1. An Analysis of Possible Causes
of Worldwide
Honey bee (Apis mellifera L.)
Decline
Jonathan Spence

2. The honey bee (Apis mellifera L.)
• What is a honey bee?
-A stinging insect that collects nectar and pollen
- Most notable for it’s ability to make honey
- Honey bee hive consist of workers, drones, and a queen.
- Up to 60,000 honey bees in a single hive

3. Why are honey bees important?
• Honey bees contribute 10-33 billion dollars annually to the United
States economy.
• Honey bees are responsible for about 80% of total pollinating
insects of major crops.
• Agriculture
- Almonds, apples, avocados, blueberries, cranberries, cherries, kiwi fruit, macadamia nuts,
asparagus, broccoli, carrots, cauliflower, celery, cucumbers, onions, legume seeds, pumpkins,
squash, and sunflowers are 90%-100% dependent on honey bee pollination.
• Important for ecosystem

4. History of Declines
• From 1947-2005 a decrease from about 6 million hives to 2.5
million
Figure 1. U.S. honey bee colonies, 1945–2005. Data compiled from USDA-NASS

5. Figure 2. Bar graph representing losses from 2006-2015 annually. Bar graph
represents accepted annual loss, winter loss, and total annual loss. (Steinhauer et al.
2015)
• From 2006-2015 an
average of 28.7% loss
annually
• Highest annual loss seen
in 2012/2013 of 45%
• 2014/2015 a loss of
about 43% annual loss
• Personally lost 40% of
hives in 2015/2016
• Above acceptable rate of
about 15% annually

6. What could be causing honey bee declines?
Three potential reasons:
1. Pesticides
2. Mites
3. Viruses

7. Pesticides
• Pesticide- a substance used for killing/repelling insects
• Honey bees can be exposed:
- If present at time of application
- By nectar and/or pollen
• Honey bees bring pesticides back to hive

8. Pesticides found in hive
• Mullin et al. (2010) found that on average there are:
- Samples taken from 23 states and one Canadian province
totaling 887 beehives sampled
-60% of wax and pollen samples had at least one pesticide
- An average of 7 pesticides found in pollen samples
- Honey bees generally have lower pesticide levels

9. Affects of Pesticides on
Honey Bees
• Han et al. (2010) conducted research to
see how pesticides affect honey bees
• Placed honey bees in T-tube maze that
was color coded and had sucrose on one
side
- Blue used to test learning capability.
- Attracted to smell of sucrose
- Exposed for 7 days prior to test

10. • Only about 40% of pesticide exposed honey bees made the correct
decision. N=80 per session
• Decrease foraging efficiency could ultimately be the cause of a
decline in hive populations
• Decrease in visual and smell
learning capacities
Findings of Han et al. (2010)

11. Mites
• Two types
1. Varroa mites (Varroa destructor)
2. Tracheal mites (Acarapis woodi)
-Ectoparsites
- Same family as ticks
-Can live off all honey bees

12. Varroa mite
• Found worldwide
• Known to be main cause of honey bee colony collapse worldwide
• Out of 400 colonies sampled in Ontario Canada 75% were infested
• Leading cause of colony deaths from samples taken in Ontario
Canada
- more than 85%

13. Tracheal mite
• Lives inside of honey bee until mature
• Can affect honey bees ability to thermoregulate
• Can cause flight muscles to deteriorate
• Not as common
• Can vector viruses

14. Viruses
• sacbrood virus (SBV)
• chronic bee paralysis virus (CBPV)
• black queen cell virus (BQCV)
• deformed wing virus (DWV)
• acute bee paralysis virus (ABPV)
• kashmir bee virus (KBV)
• No vaccines or medications are available for any of the honey bee
viruses

15. Viruses
• Most common viruses found
- BQCV 30%- 85%
- DWV 80%-91%
Honey bee with DWV
Healthy Honey bee

17. Overall Findings
• Pesticides found in hives and can affect honey bees ability to
forage
• Varroa mites found in more than 75% of hive samples and are
known to be the main cause of colony collapses.
• Tracheal mites not as common but cause increased winter losses
by limiting the honey bees ability to thermoregulate
• BQCV and DWV were the most prevalent viruses
• Combination of all factors causing declines

18. What can be done?
• Get involved! Get a honey bee hive
• Educate beekeepers on what is causing honey bee declines and
what they can do to prevent losing colonies
• Funding for beekeepers and those wanting to become beekeepers
- currently cost about $500.00 to get started in beekeeping. Only 1 hive
• Limit use of pesticides, research pesticides that are less harmful
• Focus research on other honey bee species that could better
combat causes of honey bee declines.

