Species Delimitation and Molecular Phylogenetics of South American Fire Ant Decapitating Flies (Diptera: Phoridae: Pseudacteon)

SANCHEZ RESTREPO, ANDRES; CHIFFLET LUCILA; CONFALONIERI VIVIANA A.; NEIL D. TSUTSUI; MARCOS ANTO NIO PESQUERO; CALCATERRA LUIS A.

PLOS ONE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2020 p. 1 - 13

1932-6203

South American fire ant decapitating flies in the genus Pseudacteon (Diptera: Phoridae) arepotential biocontrol agents of the invasive fire ants Solenopsis invicta and S. richteri in theUnited States and other regions of the world due to their high host specificity and the directand indirect damage to their host ants. Despite their importance and the fact that several flieshave already been released in the US, little is known about the genetic variability and phylogeneticrelationships of Pseudacteon flies parasitizing South American fire ants in the Solenopsissaevissima species-group. A species delimitation analysis was conducted using adistance-based method (ABGD) and two tree-based methods (GMYC and mPTP) using COIsequences of 103 specimens belonging to 20 of the 22 Pseudacteon species known fromsouthern South America. Additionally, phylogenetic relationships between the alreadydescribed and new candidate species were inferred using mitochondrial (COI) and nuclear(wingless) sequences. The species delimitation analysis suggests that species richness inthese flies has been previously underestimated, due to the existence of putative cryptic specieswithin nominal Pseudacteon obtusus, P. pradei, P. tricuspis, P. cultellatus, and P. nudicornis.Geographic distribution and host fire ant species seem to support cryptic lineages,though additional morphological data are needed to corroborate these results. All phylogeneticanalyses reveal that South American fire ant decapitating flies are grouped into two mainclades, with Pseudacteon convexicauda sister and well differentiated relative to these clades.Neither host nor geographic association appeared to be related to the differentiation of thesetwo main clades within South American fire ant decapitating flies. This work provides informationthat will allow testing whether the putative cryptic phorid fly species show differences intheir effectiveness as biocontrol agents against the highly invasive imported fire ants.