Species coexistence is shaped by a range of biotic and abiotic factors. Beyond predation, parasitism and competition, one species may interfere with another's reproduction to induce sexual exclusion from a habitat. Here, we test for reproductive interference from inter‐species mating between sympatric nematodes Caenorhabditis macrosperma and C. nouraguensis . Higher intrinsic population growth of C. nouraguensis arises from gr...

Understanding the plasticity, robustness and modularity of transcriptome expression to genetic and environmental conditions is crucial to deciphering how organisms adapt in nature. To test how genome architecture influences transcriptome profiles, we quantified expression responses for distinct temperature‐adapted genotypes of the nematode Caenorhabditis briggsae when exposed to chronic temperature stresses throughout developm...

Speciation genetics research in diverse organisms shows the X‐chromosome to be exceptional in how it contributes to “rules” of speciation. Until recently, however, the nematode phylum has been nearly silent on this issue, despite the model organism Caenorhabditis elegans having touched most other topics in biology. Studies of speciation with Caenorhabditis accelerated with the recent discovery of species pairs showing partial...

Everyone appreciates the happy fiction that species conform to the simple theoretical convenience of a single panmictic population. In speciation genetics, a further standard simplification is that it is only those genetic differences that are fixed between diverging populations that need concern us in order to understand the accumulation of intrinsic barriers to reproduction. To a first approximation, of course, both of these...

The genomic density of sequence polymorphisms critically affects the sensitivity of inferences about ongoing sequence evolution, function and demographic history. Most animal and plant genomes have relatively low densities of polymorphisms, but some species are hyperdiverse with neutral nucleotide heterozygosity exceeding 5%. Eukaryotes with extremely large populations, mimicking bacterial and viral populations, present novel...

Molecular hyperdiversity has been documented in viruses, prokaryotes and eukaryotes. Such organisms undermine the assumptions of the infinite‐sites mutational model, because multiple mutational events at a site comprise a non‐negligible portion of polymorphisms. Moreover, different sampling schemes of individuals from species with subdivided populations can profoundly influence resulting patterns and interpretations of molecul...

Most relatives of the self‐fertilizing hermaphroditic nematode model organism Caenorhabditis elegans reproduce via obligate outbreeding between males and females, which also represents the ancestral mode of reproduction within the genus. However, little is known about the scope of genetic diversity and differentiation within such gonochoristic species, especially those found outside of temperate Europe and North America. It is...