Closeup of the head to Solenopsis geminata (fire ant)

Joint Evolution of Asexuality and Queen Number in an Ant

A recent paper in Current Biology by DeWayne Shoemaker and colleagues from the University of Georgia describes a socially polymorphic population of the tropical fire ant, Solenopsis geminata, in which multi-queen colonies produce queens asexually but produce workers sexually via matings with males from the sexually reproducing single-queen social form. Two distinct asexual lineages from multi-queen colonies likely originated from the same sexual single-queen population. Multiple asexual/polygyne genomes are transmitted undiluted in this system, but sterile workers produced with sperm from a sexually-reproducing/monogyne population are necessary for the persistence of these lineages. The intersection of social polymorphism, facultative asexuality, and genetic caste determination marks this population of S. geminata as an embodiment of the diversity of ant reproductive systems and suggests previously

Close-up of a fire ant; note the large head and mandibles

Recent Article: Sociometry of Solenopsis Geminata Reveals Variation in Colony-Level Phenotypes in Fire Ants

Abstract: In social insects, natural selection operates at the level of the colony, rather than the individual, but our understanding of how colony-level phenotypes arise and vary between species is lacking. Here, we test how colony-level phenotypes vary within the fire ants by measuring the composition of colonies of the tropical fire ant, Solenopsis geminata, over a wide range of sizes at multiple times throughout the year. Similar to the well-studied fire ant species S. invicta, we find that S. geminata colony composition varies strongly with colony size, such that as colonies grow they produce increasingly large workers as well as queens and males. However, major production increases more rapidly with colony size in S. geminata than in S. invicta,

North American fire ants surround and protect their significantly much larger queen

New Genetic Study Reveals Cryptic Diversity in the Native North American Fire Ants

The native North American fire ants (Solenopsis Westwood) comprise a difficult group taxonomically that has undergone multiple revisions in the past century yet remains in a state of taxonomic uncertainty. The results of our genetic study demonstrated that the recognised North American fire ant species represent evolutionarily independent entities. We also confirm the presumed sister status of the desert fire ants, S. aurea Wheeler and S. amblychila Wheeler. However, we also found tat least two genetically divergent populations within the nominal species boundaries, including a western form of S. xyloni and a distinct population of S. aurea. These results suggest that the current taxonomy does not fully capture the species‐level diversity in this group. Our study provides the molecular foundation for