Honey Bee Colony Collapse Disorder

From Dickinson College Wiki
Jump to: navigation, search

Colony Collapse Disorder

Honey Bees

Enviromental Economics Wiki Page: Honey Bee Colony Collapse Disorder

Introduction

Brief Intro to CCD:

Honey Bee Colony Collapse Disorder (CCD) occurs when the majority of worker bees in a hive leave, abandoning the brood, honey stores, and queen bee. With the majority of the population gone, a hive cannot successfully function and collapses. CCD has accounted for beekeepers losing 45-90% of their hives in a season during recent years. Research points to multiple factors contributing to CCD, including hive stresses, weakened immune systems, pesticide poisoning, and various honey bee mites and diseases. CCD has primarily been a problem in the United States, Europe, and South America (Brackney 24).

KR 5


Background on Honey Bees:

First discoveries of honey by people are thought to be accidental; ancient people coming across abandoned hives in fallen trees and removing honey. First archaeological signs of beekeeping are from ancient Egyptians, who kept cylindrical hives in order to use honey as a form of currency and as medicine. Beekeeping then spread to Europe where it became popular in Greece, Rome, and Russia. Modern beekeeping techniques began to develop in the 1700s in eastern Europe. Honey bees (Apis mellifera) arrived to the United States in the 1600s, imported by European settlers. Since then, hive management techniques have developed and large-scale commercial beekeeping started in the early 1900s (Buchmann 10).

KR 4


Importance of Bees and Pollinators:

Honey bees play a role in plant reproduction because they transport pollen between various plants as they feed on nectar, transferring the pollen from the male part of plants to the female parts. This is particularly important to many fruits, especially commercially grown fruits such as apples, peaches, berries, melons, and nuts. Commercial honey bee operations (generally constituting thousands of hives) are responsible for pollinating 1/3 of the commercially produced crops in the United States. Commercial honey bee operations produce honey, beeswax, and hives are often rented to farmers for production. Smaller “backyard” honey bee operations (fewer than 100 hives) are used for honey production and to pollinate crops locally (Conrad 17). Native bees also play an important role in pollination (since they are native, they often have special adaptations to harvest nectar from native crops). However, due to habitat destruction, the populations of native bees and other pollinators like birds have decreased (Penn State 2009).


Causes

Despite numerous studies that have been conducted by private firms, universities, and the United States government, the exact cause (or, more likely, causes) behind CCD have yet to be identified. Suspected factors that have been investigated include immunodeficiency, pathogens, pesticides, physiological changes, mites, fungus, the use of antibiotics on hives by beekeepers, malnutrition, stress, the transportation of bees across long distances, and electromagnetic radiation (Chen, et. al 2009). Whether or not any of these suspects are the cause of CCD is still uncertain; however, recent studies have suggested that CCD could be caused in part by a combination of these and other factors (Chen, et. al 2009). It is probable, in other words, that CCD is the result of a synergistic action between various pesticides and herbicides, possibly along with various other factors such as physical stress and infection (Chen, et. al 2009).


BreannaBee

Microbial and Parasitic:

Some evidence suggests that certain microbial or parasitic life forms could be at least partly responsible for the skyrocketing incidence rate of CCD (Chen, et. al 2009). In some cases, hives that have suffered CCD have been found to have members infected with larger populations of microbial life forms than members of hives that are not impacted by CCD (Watanabe 2008). One parasite that has been known to devastate hives is the Varroa mite. This organism lives on the surface of the honey bee and feeds on the bee’s ‘blood,’ a substance called hemolymph (Watanabe 2008). Another deadly parasite that feeds on the hemolymph of honey bees is the tracheal mite, which clings to the adult bee’s breathing apparatus (Watanabe 2008). While attached to its host, this mite injects the bees with bacteria (Watanabe 2008). This contamination, combined with the weakening effects caused by the feeding of the mite, ultimately results in the death of the bee (Watanabe 2008). Two types of unicellular fungal parasites that could also be contributing to CCD are Noserna apis and Nosema ceranae (Watanabe 2008). These species infect and damage the bee’s digestive tract, making the bee vulnerable to various types of bacteria and viruses (Watanabe 2008). Infection by these fungi also reduces the lifespan of the bee (Watanabe 2008). While studies have not yet been able to identify any particular pathogen or parasite that is present in all collapsed colonies and could therefore be identified as a culprit behind CCD, CCD hives have been found to have greater numbers of bees infected with viruses than non-CCD hives (Chen, et. al 2009). Furthermore, hives that experience these higher incidence rates of infected members also experience a higher incidence rate of co-infection with multiple disease agents than non-CCD hives (Chen, et. al 2009).

Chemical:

Other possible causes include pesticides and herbicides used in and around bee hives, including pesticides used to kill Varroa mites. Studies, including one conducted by personnel from Penn State, have investigated the chemical residues from these substances in honey bee wax, pollen, nectar, and the bees themselves (Watanabe 2008). Over 170 chemicals were evaluated in the Penn State study, but no solid connections between CCD hives and these chemicals have been discovered (Watanabe 2008). True, CCD hives have been found to contain high levels of pesticides, but nothing that strongly indicates causality (Watanabe 2008).

