornets make their nests in the ground or in hollow logs in wooded regions, but they also often venture into urban areas looking for food. These flying insects are extremely aggressive and quick to sting. Asian giant hornet venom is not more dangerous than the venom of other hornets or wasps, but these giants deliver more venom when they sting. And, because of the hornets’ violent swarming behavior, victims are often stung many times at once by many different hornets. Asian giant hornet venom destroys flesh and red blood cells and, if it is delivered in a large enough dose, can lead to cardiac arrest or kidney failure. In Japan alone, Asian giant hornets kill about 40 people and injure some 1,500 others each year.

Asian giant hornets prey on such large insects as beetles and praying mantises. After the victim is stung and killed, adult hornet workers take the insect carcasses back to the nests. There, the dinner is ground up and fed to larvae (young), which in turn produce a nutritious secretion for the workers. Also, adult hornets sometimes feed on tree sap or rotting fruit.

One remarkable behavior of the Asian giant hornet is its tendency to swarm and attack beehives to eat the honey. A scout hornet will locate a beehive and then lead groups of other giant hornets in an attack. The hornets then break into the hive and, using their powerful mandibles, sever the heads of the much smaller bees. Bees cannot sting through the hornets’ thick armor, so they are helpless against such an attack. An Asian giant hornet can kill a honeybee in seconds, so a few dozen hornets can completely destroy an entire hive of thousands of bees in a few hours.

Some kinds of Asian honeybees have developed a defense, however, to stop a hornet invasion before it happens. When an Asian giant hornet scout enters the hive, the bees swarm to it. The hornet may kill the first few defenders, but the bees quickly cover and immobilize (prevent from moving) the invader. Once the bees have trapped the scout, they begin to shiver their wings and bodies, generating heat. The trapped hornet eventually overheats and dies. This strategy costs the lives of many honeybees, both from being killed by the hornet and from overheating themselves. But their sacrifice can save the hive. The hornet scout doesn’t live to reveal the location of the hive, thus preventing an invasion.

Some environmentalists fear that the Asian giant hornet will invade other continents, particularly because of the uncertain effects of global warming. Isolated sightings have already been reported in the United States and Europe. Many of these sightings may be cases of mistaken identity, however, as these areas have their own large species (kinds) of wasps and hornets. Outside the Asian giant hornet’s native range, honeybees have not evolved (developed over time) the swarming behavior to defend against scouts. Non-Asian bees are at great risk, then, from Asian giant hornets. Many bee populations beyond Asia are already severely threatened by changes in land-use patterns and a mysterious disorder that causes bee colonies to collapse. In addition, a class of insecticides called neonicotinoids has already crippled honeybee populations. Invasions of Asian giant hornets could prove the end of honeybees in general.

 April 29, 2013

The European Commission (EC), the executive body of the European Union, banned the use of insecticides that some researchers have linked to the collapse of bee colonies. Some scientists believe that neonicotinoids—a new class of insecticides chemically related to nicotine—are harming bees. Nicotine is a natural insecticide that is fatal to many insects but less harmful to mammals. Until recently, nicotine-related insecticides were also believed to be less harmful to beneficial insects than traditional formulations.

A recent study in the journal Science, however, linked the use of certain neonicotinoids to a dramatic decrease in queen bees. Another recent study in Science linked insecticide exposure in bees to the problem of forager bees—worker bees that collect nectar
and pollen—having difficulty finding their way back to their hives. The chemical apparently affected the homing ability of the bees.

A bee, covered in pollen, sips nectar from a flower. Many flowers and kinds of food crops depend upon bee pollinators. (© Steve Hopkin, Taxi/Getty Images)

Scientists and environmentalists are very concerned about the health of bees. Honey and other bees pollinate around one-third of the world’s crop production. In 2006, beekeepers in the United States began reporting that large numbers of bees were mysteriously disappearing from their hives—which became known as colony collapse disorder (CCD).  It soon became clear that this was a worldwide problem. Scientists are not certain of all the factors involved in CCD. Some of the causes considered likely include mites and other parasites and viruses. Even if these are the primary causes of CCD, however, it could be that certain insecticides weaken the bees and are causing them to be more vulnerable to illness.

The EC ruling states that the use of neonicotinoids should be restricted to crops not attractive to bees and other pollinators. Crops such as wheat and barley, for example, are not of interest to such insects. The EC is imposing a two-year restriction on the neonicotinoids—clothianidin, imidacloprid and thiametoxam—beginning no later than July 1, 2013.

Additional World Book articles:

• Biology (Back in time-2007)
• The Latest Buzz About Honey Bees (Special Report)

Additional articles and resources:

• Honey bees and Colony Collapse Disorder (United States Department of Agriculture website)
• Silence of the Bees (Public Broadcasting System (PBS) film produced for the series Nature concerning scientists race to solve the mystery of CDC

Jan. 5, 2012

A previously unknown parasitic fly found in dead and dying honey bees in northern California may be a major culprit in a mysterious condition that has ravaged honey bee colonies in the United States. This condition, known as colony collapse disorder (CCD), was first detected in 2006, when beekeepers in the United States began reporting that large numbers of bees were mysteriously abandoning their hives. Studies revealed that the bees had died away from their hives. By 2012, CCD had been blamed in the deaths of millions of honey bees. Scientists have found evidence that pesticides, mites, a fungus, or a virus that causes honey bee wings to develop abnormally may be involved in CCD.

The parasitic fly, Apocephalus borealis, lays its eggs in the bees’ abdomen. Several days later, the infected bees fly from their hives at night. Scientists have found some of the infected bees still alive but in a zombie-like state. The insects were walking in circles, with no sense of direction, and soon become unable to stand up. Scientists aren’t sure whether the bees are leaving their hives under the control of the parasite or are being kicked out by their hive-mates, who may be sensing that something is wrong. Other parasites are known for their ability to control the behavior of the creatures they infest. The bees may also be leaving on their own to prevent their hive-mates from becoming infested. After the bees die, newly born fly larvae crawl from their neck. A. borealis also infects and kills bumble bees and paper wasps. Scientists believe it is very likely that the parasitic flies spread to honey bees from bumble bees.

A bee covered in pollen sips nectar from a flower. The bee will leave some of the yellow pollen grains at other flowers it visits, pollinating them. Many flowers rely on insects for pollination. © Steve Hopkin, Taxi/Getty Images

Bees are among the most useful of all insects. They pollinate many fruit and vegetable crops, which provide about a third of the human diet. In the United States, bees pollinate more than 130 crops, with a yearly value of $15 billion. These crops include apples, nuts, soybeans, and squash.

Additional World Book articles

• Back in Time (Biology 2007)
• Frisch, Karl von
• The Latest Buzz About Honey Bees (a Special Report)