Parasites, Poison, and Single Plant Crops: A Study of the Decline of the Honeybee

By Elissa Hays

What would happen if honeybees disappeared from the Earth?  Albert Einstein is famously attributed with making the statement that if honeybees became extinct that life on this planet would cease to exist within four years. Einstein most likely did not actually make this comment, and due to the nature of pollination this theory is not accurate.  However, life would drastically change. In the United States honeybees are responsible for the pollination of approximately 35% of the fruits, vegetables, and nuts produced (Yang).  Not only are honeybees directly responsible for 35% of our food sources, apiculturists theorize that they indirectly help produce as much as 75% of the United States food sources via the food chain (Pollinators Vital to Our Food).  Beginning in the early 2000’s, beekeepers across the United States of America began to notice an alarming phenomenon.  Bees were disappearing.  By 2006 beekeepers across the nation were reporting high volumes of colony mortality. This trend of colony loss continues today in what has previously been dubbed Colony Collapse Disorder (CCD).  When considering the plight of the honeybee, understanding the causes leading to colony collapse such as agricultural monocultures, chemical use in agriculture, and honeybee pathology is imperative.

Monocultures impair honeybees health due to the introduction of inferior genetics, and diseases in which bees from different regions have no way to combat.  Monoculture is the agricultural practice of planting massive fields of a single crop.  When thinking about monocultures one can imagine the vast almond groves in California, orange groves in Florida, blueberries in Maine, and apple orchards in Washington.  In order  to make it possible for these vast crops to produce a harvest, monoculture farmers must rely on honeybees to pollinate their crops.  To ensure that there are appropriate amounts of bees, bees are trucked into the monoculture areas from all over the country.  Mobile apiaries are any number of hives that are moved from one location to another based on nectar and pollen sources or pollination contracts.  Most mobile apiaries are at minimum, moved four times per year.  This constant movement from region to region puts stress on bees health shortening their natural lifespan.  When bee colonies lose their queen a new queen must be made from the available brood in the hive.  After a newly made queen hatches she must go on her virgin mating flight.  This is where one of the problems arise.  Different areas of the country import different species of bees.  While some of these species have very strong genetics, other species may have weaker genetics which open the new queens future brood to a host of health problems.  Another issue that arises from migratory apiaries is that as honeybees are being shipped in from all over the country so are diseases common to specific regions.  Honeybees from different regions of the country are now being exposed to parasites, viruses, and bacteria that they would not necessarily encounter in their region, and have no defense against.  These bees are then returned to their home state, and introduce these new diseases to the native honeybee population thus spreading diseases that are unable to be combated.  This practice causes widespread problems for honeybees and beekeepers alike.

Herbicides and pesticides  are commonly used in American homes and agriculture, but one must consider the ramifications to honeybee health when using such harsh chemicals.  There are two major chemicals used in agriculture that affect honeybee health, glyphosate and neonicotinoids.  Glyphosate is an herbicide used to kill weeds both in large agricultural productions as well as every day home use.  It is sold in most hardware and garden stores.  One may know it more commonly as Roundup.  According to the Environmental Protection Agency, Glyphosate has been deemed to have low toxicity to humans, mammals, birds, and Terrestrial invertebrates, which honeybees belong to.  However , if one examines the evidence available on toxicity in honeybees it can be concluded that glyphosate is not a benign as has been reported.  Ross Conrad, author of Natural Beekeeping: Organic Approaches to Modern Apiculture, in his article entitled “Glyphosate Safe for Bees and Beekeepers,” quotes from the Journal of Experimental Biology: “honeybee exposure to levels of glyphosate commonly found in agricultural settings (read: applied as Roundup) impairs the cognitive capacities needed to retrieve and integrate spatial information for a successful return to the hive.” (80).

Other research done on the subject has found similar result.  It has been theorized that Glyphosate impairs learning in honeybees and is more toxic than the EPA has lead the public to believe.

Neonicotinoids are a classification of chemicals that encompass several different pesticides used to control pests in agricultural crops.  The seeds of these plants are soaked in the pesticides resulting in trace amounts remaining within the plants once they sprout and flower.  The different chemicals can be found in the pollen and nectar of the plants which honeybee’s then ingest.  Neinicotinoid’s act similar to nicotine in the body, and have a profound effect on honeybee behavior.  These different chemicals have been found to affect the central nervous system.  In one study entitled “Exposure to Neonicotinoids Influence the Motor Function of Adult Worker Honeybees” scientists studied the effects of the four most common Neonicotinoid’s as well as Nicotine to ascertain the effect that the different chemicals had on honeybees.  It was determined that exposure to any of the chemicals in higher doses over a twenty-four hour period increased mortality rates within twenty-four hours of exposure.  What was more surprising was that bees exposed to lower doses of the same chemicals over a twenty-four hour period all displayed impaired motor function critical for hive longevity.  According to this study honeybees that had been exposed to neonicotinoids spent approximately 80% of their time walking and 5 to10% of their time standing still as opposed to only around 5% of time attempting to fly (Williamson 1412).  It was also noted that honeybees exposed to doses only slightly higher than normal exposure spent a significant amount of time on their backs unable to right themselves.  When examining honeybees exposed to these two chemicals it becomes apparent that both glyphosate and neonicotinoids impairs honeybees ability to return to the hive thus creating a shortage of not only viable workers, but also food.  This shortage of both workers and food both contribute to the decline, and eventual loss of hives many beekeepers are experiencing.      