Economic Analysis & Impacts

Economic Value of the Honey Bee:

The honey bee industry presents two main sources of economic value. First is the production of honey, wax, and other related products. Secondly and most importantly, honey bees are the only commercial pollinator. An estimated one-third of the human diet can be traced directly or indirectly to animal pollination. (Committee on the Status of Pollinators in North America, et al. 104). There are even some U.S. products, like almonds and five major fruits, which are completely dependant on commercial pollinators. (Adair 2007)


Honey bee colony owners try to strike a balance between their two sources of income: honey and wax production and commercial pollination. Crops that yield small amounts of honey are charged high pollination fees, but others that yield a large amount of honey are barely charged. Recorded prices have ranged from less than 3 dollars per colony to as much as 150 dollars per colony. Although pollination fee data are not reported nationally, the total has been estimated at $150 million: $75 per hive for each of the 2 million hives in commercial hands (Committee on the Status of Pollinators in North America, et al. 113-114). By far, the majority of income is brought in through pollination fees.


Scale and Scope of the Impact of Honey Bees as Pollinators:

Picture 1_1.ipg

(Chart: Committee on the Status of Pollinators in North America, et al. 106)

Although wild species are either known or likely to be important pollinators, the crops above are assumed to be dependant on commercial pollination.

Pollinator Shortages:

A “pollinator shortage” occurs when the demand for pollination is greater than the ability of pollinators, primarily honey bees, to transport pollen or supply pollination (Committee on the Status of Pollinators in North America, et al. 104). Even though it can be observed that a plant did not receive enough pollination, it is extremely difficult to prove that it was a pollinator shortage and not a pollen shortage. Even so, the effects of CCD are disputed. CCD decreases the number of available pollinators, but the impact is controversial.

CCD graph

Economic Consequences of Pollinator Shortages:

Predicting the short-run consequences of population decline of honey bees is not straightforward. The supply curve would shift leftward, representing the effect of CCD: a decrease in the availability of pollination transportation and a rise in cost of producing and maintaining commercial bees. At any price, the quantity of bees supplied would be reduced, which would constitute a negative economic impact.

Aside from the supply side impact of CCD, demand of pollination services has also changed. In the past decade, the population of the United States has grown by approximately ten percent, which translates to a ten percent increase in demand of food production. Some sources suggest that this translates to an additional 200,000 colonies of bees (Committee on the Status of Pollinators in North America, et al. 104) This causes a rightward shift of the demand curve.

When both the demand and supply shift, changes in quantity cannot be specified. A new long-run market equilibrium would be established with higher pollination fees that eventually would translate to higher prices at the supermarket. (Committee on the Status of Pollinators in North America, et al. 118-119)

(Graph: Committee on the Status of Pollinators in North America, et al. 115)


CCDfees graph

Is This Happening?:

Although much evidence is stipulated or questioned (Is there a pollinator shortage or a pollination shortage?), there is evidence that pollination fees are on the rise. All pollination price data recorded after 2005 show price spikes similar those of the almond and plum industry between 2004 and 2005 in the graph (Committee on the Status of Pollinators in North America, et al. 104-130). Rising production costs may prompt producers of pollination-dependent crops to exit the industry or to shift to crops that do not depend on pollinators. Either way, increases in pollination fees impact food costs.

The impact of CCD will not affect many crops like grains, rice, wheat, maize, or barley, which are self-pollinating or wind-pollinated (Committee on the Status of Pollinators in North America, et al. 105). Pollinator declines, in other words, are not a threat to the entire food supply, just to many fruits and vegetables, which provide essential nutrients. Nonetheless, pollinators are important because they contribute to genetic diversity.

(Graph: Committee on the Status of Pollinators in North America, et al. 117)

Potential Solutions/ Long-run Impact:

The long-term economic consequences of continued honey bee population decline will depend on how farmers, beekeepers, scientists, and others respond to smaller populations and higher fees. Many potential solutions follow the Neo-Classical approach.

Proposed Solutions Include:

1) Addressing the issue of insufficient cross-pollination through genetic alterations. For example, recently sunflowers and strawberries have been genetically altered to produce hermaphrodite flowers. Other varieties of fruit like bananas, pineapples, grapes, and cucumbers can produce without sexual fertilization through a process know as parthenocarpy. Both parthenocarpic fruit and hermaphrodite fruit solve the problem of insufficient pollinators by bypassing them altogether.(Committee on the Status of Pollinators in North America, et al. 112)

2) Changing plant arrangements in order to optimize pollination distribution is another proposed solution. Studies prove that in apple orchards, pollen distribution is almost limited exclusively to the nearest four trees (Committee on the Status of Pollinators in North America, et al. 112). This indicates that planting in rows lowers the efficiency of pollinators and a pollinator shortage may be created unnecessarily.

3) Questions have arisen as to whether or not there is pollinator limitation (insufficient pollinator service) or if there is pollen limitation (insufficient amounts of pollen). Increasing the availability of pollen is another proposed solution.

