The apparent recent invasion of Nosema ceranae and its dominance over Nosema apis in honey bee populations in the USA and elsewhere have presented both an enigma and a treatment problem for apiculturists and scientists. Several studies, including those of our research group, have shown that N. ceranae produces more mature spores than N. apis, and we demonstrated that reproduction of N. ceranae recovers more quickly from fumagillin treatment than does N. apis. In addition, N. ceranae hyperproliferated in the presence of very low fumagillin concentrations in laboratory bioassays. Proteomiclevel studies of fumagillin-N. ceranae-honey bee interactions continue and we are investigating the mechanisms of protein regulation in response to infection and fumagillin treatment. In studies of infectivity, we found that N. ceranae consistently has a higher IC50 than N. apis. The effect is most pronounced at 1 day post eclosion. We investigated the interaction of N. ceranae and N. apis in individual bees and found that N. apis produced more spores than N. ceranae in 62% of bees infected with equal dosages of both Nosema species. Mixed species infections negatively affected survival time (15-17 days) compared to single species infections (20 and 21 days for N. ceranae and N. apis, respectively) and uninfected bees (27 days). Midgut spore counts were higher for mixed species infections than for single species infections, but we did not find evidence that N. ceranae outcompetes N. apis in an individual host.
|Original language||English (US)|
|Title of host publication||2014 International Congress on Invertebrate Pathology and Microbial Control and 47th Annual Meeting of the Society for Invertebrate Pathology, August 3-7th, 2014, Mainz, Germany|
|State||Published - 2014|