Indirect genetic effects describe phenotypic variation that results from differences in the genotypic composition of social partners. Such effects represent heritable sources of environmental variation in eusocial organisms because individuals are typically reared by their siblings. In the fire ant Solenopsis invicta , a social supergene exhibits striking indirect genetic effects on worker regulation of colony queen number, su...

The fire ant Solenopsis invicta and its close relatives are highly invasive. Enhanced social cooperation may facilitate invasiveness in these and other invasive ant species. We investigated whether invasiveness in Solenopsis fire ants was accompanied by positive selection on sociobiological traits by applying a phylogenomics approach to infer ancient selection, and a population genomics approach to infer recent and ongoing sel...

Biological invasions are largely thought to be contemporary, having recently increased sharply in the wake of globalization. However, human commerce had already become global by the mid‐16th century when the Spanish connected the New World with Europe and Asia via their Manila galleon and West Indies trade routes. We use genetic data to trace the global invasion of one of the world's most widespread and invasive pest ants, the...

Landscape corridors are commonly used to mitigate negative effects of habitat fragmentation, but concerns persist that they may facilitate the spread of invasive species. In a replicated landscape experiment of open habitat, we measured effects of corridors on the invasive fire ant, Solenopsis invicta , and native ants. Fire ants have two social forms: polygyne, which tend to disperse poorly but establish at high densities, an...

Reproductive and worker division of labour ( DOL ) is a hallmark of social insect societies. Despite a long‐standing interest in worker DOL , the molecular mechanisms regulating this process have only been investigated in detail in honey bees, and little is known about the regulatory mechanisms operating in other social insects. In the fire ant Solenopsis invicta , one of the most studied ant species, workers are permanently s...

Transcriptome analysis is a powerful tool for unveiling the distribution and magnitude of genetic incompatibilities between hybridizing taxa. The nature of such incompatibilities is closely associated with the evolutionary histories of the parental species and may differ across tissues and between the sexes. In eusocial insects, the presence of castes that experience divergent selection regimes may result in additional distinc...

We characterized patterns of genetic variation in populations of the fire ant Solenopsis invicta in China using mitochondrial DNA sequences and nuclear microsatellite loci to test predictions as to how propagule pressure and subsequent dispersal following establishment jointly shape the invasion success of this ant in this recently invaded area. Fire ants in Wuchuan (Guangdong Province) are genetically differentiated from thos...

The taxonomy of fire ants has been plagued by difficulties in recognizing species on the basis of morphological characters. We surveyed allozyme markers and sequences of the mtDNA COI gene in several closely related nominal species from two areas of sympatry in the native ranges to learn whether the morphology‐based delimitation of these species is supported by genetic data. We found that Solenopsis invicta and Solenopsis rich...

One possible mechanism for interspecific transfer of Wolbachia is through the intimate contact between parasites and their hosts. We surveyed 10 species of fly parasitoids ( Pseudacteon spp.) and one inquiline social parasite, Solenopsis daguerrei , for the presence and sequence identity ( wsp gene) of Wolbachia . Two Wolbachia variants infecting S. daguerrei were identical to known variants infecting the two common ant host s...

Wolbachia are endosymbiotic bacteria that infect arthropods. As they are maternally transmitted, the spread of Wolbachia variants within host populations may affect host mtDNA evolution. We sequenced a portion of the mitochondrial cytochrome oxidase I gene from numerous individuals of two Wolbachia ‐infected fire ant species, Solenopsis invicta and S. richteri , to determine how these bacteria influence patterns of mtDNA varia...

Little is known about what determines patterns of host association of horizontally transmitted parasites over evolutionary timescales. We examine the evolution of associations between mushroom‐feeding Drosophila flies (Diptera: Drosophilidae), particularly in the quinaria and testacea species groups, and their horizontally transmitted Howardula nematode parasites (Tylenchida: Allantonematidae). Howardula species were identifie...