Myrsini Natsopoulou said: “Our results reveal not only that the exotic parasite is a better competitor than its original close relative, but that its widespread distribution and patterns of prevalence in nature depend on climatic conditions too”.
The research compared pathogen growth in honey bees that were infected with both the exotic parasite, Nosema ceranae and its original native relative, Nosema apis. Experiments showed that, while both parasites inhibit each other’s growth, the exotic Nosema ceranae has a much greater negative impact on the native Nosema apis than vice versa. By integrating the effects of competition and climate into a simple mathematical model, the researchers were better able to predict the relative occurrence of both parasite species in nature: Nosema ceranae is common in Southern Europe but rare in Northern Europe.
Coauthor of the study, Prof. Robert Paxton of Queen’s University Belfast, added: “This emerging parasite is more susceptible to cold than its original close relative, possibly reflecting its presumed origin in East Asia. In the face of rising global temperatures, our findings suggest that it will increase in prevalence and potentially lead to increased honey bee colony losses in Britain.”
This study was funded by the German Federal Institute of Food and Agriculture and the UK Insect Pollinators Initiative.
Natsopoulou ME, McMahon DP, Doublet V, Bryden J, Paxton RJ. (2015) Interspecific competition in honey bee intracellular gut parasites is asymmetric and favours the spread of an emerging infectious disease. Proceedings of the Royal Society B: Biological Sciences. 20141896