Blake Layton is Extension Entomology Specialist at Mississippi State University.
 

 
 

The Trouble With Honey Bees
by Blake Layton - posted 05/19/17

Honey bee queens are easily identified by their much longer abdomens. Queens spend their days laying eggs while being fed and tended by workers.


Honey bees hold a unique place in the insect world. They are one of only a few insects man has domesticated, and they are bred and raised as livestock throughout the world. The honey and wax they produce has been prized by humans for thousands of years and honey bees provide critical pollination for many food crops. These are valuable insects that enhance our lives. Commercial beekeepers derive their livelihood by farming this miniature livestock, and even if you do not keep bees, eat honey or use beeswax candles, many of the fruits and vegetables you eat are more readily available and less expensive because of honey bee pollination.

Honey bees are not native to North America; they were brought here by European settlers to provide honey and beeswax. As settlers moved west they carried honey bees with them, and many of these bees escaped along the way to establish feral colonies in hollow trees throughout the country. But feral honey bee colonies are not nearly as common as they once were, and neither are domestic colonies. According to the National Agricultural Statistics Service, the number of commercial bee hives in the U.S. peaked at 5.9 million in 1947; today there are less than 2.5 million.

If you have paid attention to the news media over the past few years, you probably know honey bees are having problems. One of the most widely publicized is a phenomenon known as colony collapse disorder, or CCD. This problem, which causes entire colonies of bees to die suddenly and mysteriously, was first recognized in the U.S. in 2006. But CCD is just one of a series of new problems to affect U.S. honey bees over the last 30 years.

Like all livestock, honey bees are subject to a wide variety of health problems. Many of these health problems are diseases, but honey bees are also affected by parasitic mites, exposure to insecticides, other insects that invade the hive, and even other honey bees. Keeping colonies healthy and vigorous is one of the most effective proactive treatments for many of these problems, but with so many new problems this is more difficult and more costly for beekeepers to do.


Male honey bees, called drones, are larger and stockier than workers and have bigger eyes. Drones do not collect nectar and pollen or perform tasks within the hive.


Diseases
Many people are surprised to learn insects get sick, but they do, and honey bees are no exception. There are many diseases that are specific to honey bees. These include diseases caused by bacteria, fungi and viruses. Some of these diseases affect the brood, or immature stages, while others affect adult bees. Historically, the most serious brood disease is a bacterial disease known as American foulbrood. Infected larvae die in their cells and worker bees spread the disease as they routinely clean cells and feed larvae. Back in the 1960s when quarantining and destroying infected colonies was the standard method of treating American foulbrood (it still is in some states), I had to burn several of my own colonies because of this disease.

There are several other less serious, but still debilitating, brood diseases, including European foulbrood, sacbrood and chalkbrood. Nosema diseases affect adult honey bees. Nosema apis is an “old” disease that afflicts bees that are winter bound inside the hive for too long, causing dysentery and gradually weakening the colony. Nosema ceranae is a relatively new and more serious problem that can cause infected colonies to die out quickly.

Honey bees are also affected by many viruses. With the exception of N. ceranae and some of the viruses, most of the problems mentioned so far have plagued U.S. beekeepers for hundreds of years and both bees and beekeepers are somewhat used to coping with these problems. Many of the problems we are about to discuss are relatively new to the U.S. beekeeping industry, and, in some cases, the best ways of dealing with these problems are still being worked out.


Mites
During the 1980s two species of parasitic mites entered the US, causing serious problems for the beekeeping industry and destroying most of the feral honey bee colonies that had become so common through much of the country. Tracheal mites attack adult bees by crawling inside their trachea or breathing tubes and sucking blood through the tracheal wall. For humans, this would be similar to having ticks feeding on the insides of the nostrils. Varroa mites are much larger than tracheal mites and attack developing bee larvae and pupae, as well as adult bees, by sucking blood through the body wall, earning them the nickname “vampire mites.” This is debilitating enough, but varroa mites also spread a viral disease that causes adult bees to have deformed wings. Either of these mites can cause a colony to die out and beekeepers must now spend considerable money and effort to protect their colonies from these pests.

 

This frame of brood shows some of the things you will see inside a healthy honey bee hive: adult worker bees, capped brood, containing pupating worker bees (center of frame), open cells with white larvae curled in the bottom, open cells containing newly laid eggs, a band of capped honey (along the top of the frame) and capped drone brood (lower corners of the frame).


Insecticides
One of the dilemmas of beekeeping is that honey bees are needed to pollinate certain crops, yet those same crops are attacked by insect pests that sometimes have to be controlled with insecticides. Honey bees also forage on a large number of crops that do not require bee pollination, and foraging workers will fly several miles from the hive. If insecticides are applied when honey bees are foraging in a crop, large numbers of workers can be killed. Beekeepers are familiar with this problem and work to minimize the risk by carefully choosing where, and where not, to place their bee yards and by moving or confining their bees when insecticide applications are scheduled for a crop they are pollinating. Farmers can help by notifying beekeepers before applying insecticides and by scheduling applications late in the day after most bees have ceased foraging.

