330 likes | 830 Views
Outline for today's talk. Background information a. Colony Collapse Disorderb. Nosema disease - hungerc. Risk-sensitive Foraging TheoryCompleted researchProposed researchConcluding thoughtsCollaborative project proposal. Nosema ceranae (400x). Colony Collapse Disorder (CCD). Not the first time
E N D
1. Energetic stress as a potential cause of colony collapse disorder Christopher Mayack
Department of Biology, Colorado State University
Presented on March 25th 2009
3. Colony Collapse Disorder (CCD)
Not the first time – since 1800’s
(Underwood 2008)
Parasites – N. ceranae
(Higes et al. 2008)
Pesticides - neonicotinoids
(Aliouane et al. 2009)
Nutrition - carbohydrates
(Mayack and Naug 2009)
4. Nosema apis and Nosema ceranae Widespread microsporidian gut parasite of the honeybee
N. ceranae recently jumped hosts from Apis cerana
5. Nosema apis and N. cerenae pathology Symptoms caused by lack of protein absorption
Symptoms
dysentery
reduction in hypopharengeal gland
accelerated age polyetheism
cuts honeybee life-span in half
foraging in poor weather conditions
6. Nosema infection and its relation to hunger
7. What is Risk-sensitivity Theory? Foraging animals have to make decisions
Charnov’s classical Optimal Foraging Theory
Homogenous food patches were assumed
8. Empirical evidence for risk-sensitivity theory Fish, mammals, and insects do not follow Charnov’s (1976b) model
They exhibit risk-sensitive foraging
9. Energy-budget Rule
Positive energy budget
Risk-averse
Negative energy budget
Risk-prone
10. Risk-sensitive foraging in bumble bees Switched from risk-averse to risk-prone with energy budget manipulation
Different food storage in comparison to honeybees
Energy reserves – based on colony food stores
11. Risk-sensitive foraging in honeybees Studies have shown honeybees are risk-indifferent
store food
communicate the location of food sources
colony needs versus individual needs
12. Connecting the dots: overview
13. Study Objectives Nosema causes an increase in hunger, appetite, and lowers survival
Demonstrate that hungry bees exhibit risk-prone behavior
Dissociate individual hunger from social hunger
14. Hypothesis 1 Nosema ceranae causes an increase in hunger, appetite, and lowers survival.
15. Summer of 2008
Monitored colonies for infection at two field sites
Collected foragers
Assayed infection with a hemacytometer
16. Setup of all three experiments
17. Measuring appetite Proboscis Extension Response (PER)
Responsiveness test
0.1, 0.3, 1, 3, 10, 30%
sucrose solution
18. Do infected foragers havea larger appetite?
19. Measuring the hunger levelof foragers Data recorded at 6 hour intervals
for 24 hours
Amount of 30% sucrose solution consumed over 24 hours
20. Are infected foragers hungrier than non-infected ones?
21. Monitoring survival of infected and uninfected foragers Data recorded at 6 hour intervals for 24 hours
Feed each honeybee given amounts of
30 % sucrose solution in 5 µl, 10 µl, 20 µl, 30 µl amounts
Survival and body temperature were recorded
22. Can infected foragers surviveas well as uninfected foragers?
23. Should hungry individuals be risk-prone?
24. Summary of results – Project 1 N. ceranae increases appetite and hunger in infected honeybees
N. ceranae decreases survival rate of infected individuals
Infected hungry individuals on a negative energy budget are likely to exhibit risk-prone behavior
25. Demonstrating risk-prone behavior – Project 2 set up
26. What we plan on seeing…
27. Dissociate individual hunger from social hunger– Project 3
28. Recording the artificial flower visits within one foraging bout
After forager is trained to the bee-board
Color preference will be recorded
29. Are hungry individualsin a satiated colony risk-prone?
30. Take Home Messages Nosema infection causes energetic stress in honeybees
Energetically stressed honeybees prefer the risky, variable food source
At risk of
Starvation
Hypothermia
31. Future Directions See if this risk-prone behavior is occurring out in the field
Find ways to prevent forager starvation or hypothermia
32. Fingers are pointing to Nosema ceranae Higes et al. (2008, 2009) demonstrated collapse with Nosema ceranae
Has found dead foragers out away from the hive that are highly infected
No evidence of pesticides
33. Collaborative Project Proposal 1. Prevent Hypothermia
34. Overall Plan – Lets Work Together I would like to start Fall of 2009
For funding I am applying to a project Apis m. grant
I am hoping to get 30 or more volunteer beekeepers
35. Set up, Materials, and Logistics Around 2 infected colonies from each volunteer
To screen for infected colonies we can use one of the teaching lab rooms at Colorado State University
I will train you on how to screen your hives for Nosema, this will take one day in the Fall of 2009
36. Monitoring colony populations Using a metal grid sample the bottom box 10 frames of bees, both sides
Bees that take up a half square or more will count as 1 square.
