Protozoan and Fungal Diseases in Solenopsis richteri and S. quinquecuspis (Hymenoptera: formicidae) in Buenos Aires Province, Argentina

The diversity and abundance of protozoa and fungi infecting colonies of the fire ants Solenopsis richteri Forel and S. quinquecuspis Forel were surveyed in Buenos Aires province, Argentina. A total of 185 roadside sites was selected, and 1,836 colonies were sampled and examined under phase-contrast microscopy. Pathogens were found at 32% of the sites and in 10% of the colonies. The microsporidium Thelohania solenopsae Knell, Allen & Hazard was the most common microorganism; it was present at 25% of the sites and 8% of the colonies. In some sites within the surveyed region, the percentage of infected colonies with T. solenopsae ranged from 40 to 80%. Other pathogens present were the microsporidium Vairimorpha invictae Jouvenaz & Ellis and the fungus Myrmecomyces annellisae Jouvenaz & Kimbrough. A field site was selected for future ecological studies.