Although the impact of agricultural insecticides on honey bees is a controversial subject, this may be one of the few honey bee problems that has declined over the past few decades. This is because many of the older broad-spectrum insecticides that are acutely toxic to honey bees have been replaced by products that are more pest specific and less acutely toxic to bees and other non-target organisms. However, there are questions about the potential chronic effects of some of these newer insecticides on honey bees and research continues in this area. The wide-spread use of transgenic (genetically modified) crops, which produce their own internal control of certain key insect pests, has benefited honey bees by reducing the number of foliar insecticide sprays required on many crops. Transgenic crops also are not without controversy – “If these plants produce their own insecticide how does it affect honey bees?” This question must be carefully researched and answered before a transgenic crop is approved. Results of extensive and ongoing research have shown no adverse effects from the transgenic crops currently in use.


Africanized Honey Bees
African honey bees are a subspecies of honey bee that is native to Africa; “European honey bees” refers to several subspecies of honey bees that are native to Europe. There are several key behavioral differences between African honey bees and European honey bees, the most important being that they are much more aggressive and attack with less provocation and in larger numbers. This behavior has earned them the name “killer bees” because their massive attacks sometimes result in human fatalities.

In the 1950s, a few African honey bee queens escaped from a bee breeding program in Brazil and began to interbreed with commercial and feral European honey bees. These “Africanized honey bees” spread through South America, moved into Mexico, and entered the U.S. in 1990. Today, feral colonies of Africanized honey bees are established in all the Southwestern states, as well as in portions of Louisiana, Arkansas, Florida and Georgia, and they continue to slowly spread into the remainder of the Southeast. In addition to interbreeding with European honey bees, Africanized bees will also invade and take over weakened colonies of European bees.

Despite decades of interbreeding with European honey bees, Africanized honey bees still retain their aggressive behavior. Because of the increased potential for mass stinging attacks, gardeners and the general public need to be much more cautious around colonies and swarms of feral bees once Africanized bees arrive in an area. Your state’s department of agriculture and local county extension offices can provide more information about Africanized honey bees and the steps and precautions to take when suspected colonies are encountered. Commercial beekeepers can prevent apiaries from being taken over by Africanized bees by regularly re-queening with purebred queens produced in areas where Africanized bees do not occur.


A solid frame of freshly capped honey is a beautiful sight that represents thousands of “bee hours” of work.


Wax Moths and Small Hive Beetles
Honey bees also have to contend with other insects that will invade their hives and steal the fruits of their labor. Wax moths are age- old enemies that cause millions of dollars of damage to the U.S. bee industry each year by damaging combs and equipment. The moths invade the hive and lay eggs and the caterpillars tunnel through the comb, producing large amounts of silken webbing. Weakened colonies or stored combs are most likely to be attacked; healthy vigorous colonies are usually able to defend themselves against wax moths.

Small hive beetles invaded the U.S. around 1996 and have since spread throughout the country. Adults and larvae crawl over the combs feeding on honey and pollen and contaminating honey and causing it to spoil. They also feed on immature bees, and heavy infestations can cause bees to abandon a hive. As with wax moths, small weakened colonies are most susceptible, but small hive beetles sometimes invade healthy colonies and beekeepers are still working out the best way to control this pest, which now exceeds wax moths in importance.


Colony Collapse Disorder
In 2006, commercial beekeepers began to notice large numbers of hives in which most of the adult bees had suddenly disappeared, leaving the queen and immature brood to die in the hive. Dead adult bees are not found either inside or around the outside of affected hives – they are just gone. This is a serious problem with some beekeepers suffering the loss of more than half their colonies to this phenomenon. Greatest losses occur through the winter and into early spring. Beekeepers normally lose around one of every six colonies to winter mortality, but approximately one third of all honey bee colonies were lost in each of the first two winters after this new problem was recognized, and U.S. honey bees continue to suffer high mortality from this mysterious malady.

This problem is called colony collapse disorder (CCD), and the beekeeping industry is devoting large amounts of time and resources into determining the cause of CCD. So far no single agent has been identified as “the cause” and CCD is currently considered to be a syndrome caused by several contributing factors. Many potential factors have been investigated and many, such as cell phones and transgenic crops, have been largely dismissed as being involved. Some of the factors that continue to be investigated include: varroa mites; a virus disease known as Israeli acute paralysis virus; and Nosema ceranae, a relatively new disease of adult bees. Insecticides have not been exonerated as playing a role in CCD, but despite extensive research, they have not been definitively implicated either. Progress is being made, but honey bee researchers are still working frantically to understand just what causes this serious problem and how to stop it from killing U.S. honey bee colonies.

As you can see, it is not easy being a honey bee; there are so many potential problems that can affect the hive. Some are serious problems that can kill a colony quickly. Others are more minor problems that can weaken a colony and make it more susceptible to other diseases or pests, resulting in a lingering decline. This spring, when you notice a honey bee working some of the flowers in your garden, take a minute to consider and appreciate the benefits she and her sister bees provide, despite the problems they face.

 

A version of this article appeared in a February 2011 print edition of State-by-State Gardening.
Photography courtesy of Blake Layton.

 

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