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United States Department of Agriculture

Agricultural Research Service


Location: Imported Fire Ant and Household Insects Research

Title: Kneallhazia carolinensae sp. nov., a microsporidian pathogen of the thief ant, Solenopsis carolinensis

item Valles, Steven
item Becnel, James
item Pereira, Roberto

Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/27/2011
Publication Date: 9/1/2011
Publication URL:
Citation: Valles, S.M., Becnel, J.J., Pereira, R.M. 2011. Kneallhazia carolinensae sp. nov., a microsporidian pathogen of the thief ant, Solenopsis carolinensis. Journal of Invertebrate Pathology. 108:59-62.

Interpretive Summary: Microsporidia are unicellular pathogens of fungal origin often used as biological control agents to control insect populations. Kneallhazia solenopsae is a microsporidian used to control the red imported fire ant. This ant currently infests about 300 million acres and causes economic losses that exceed 6 billion dollars annually in the United States. In an attempt to discover new microsporidia to control fire ants, scientists at the USDA-ARS, Center for Medical, Agricultural and Veterinary Entomology (Gainesville, FL) and the University of Florida, have identified and described a new species of Kneallhazia found in a related ant, Solenopsis carolinensis. This microsporidian is only the second species identified in this genus (Kneallhazia) and may provide additional clues about the biology of these organisms, especially as it pertains to pathogenesis, which may lead to improved biological control techniques for fire ants.

Technical Abstract: A new species of microsporidia is described from adults of the thief ant, Solenopsis carolinensis, collected in Florida, USA. Morphological and genetic characterization of this new species showed that it is most closely related to the genus Kneallhazia and is therefore formally designated, Kneallhazia carolinensae sp. nov. Only ovoid binucleate spores were observed that measured 6.19 ±0.115 x 3.05 ± 0.069 µm (fresh) and 5.96 ±0.139 x 3.44 ± 0.088 µm (fixed). These spores were in direct contact with the cell cytoplasm and contained an isofilar polar filament that contained 12-15 coils. Blast-n analysis revealed that the K. carolinensae 16S rDNA sequence exhibited 91% identity with the 16S rDNA gene of K. solenopsae. The morphological and sequence data support the conclusion that K. carolinensae is a novel microsporidian species distinct from K. solenopsae.

Last Modified: 10/17/2017
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