Pollinator and host sharing lead to hybridization and introgression in Panamanian free-standing figs, but not in their pollinator wasps.

Obligate pollination mutualisms, in which plant and pollinator lineages depend on each other for reproduction, often exhibit high levels of species specificity. However, cases in which two or more pollinator species share a single host species (host sharing), or two or more host species share a single pollinator species (pollinator sharing), are known to occur in current ecological time. Further, evidence for host switching in evolutionary time is increasingly being recognized in these systems.

Genome-wide sequence data show no evidence of hybridization and introgression among pollinator wasps associated with a community of Panamanian strangler figs.

The specificity of pollinator host choice influences opportunities for reproductive isolation in their host plants. Similarly, host plants can influence opportunities for reproductive isolation in their pollinators. For example, in the fig and fig wasp mutualism, offspring of fig pollinator wasps mate inside the inflorescence that the mothers pollinate.

A phylogenomic perspective on the evolutionary history of the stonefly genus Suwallia (Plecoptera: Chloroperlidae) revealed by ultraconserved genomic elements.

Evolutionary biologists have long sought to disentangle phylogenetic relationships among taxa spanning the tree of life, an increasingly important task as anthropogenic influences accelerate population declines and species extinctions, particularly in insects. Phylogenetic analyses are commonly used to identify unique evolutionary lineages, to clarify taxonomic designations of the focal taxa, and to inform conservation decisions. Advances in DNA sequencing techniques have increasingly facilitated the ability of researchers to apply genomic methods to phylogenetic analyses, even for non-model organisms.

Inferring processes of coevolutionary diversification in a community of Panamanian strangler figs and associated pollinating wasps.

The fig and pollinator wasp obligate mutualism is diverse (∼750 described species), ecologically important, and ancient (∼80 Ma). Once thought to be an example of strict one-to-one cospeciation, current thinking suggests genera of pollinator wasps codiversify with corresponding sections of figs, but the degree to which cospeciation or other processes contribute to the association at finer scales is unclear. Here, we use genome-wide sequence data from a community of Panamanian strangler figs and associated wasp pollinators to estimate the relative contributions of four evolutionary processes generating cophylogenetic patterns in this mutualism: cospeciation, host switching, pollinator speciation, and pollinator extinction.

Do ecological communities disperse across biogeographic barriers as a unit?

Biogeographic barriers have long been implicated as drivers of biological diversification, but how these barriers influence co-occurring taxa can vary depending on factors intrinsic to the organism and in their relationships with other species. Due to the interdependence among taxa, ecological communities present a compelling opportunity to explore how interactions among species may lead to a shared response to historical events. Here we collect single nucleotide polymorphism data from five commensal arthropods associated with the Sarracenia alata carnivorous pitcher plant, and test for codiversification across the Mississippi River, a major biogeographic barrier in the southeastern United States.

Phylogeographic concordance factors quantify phylogeographic congruence among co-distributed species in the Sarracenia alata pitcher plant system.

Comparative phylogeographic investigations have identified congruent phylogeographic breaks in co-distributed species in nearly every region of the world. The qualitative assessments of phylogeographic patterns traditionally used to identify such breaks, however, are limited because they rely on identifying monophyletic groups across species and do not account for coalescent stochasticity. Only long-standing phylogeographic breaks are likely to be obvious; many species could have had a concerted response to more recent landscape events, yet possess subtle signs of phylogeographic congruence because ancestral polymorphism has not completely sorted.

Biogeographic barriers drive co-diversification within associated eukaryotes of the Sarracenia alata pitcher plant system.

Understanding if the members of an ecological community have co-diversified is a central concern of evolutionary biology, as co-diversification suggests prolonged association and possible coevolution. By sampling associated species from an ecosystem, researchers can better understand how abiotic and biotic factors influence diversification in a region. In particular, studies of co-distributed species that interact ecologically can allow us to disentangle the effect of how historical processes have helped shape community level structure and interactions.

The evolution of phylogeographic data sets.

Empirical phylogeographic studies have progressively sampled greater numbers of loci over time, in part motivated by theoretical papers showing that estimates of key demographic parameters improve as the number of loci increases. Recently, next-generation sequencing has been applied to questions about organismal history, with the promise of revolutionizing the field. However, no systematic assessment of how phylogeographic data sets have changed over time with respect to overall size and information content has been performed.

Poor fit to the multispecies coalescent is widely detectable in empirical data.

Model checking is a critical part of Bayesian data analysis, yet it remains largely unused in systematic studies. Phylogeny estimation has recently moved into an era of increasingly complex models that simultaneously account for multiple evolutionary processes, the statistical fit of these models to the data has rarely been tested. Here we develop a posterior predictive simulation-based model check for a commonly used multispecies coalescent model, implemented in *BEAST, and apply it to 25 published data sets.

How to fail at species delimitation.

Species delimitation is the act of identifying species-level biological diversity. In recent years, the field has witnessed a dramatic increase in the number of methods available for delimiting species. However, most recent investigations only utilize a handful (i.

Model selection as a tool for phylogeographic inference: an example from the willow Salix melanopsis.

Phylogeographic inference has typically relied on analyses of data from one or a few genes to provide estimates of demography and population histories. While much has been learned from these studies, all phylogeographic analysis is conditioned on the data, and thus, inferences derived from data that represent a small sample of the genome are unavoidably tenuous. Here, we demonstrate one approach for moving beyond classic phylogeographic research.

Multilocus species delimitation in a complex of morphologically conserved trapdoor spiders (mygalomorphae, antrodiaetidae, aliatypus).

Species are a fundamental unit for biological studies, yet no uniform guidelines exist for determining species limits in an objective manner. Given the large number of species concepts available, defining species can be both highly subjective and biased. Although morphology has been commonly used to determine species boundaries, the availability and prevalence of genetic data has allowed researchers to use such data to make inferences regarding species limits.

Inferring species trees from gene trees in a radiation of California trapdoor spiders (Araneae, Antrodiaetidae, Aliatypus).

Background: The California Floristic Province is a biodiversity hotspot, reflecting a complex geologic history, strong selective gradients, and a heterogeneous landscape. These factors have led to high endemic diversity across many lifeforms within this region, including the richest diversity of mygalomorph spiders (tarantulas, trapdoor spiders, and kin) in North America. The trapdoor spider genus Aliatypus encompasses twelve described species, eleven of which are endemic to California.

Disseminated hereditary gastrointestinal polyposis with orocutaneous hamartomatosis (Cowden's disease).

Cowden's disease, first described by Lloyd and Dennis in 1962, is a rare disseminated polyposis of the gastrointestinal tract with an autosomal dominant inheritance pattern, infrequently cited in the contemporary gastroenterological literature. In addition to multiple polyps, which are scattered throughout the gastrointestinal tract from the mouth to the anus, orocutaneous hamartomas and frequent benign and malignant cutaneous, thyroid and breast tumors are thought to represent the most common manifestations of the disease. Ectodermal lesions are most frequently reported as a salient feature, and represent the most consistent element in the definition of this condition in the majority of cases, most of which are recorded in the dermatological literature (multiple hamartoma syndrome or Cowden's disease).