How honey bees (Apis mellifera L.) respond to infection with Nosema ceranae and Lotmaria passim

• Author / Creator

  MacInnis, Courtney I

• Nosema ceranae and Lotmaria passim are two commonly encountered digestive tract parasites of the Western honey bee (Apis mellifera L.) that have been associated with colony losses in Canada, the United States, and Europe. Though honey bees can be co-infected with these parasites, little is known about how they affect bee survival, behaviour, or physiology at both the individual and colony level. Using locally-isolated parasite strains, I evaluated the effects of single and co-infections on individual bee survival, responsiveness to sucrose, and the humoral defense response, while at the colony level, I evaluated the effect of these infections on honey bee foraging behaviour and vitellogenin (vg) expression. Results of the survival and sucrose responsiveness experiments showed that infection in general had a significant negative effect on bee survival and also increased bee responsiveness to sucrose, which could correspond to higher levels of hunger and energetic stress. The humoral defense response experiment illustrated that individual bees do not respond locally to infection with N. ceranae and L. passim, as monitored by the three antimicrobial peptides quantified. At the colony level, I found that at the first instance of foraging, bees that had either single or co-infections had significantly lower vg expression than uninfected bees, with co-infected bees having the lowest vg expression. I also found that co-infected bees had a significantly younger average foraging age (0.6 days) compared to uninfected bees from the same cohort. Collectively, the results of this thesis indicate that single and co-infections involving N. ceranae and L. passim can negatively affect individual honey bee lifespan, as well as behaviour and physiology, both at the individual and colony level. Changes in behaviour and physiology at the colony level are of great concern as these changes could result in smaller, less productive colonies, decreased colony survivorship, and reduced income for beekeepers. Because of this, routine monitoring should be undertaken for L. passim, and continue for N. ceranae, coupled with investigations of novel parasite management strategies.

• Subjects / Keywords

  • Apis mellifera
  • Lotmaria passim
  • Nosema ceranae
  • behaviour
  • physiology
  • parasitism
  • co-infections

• Graduation date

  Fall 2024

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/r3-6pa2-d452

• License

  This thesis is made available by the University of Alberta Library with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.