Speciation is the process through which reproductive isolation develops between distinct populations. Because this process takes time, speciation studies often necessarily examine populations within a species that are at various stages of divergence. The fall armyworm, Spodoptera frugiperda (J.E.Smith), is comprised of two strains (R=Rice & C=Corn) that serve as a novel system to explore population divergence in sympatry. Here, we use ddRADSeq data to show that fall armyworm strains in the field are largely...

An earlier version of this commentary was presented at the 2021 Union for Democratic Communications conference (held virtually, June 23-25) during the closing plenary, “A Return to Sut Jhally’s 2018 Dallas Smythe Keynote Address: Stuart Hall’s Legacy for Media Studies: Conjunctures, Critique, and Political Projects.”

Biodiversity of tropical grasslands and savannas (tropical grassy biomes; TGBs) remains poorly documented compared to tropical forests. This is in part due to the misplaced notion of TGBs being anthropogenic forest derivatives that support negligible biodiversity and endemism. For the Indian savannas, the legacy of colonial forestry has led to their misinterpretation as anthropogenic wastelands of low conservation value. One key assumption underlying the devaluation of Indian savannas against Indian forests is the presumed absence...

During IODP Expedition 382, two sites were drilled at 53.2°S at the northern edge of the Scotia Sea and three sites at 57.4°–59.4°S in the southern Scotia Sea within the Atlantic sector of the Southern Ocean. Sediments at both locations alternate between dominant terrigenous components during glacials and dominant biogenic components, carbonate at the northerly sites and opal in the southern Scotia Sea, during interglacials. Here we constrain the geochemical environment in interstitial waters using...

1. Patterns in, and the underlying dynamics of, species cooccurrence is of interest in many ecological applications. Unaccounted for, imperfect detection of the species can lead to misleading inferences about the nature and magnitude of any interaction. A range of different parameterisations have been published that could be used with the same fundamental modelling framework that accounts for imperfect detection, although each parameterisation has different advantages and disadvantages. 2. We propose a parameterisation based on...

Theory predicts that the strength of sexual selection (i.e., how well a trait predicts mating or fertilization success) should increase with population density, yet empirical support remains mixed. We explore how this discrepancy might reflect a disconnect between current theory and our understanding of the strategies individuals use to choose mates. We demonstrate that the density-dependence of sexual selection predicted by previous theory arises from the assumption that individuals automatically sample more potential mates at...

We investigated replicated ecological speciation in the livebearing fishes Poecilia mexicana and P. sulphuraria (Poeciliidae), which inhabit freshwater habitats and have also colonized multiple sulfidic springs in southern Mexico. These springs exhibit extreme hypoxia and high concentrations of hydrogen sulfide, which is lethal to most metazoans. We used phylogenetic analyses to test whether springs were independently colonized, performed phenotypic assessments of body and gill morphology variation to identify convergent patterns of trait differentiation, and conducted...

Nonrandom recruitment of parasites among hosts can lead to genetic differentiation among hosts and mating dynamics that promote inbreeding. It has been hypothesized that strictly aquatic parasites with intermediate hosts will behave as panmictic populations among hosts because ample opportunity exists for random mixing of unrelated individuals during transmission to the definitive host. A previous allozyme study on the marine trematode Lecithochirium fusiforme did not support this hypothesis in that there was genetic differentiation among,...

Understanding the processes by which species colonize and adapt to human habitats is particularly important in the case of disease-vectoring arthropods. The mosquito species Aedes aegypti, a major vector of dengue and yellow fever viruses, probably originated as a wild, zoophilic species in sub-Saharan Africa, where some populations still breed in tree holes in forested habitats. Many populations of the species, however, have evolved to thrive in human habitats and to bite humans. This includes...