19. Literature cited
• Arena, M., and F. Sgolastra. 2014. A meta-analysis comparing the sensitivity of bees to pesticides. Ectoxicology 23:324-334.
• Berenyi, O., T. Bakonyi, I. Derakhshifar, H. Koglberger, and N. Nowotny. 2006. Occurrence of six honeybee viruses in diseased Austrian apiaries.
Applied and Environmental Microbiology. 72:2414-2420.
• Chen, Y.P., J.S. Pettis, M. Corona, W. Ping Chen, C. Jun Li, M. Spivak, P.K. Visscher, G. DeGrandi-Hoffman, H. Boncristiani, Y. Zhao, D. vanEngelsdorp, K.
Delaplane, L. Solter, F. Drummond, M. Kramer, W.I. Lipkin, G. Palacios, M.C. Hamilton, B. Smith, S. Kang Huang, H. Qing Zheng, J. Lian Li, X. Zhang, A.
Fen Zhou, L. You Wu, J. Zhong Zhou, M.L. Lee, E.W. Teixeira, Z. Guo Li, and J.D. Evans. 2014. Israeli Acute Paralysis Virus: Epidemiology, Pathogenesis
and Implications for Honey Bee Health. PLOS Pathogens 10: 1-15.
• Christopher, A.M., M. Frazier, J.L. Frazier, S. Ashcraft, R. Simonds, D. vanEnglsdorp and J.S. Pettis. 2010. High Levels of Miticides and Agrochemicals in
North American Apiaries: Implications for Honey Bee Health. PLOSOne 5:1-19.
• Cornman, R.S., D.R. Tarpy, Y. Chen, L. Jeffreys, D. Lopez, J.S. Pettis, D. vanEngelsorp, and J.D. Evans.2012. Pathogen Webs in Collapsing Honey Bee
Colonies. PLOSOne 7:1-15.
• Genersch, E. 2010. Honey bee pathology: current threats to honey bees and beekeeping. Appl Microbiol Biotechnol. 87:87-97.
• Han, P., C.Y. Niu, C.L. Lei, J.J. Cui, and N. Desneux. 2010. Use of an innovative T-tube maze assay and the proboscis extension response assay to assess
sublethal effects of GM products and pesticides on learning capacity of the honey bee Apis mellifera L. Ecotoxicology 19:1612-1619.
• Highfield. A.C., A.E. Nagar, L.C.M. Mackinder, M. Laure, J. Noel, M.J. Hall, S.J. Martin, and D.C. Schroeder. 2009. Deformed wing virus implicated in
overwintering honey bee colony losses. Applied and Environmental Microbiology. 75:7212-7220.
• Johnson, R. 2010. Honey Bee Colony Collapse Disorder. Congressional Research Service 1-17.
• Johnson, R.M., M.D Ellis, C.A. Mullin, and M. Frazier. 2010. Pesticides and honey bee toxicity- USA. Apidologie 41:312-331.
• Kojima, Y., T. Toki, T. Morimoto, M. Yoshiyama, K. Kimura, and T. Kadowaki. 2011. Infestation of Japanese native honey bees by tracheal mite and virus
non-native European honey bees in Japan. Microb Ecol. 62:895-906.

20. • McMullan, J.B., and M.J. Brown. 2009. A qualitative model of mortality in honey bee (Apis melliffera) colonies infested with tracheal mites. Exp Appl
Acarol. 47:225-234.
• Moore, P.A., M.E. Wilson, and J.A. 2015. Skinner. Honey bee viruses, the deadly varroa mite associates. Bee Health. 1-12.
• Mullin, C.A., M. Frazier, J.L. Frazier, S. Ashcraft, R. Simonds, D. vanEngelsdorp, and J.S. Pettis. 2010. High levels of miticides and agrochemicals in North
America apiaries: Implications for honey bee health. PLOSone 5:1-19.
• Pettis, J.S., D. vanEngelsddorp, J. Johnson, and G. Dively. 2012. Pesticide exposure in honey bees results in increased levels of the gut pathogen Nosema.
Naturwissenschaften 99:153-158.
• Pettis, J.S., R. Rose, E.M. Lichtenberg, P. Chantawannakul, N. Buawangpong, W. Somana, P. Sukumalanand, and D. vanEngelsdorp. 2013. A Rapid Survey
Technique for Tropilaelaps Mite (Mesostigmata: Laelapidae) Detection. Apiculture and Social Insects 106: 1535-1544.
• Rose, R., J. Pettis, K. Rennich, and D. vanEngelsdorp. A US national survey of honey-bee pests and diseases. (Journal, volume not specified) 1-4.
• Rycke, P.H., J.J. Joubert, S.H. Hosseinian, and F.J. Jacobs. 2002. The possible role of Varroa destructor in the spreading of American foulbrood among
apiaries. Experimental and Applied Acarology. 27:313-318.
• Singh, R., A.L. Levitt, E.G. Rajotte, E.C. Holmes, N. Ostiguy, D. vanEngelsdorp, W.I. Lipkin, C.W. dePamphilis, A. L. Toth, and D.L. Cox-Foster. RNA Viruses in
Hymenopteran Pollinators: Evidence of Inter-Taxa Virus Transmission via Pollen and Potential Impact on Non-Apis Hymenopteran Species. 2010. PLOS
One 5:1-16.
• Steinhauer, N., K. Rennich, K. Lee, J. Pettis, D.R. Tarpy, J. Rangel, D. Caron, R. Sagili, J.A. Skinner, M.E. Wilson, J.T. Wilkes, K.S. Delaplane, R. Rose, and D.
vanEngelsdorp. 2015. Colony loss 2014-2015: Preliminary results. Bee Informed Partnership. 1-5
• vanEngelsdorp, D., J.D. Evans, C. Saegerman, C. Mullin, E. Haubruge, B.K. Nguyen, M. Frazier, J. Frazier, D. Cox-Foster, Y. Chen, R. Underwood, D.R. Tarpy,
and J.S. Pettis. 2009. Colony Collapse Disorder: A Descriptive Study. PLOS ONE 4:1-17.
• vanEngelsdorp, D., N. Speybroeck, J.D. Evans, B. Kim Nguyen, C. Mullin, M. Frazier, J. Frazier, D. Cox-Foster, Y. Chen, D.R. Tarpy, E. Haubruge, J.S. Pettis,
and C. Saegerman. 2010. Weighing Risk Factors Associated With Bee Colony Collapse Disorder by Classification and Regression Tree Analysis. J. Econ.
Entomol. 103:1517-1523.

21. Thanks to…
• Dr. Pearson
• Dr. Rockel
• Dr. Soper Gorden
• Mitchell Blackmon
• Megan Maddox

22. Questions?