If weather does not permit for opening a hive I do not expect to collect data for these months
37. Details on the two treatments
38. Projected Results
39. Concluding Thoughts This would provide beekeepers a cheap feasible alternative to fumagillin
Nosema may become resistant to fumagillin
Increased hunger due to infection is a general mechanism and this may not only apply to Nosema, but to other infections as well
41. References Aliouane, Y., et al., 2009. Subchronic exposure of honeybees to sublethal doses of pesticides: effects on behavior. Environmental Toxicology and Chemistry. 28, 113-122.
Barnard, C. J. & Brown, C. A. J. 1985. Risk sensitive foraging in common shrews (Sorex araneus L.). Behavioral Ecological and Sociobiology, 16, 161-164.
Caraco, T., Martindale, S. & Whittam, T. S. 1980. An empirical demonstration of risk sensitive foraging preferences. Animal Behaviour, 28, 820-830.
Cartar, R. V. 1991. A Test of Risk-Sensitive Foraging in Wild Bumble Bees. Ecology, 72, 888-895.
Charnov, E. L. 1976a. Optimal foraging: Attack strategy of a mantid. American Naturalist, 110, 141-151.
Charnov, E. L. 1976b. Optimal foraging: The marginal value theorem. Theoretical Population Biology, 9, 129-136.
von Frisch, K. 1967. The Dance Language and Orientation of Bees. Cambridge, Massachusetts: Belknap Press.
Hassanein, M. H. 1953. The influence of infection with Nosema Apis on the activities and longevity of the worker honeybee. Analytical Application of Biology, 40, 418-423.
Higes, M., et al., 2009. Honeybee colony collapse due to Nosema ceranae in professional apiaries. Environmental Microbiology Reports. In Press.
Higes, M., et al., 2008. How natural infection by Nosema ceranae causes honeybee colony collapse. Environmental Microbiology. 10, 2659-2669.
Kacelnik, A. & Bateson, M. 1997. Risk-sensitivity: crossroads for theories of decision-making. Trends in Cognitive Sciences, 1, 304-309.
Liu, T. P. 1984. Ultrastructure of the midgut of the worker honey bee Apis mellifera heavily infected with Nosema apis. Journal of Invertebrate Pathology, 44, 282-291.
42. References cont. Malone, L. A. & Gatehouse (nee Edmonds), H. S. 1998. Effects of Nosema apis infection on honey bee (Apis mellifera) digestive proteolytic enzyme activity. Journal of Invertebrate Pathology, 71, 169-174.
Mattila, H. R. & Otis, G. W. 2006. Effects of Pollen Availability and Nosema Infection During the Spring on Division of Labor and Survival of Worker Honey Bees (Hymenoptera: Apidae). Environmental Entomology, 35, 708-717.
Mayack, C., Naug, D., 2009. Energetic stress in the honeybee Apis mellifera from Nosema ceranae infection. Journal of Invertebrate Pathology. In Press.
Moffet, J. O. & Lawson, F. A. 1975. Effect of Nosema-Infection on O2 Consumption by Honey Bees. Journal of Economic Entomology, 68, 627-629.
Page Jr., R. E., Erber, J. & Fondrk, M. K. 1998. The effect of genotype on response thresholds to sucrose and foraging behavior of honey bees (Apis mellifera L.). Journal of Comparative Physiology A, 182, 489-500.
Real, L. A. 1981. Uncertainty and pollinator-plant interactions: the foraging behavior of bees and wasps on artificial flowers. Ecology, 62, 20-26.
Shafir, S., Wiegmann, D. D., Smith, B. H. & Real, L. A. 1999. Risk-sensitive foraging: choice behavious of honeybees in response to variability in volume of reward. Animal Behaviour, 57, 1055-1061.
Shafir, S., Menda, G. & Smith, B. H. 2005. Caste-specific differences in risk sensitivity in honeybees, Apis mellifera. Animal Behaviour, 69, 859-868.
Stephens, D. W. & Krebs, J. R. 1986. Foraging Theory. Princeton: Princeton University Press.
Underwood, R., VanEngelsdorp, D., 2008. Colony Collapse Disorder: Have We Seen This Before? Bee Culture. In Press.
White, G. F. 1919. Nosema disease. Bulletin of the U.S. Department of Agriculture, 1-59.
Young, R. J., Clayton, H. & Barnard, C. J. 1990. Risk sensitive foraging in bitterlings, Rhodeus sericus: Effects of food requirement and breeding site quality. Animal Behaviour, 40, 288-297.
43. Picture Websites & References mainstusa.blogspot.com
Higes et al. 2009
Springer Life Sciences
www.geocities.com
bumbleboosters.unl.edu
www.foxnews.com
chat.carleton.ca
http://1.bp.blogspot.com/_uic7-mrnqss/SHFwXObRIzI/AAAAAAAAAFA/9NrjMLxA5UI/s400/DSC00634.JPG
http://s3.amazonaws.com/pixmac-preview/businessmans-hand-pointing-finger-1.jpg
http://laurablood.files.wordpress.com/2008/05/honey-bee.jpg