4) Alternative means of pollination have also been proposed. Hand-pollination, although tried in some countries, seems impractical. (Committee on the Status of Pollinators in North America, et al. 121) Other animals could potentially be used as commercial pollinators.

5) Lastly, but not as a primary solution, research has been focused directly on controlling mites as well as on bee tolerance of mites. (Committee on the Status of Pollinators in North America, et al. 118)

Potential Solutions

flowers CCD

Limits to Importation of Pollinators:

In 1922, congress passed a law that put strict restrictions on the importation of honey bees from abroad. This prevented potentially dangerous bees and diseases from reaching North America (Committee 2007) . In 2005, however, the almond industry lobbied to have the law repealed in order to accumulate more pollinators. Since then, an array of pests and diseases has entered the country that may be contributing to CCD. For example, the introduced protozoan parasites Nosema bombi and Crithidia bombi and Varroa mite are lethal to bees (Committee 2007) . The federal government needs to reinstate the stringency of the 1922 law and expand its contents to include the regulation of all managed pollinator species to ensure that more pests are not introduced.

Limit Monoculture Growing Practices:

Large monoculture crop fields do not occur naturally. With the dearth of plant diversity in such a field, bees and other pollinators face limitations to the breath of their diets. As more monoculture fields and lawns spread across suburbia without naturally occurring flowering weeds, bees are losing the full range of their diets. This could be leading to malnourishment in the bees (Cox-Foster 2009) . Planting a variety of flowers around crop fields or avoiding monoculture crop fields all together will help remedy this problem.



Genetic Modification:

As introduced diseases such as IAPV continue to infect bee populations, one way to buffer bee populations would be to have beekeepers and scientists make a conscious effort to breed virus-resistant bees (Cox-Foster 2009) . Recently the honey bee genome has been decoded and can now serve as a tool for choosing bees with genetic superiority. This tactic could take years, unfortunately, and may not produce results fast enough to mitigate the economic damage done to beekeepers going out of business.

Best Management Practices:

Finally, better pest and bee management practices are required to mitigate the risks of CCD. Integrated pest management techniques employing the use both natural and least-toxic synthetic pesticides for mite control must be developed. There is some promise in using pheromones as a natural pest manager. Furthermore, beekeepers should regularly sterilize their beehives with gamma rays to kill potential infectious agents (Cox-Foster 2009) .


Sources

Adair, Aly. Disappearing Bees Could Sting Our National Economy: Bee Keepers Call for Government Internvention.  YahooAssociatedContent.http://www.associatedcontent.com/article/211317/disappearing_honey_bees_could_sting.html?cat=17April 16, 2007. 1-2. 

Brackney, Susan. Plan Bee: Everything You Ever Wanted to Know About the Hardest Working Creatures on the Planet. Penguin Group, Inc.: London, 2009.

Buchmann, Stephen. Letters from the Hive: An Intimate History of Bees, Honey, and Humankind. Bantam Publishing: New York, 2005.

Chen, Yanping, Diana Cox-Foster, Jay D. Evans, Jim Frazier, Maryann Frazier, Eric Haubruge, Chris Mullin, Bach Kim Nguyen, Jeffery S. Pettis, Claude Saegerman, David R. Tarpy, Robyn Underwood, Dennis van Engelsdorp. 2009. Plos One. “Colony Collapse Disorder: A Descriptive Study.” http://www.plosone.org/article/info:doi/10.1371/journal.pone.0006481. (Accessed April 26, 2011).

Committee on the Status of Pollinators in North America, et al., The Status of Pollinators in North America. Washington, D.C.:  The national Academies Press, 2007.

Conrad, Ross. Natural Beekeeping: Organic Approaches to Modern Apiculture. Chelsea Green Publishing: Vermont, 2007.

Diana Cox-Foster and Dennis van Engelsdorp, “Solving the Mystery of the Vanishing Bees,” Scientific American, March 31 2009

Morse, Robert A. and Nicholas W. Calderone. “The Value of Honey Bees as Pollinators of U.S. Crops. Cornell University.  Ithaca, New York.  1-16.

Penn State College of Agricultural Sciences. Conserving Wild Bees in Pennsylvania. Pennsylvania State University Publishing: State College PA, 2009.

Watanabe, Myrna E. “Colony Collapse Disorder: Many Suspects, No Smoking Gun.” Bioscience 58 (2008): 384-388. http://ehis.ebscohost.com/eds/detail?sid=c8fddd47-189e4a80b53af6bee93ee40a%40sessionmgr104&vid=1&hid=121&bdata=JnNpdGU9ZWRzLWxpdmU%3d#db=a9h&AN=32209900. (Accessed April 26, 2011).


Photo Sources:

http://www.newmediaexplorer.org/sepp/2007/03/06/millions_of_bees_die_are_electromagnetic_signals_to_blame.htm

http://seeker401.wordpress.com/2010/06/13/mobile-phones-responsible-for-disappearance-of-honey-bees/

http://georgiabees.blogspot.com/2009/11/varroa-mites-on-honey-bees-treat.html

http://frederick.umd.edu/HorticultMasterGardener/index.cfm