CONICET | Buscador de Institutos y Recursos Humanos

With 40 years of history in Argentina and long-term studies restricted to a few host insect orders, Microsporidiology as a whole is still a young discipline in the country. Initial research was prompted by experimental use of the grasshopper biocontrol agent Paranosema locustae. Other sustained efforts studied microsporidia associated with black flies, mosquitoes, fire ants, and more recently with honey bees and bumble bees. Bumble bees (Bombus spp.) play a key role as highly efficient pollinators in a variety of natural and man-made ecosystems. Of the approximately 250 species known worldwide only nine native species have been reported to inhabit Argentina, Chile, and Uruguay which seem to depict a somewhat low diversity for southern South America when compared to the Palearctic and Nearctic regions. Two additional Palearctic species were introduced late in the XX century in Chile, became naturalized, and spread to Argentina across the southern Andes. Less than a decade ago knowledge of microsporidia associated with bumble bees in the southern Neotropic was nonexistent. Since then surveys started and the occurrence of at least three microsporidia was recorded. The predominantly fat tissue pathogen Tubulinosema pampeana was discovered in native Bombus atratus and B. bellicosus in the Pampas, the enteric Nosema ceranae was registered in natives B. atratus, B. bellicosus, B. morio and B. brasiliensis in the Pampas and North of the country, and systemic Nosema bombi in exotics B. terrestris and B. ruderatus in western Patagonia. Since B. terrestris is extremely ubiquitous and has already reached the northern Patagonian Atlantic coast it is likely that its range expansion will continue further possibly allowing new microsporidia-host associations of unpredictable outcomes. The presentation will review the status of both microsporidia and hosts, emphasizing the importance of immediate intensification of surveys before B. terrestris reaches a wider distribution.