Conservation, Research and Education Opportunities International

Analysis of virulence of the honey bee entomopathogen Nosema ceranae isolated from different geographic zones of Argentina and implications for honeybee conservation

M.P. Porrini 

Picture1This project focused on the parasitism by Nosema ceranae on honeybees in Argentina, including an analysis of virulence and the physiological effects of different strains isolated from different regions of the country. Apiculturists have enthusiastically collaborated with the study, providing samples across wide-ranging biogeographic areas of the country. This was achieved through a “National Survey of Nosemosis” campaign aimed at apiary producers and cooperatives. It is important to note that sample analysis was conducted free of cost to the apiculturists. To date, we have samples from approximately 250 hives from many different regions of the country.

Samples were analyzed individually under a microscope to determine presence of Nosema spp. spores, then subsampled for genetic analysis of species. Our results show that N. ceranae – a new species – has reached all regions of the country, independent of climatic or production characteristics. Interestingly, there was an absence of co-infections of both Nosema species, suggesting a possible displacement of N. apis (the historical parasite) by N. ceranae. This study provided the first documentations of the parasite for several provinces.

Virulence analysis was conducted by infecting bees in the lab using spores collected from three geographic zones: central (Buenos Aires Province), extreme north (Misiones Province) and south (Rio Negro Province). Preliminary results suggest that there is no difference between parasite development rates or in the survival of infected bees relative to spore origin. This supports the hypothesis that observed regional variation is due to differences in regional climate or apiculture practices.

 We have embarked on a massive outreach campaign, using online, print and radio media, as well as distributing a free flyer to disseminate our results to collaborators, apiculturists, governmental agencies and researchers. ($5,770)