There are many parasites, viruses, and bacteria that affect honeybee health.  In current news one will hear almost exclusively of the Varroa mite in relation to honeybee pathology and honeybee health.  The Varroa mite is a small mite about the size of a pinhead that lives their entire lifespan on honeybees.  As the nurse bees attend to the larvae, adult Varroa mites lay their eggs in suitable host cells just before capping of the individual cells. The mite that lay the eggs in the cell before capping will chew a hole in the developing bee where her eggs are laid.  Once the offspring mites hatch they will continue to feed from the original wound in which they hatched from. Varroa mite eggs will hatch in a certain order.  Male varroa will always hatch first followed by female Varroa.  The single male and multiple female Varroa will mate with each other and begin reproducing before the pupae has finished developing.  According to Keith S Delaplane author of First Lessons in Beekeeping, “if the bee survives this trauma, it emerges from its cell and the mated daughter mites emerge with it to disperse and renew the cycle” (123-124).  The honeybee that emerges from the cell contaminated by mites will be host to various deformities, virus’, and other pathology.  The most common deformity seen in mite infested colonies, and is a marker for beekeepers that one of their colonies is suffering from mite infestation is a phenomenon known as Deformed Wing Virus (DWV).  The hallmark symptoms of DWV are shortened wings, deformed wings, or a complete lack of wings.  Honeybees infected with Deformed Wing Virus may also display “shortened abdomens, and cuticle discoloration in adult bees” (Moore).  Bees who have deformed wing virus are unable to fly, and therefore usually do not survive long in the hive. The varroa mite is arguably the most prolific of the honeybee pests

Another aspect of Honeybee pathology that has lead to a decline in the population of honeybees is American foulbrood.  American Foulbrood is caused by the bacteria known as Paenibacillus larvae.  This bacteria is considered an orphan bacteria because it is “highly adapted to [its] specific host,” (Ebeling 7387) meaning that without the honeybee P. Larvae can not exist.  P. Larvae is a spore producing bacteria that infects the larvae’s intestinal tract causing infection. Larvae stage bee’s are the only ones that can be infected, and death of the larvae usually occurs just after capping.  This spore forming bacteria is transmitted from larvae to larvae by infected nurse bees during inspection and feeding times.  The classic identification of American foulbrood in hives comes not from any symptoms identifiable with the eye, but the potent smell that is released similar to the stench of dead fish.  When examining the hive beekeepers will notice a ropy black substance in the cells, which is the remains of infected larvae, along with an irregular brood pattern.  Once  American foulbrood is identified it has reached a stage that is very hard to treat, and colony loss is virtually inevitable.

When one begins to contemplate the importance of honeybees to the natural ecosystem it becomes apparent that change is needed to prevent even more loss.  Simple changes can be made at a personal level.  Instead of applying chemicals to treat persistent weeds choose more natural alternatives such as hand-weeding, or burning weeds to kill them off. One can also apply natural weed killers such as a dish soap, salt, and vinegar solution to unwanted plants. Choose to buy plants and seeds which have not been treated with neonicotinoids.  When choosing produce, shop locally sourced produce over items that have been shipped in from all over the country, or world.  Farmers Markets are a wonderful source of local goods, which support farmers, and small production beekeepers within ones own community. Finally invest in pollinator friendly plants to encourage local pollinators of all kinds.  With small adjustments one can impart major change. 

 

Works Cited

Conrad, Ross. “Glyphosate Safe for Bees and Beekeepers.” Bee Culture, Nov. 2018, pp. 80-82

Delaplane, Keith S. First Lessons in Beekeeping, Dadant & Sons, 2007.

Ebeling, Julia, et al. “Biology of Paenibacillus Larvae, a Deadly Pathogen of Honey Bee Larvae.” Applied Microbiology and Biotechnology, vol. 100, no. 17, 2016, pp. 7387-7395. ProQuest, https://login.proxy189.nclive.org/login?url=https://search.proquest.com/docview/1810624017?accountid=15152, doi:http://dx.doi.org/10.1007/s00253-016-7716-0.

Moore, Philip A, Michael E. Wilson, John A. Skinner, “Honey Bee Viruses, the Deadly Varroa Mite Associates.” Extension Issues, Innovation, Impact A Part of the Cooperative Extension Systems, 29 Nov. 2016, https://articles.extension.org/pages/71172/honey-bee-viruses-the-deadly-varroa-mite-associates.

Pollinators Vital to Our Food Supply Under Threat.” Food and Agricultural Organization of the United Nations, www.fao.org/news/story/en/item/384726/icode.docview/1898644393?accountid=15152, doi:http://dx.doi.org/10.1038/srep32023.

Williamson, Sally M., Sarah J. Willis, and Geraldine A. Wright. “Exposure to Neonicotinoids Influences the Motor Function of Adult Worker Honeybees.” Ecotoxicology, vol. 23, no. 8, 2014, pp. 1409-18. ProQuest, https://login.proxy189.nclive.org/login?url=https://search.proquest.com/docview/1562334530?accountid=15152, doi:http://dx.doi.org/10.1007/s10646-014-1283-x.

Yang, Sarah. “Pollinators Help One-Third of World’s Crop Production, Says New Study.” UC Berkeley Press Release, UC Berkely, 25 Oct. 2006, https://www.berkeley.edu/news/media/releases/2006/10/25_pollinator.shtml.