Scientific societies have the potential to catalyze support for communities that have been historically excluded from science. Many of these societies have formed committees to propose and administer initiatives to promote the career and well‐being of their members, with a special emphasis on racial and ethnic minorities. Yet, these societies are rarely armed with data to inform their proposals. Three

Recently diverged species often show incomplete reproductive isolation and subsequently experience hybridization and introgression. The plant genus Mimulus includes many such examples of closely related taxa that prove useful for studying incipient speciation. However, Sandstedt et al. (4) show that in contrast to other Mimulus species, species of the M. tilingii complex are characterized by strong

March 2021 marks the 75th anniversary of the Society for the Study of Evolution (SSE), a society that remains vibrant, with an expanding international membership. Much has changed since 1946, both in terms of how the SSE operates (see Smocovitis 1994 for the early history of the SSE) and in terms of the foci of research undertaken by its members and published in its journals. In recognition of the

Natural populations are often exposed to temporally varying environments. Evolutionary dynamics in varying environments have been extensively studied, although understanding the effects of varying selection pressures remains challenging. Here, we investigate how cycling between a pair of statistically related fitness landscapes affects the evolved fitness of an asexually reproducing population. We

One of the primary goals of macroevolutionary biology has been to explain general trends in long‐term diversity patterns, including whether such patterns correspond to an upscaling of processes occurring at lower scales. Reconstructed phylogenies often show decelerated lineage accumulation over time. This pattern has often been interpreted as the result of diversity‐dependent (DD) diversification,

The distribution and abundance of polyploids has intrigued biologists since their discovery in the early 20th century. A pattern in nature that may give insight to processes that shape the distribution and abundance of polyploids is that polyploid populations are sometimes associated with peripheral habitats within the range of a species of mixed ploidy. Here, adaptation and competition of a diploid

The kinetic skull is a key innovation that allowed snakes to capture, manipulate, and swallow prey exclusively using their heads using the coordinated movement of eight bones. Despite these unique feeding behaviors, patterns of evolutionary integration and modularity within the feeding bones of snakes in a phylogenetic framework have yet to be addressed. Here, we use a dataset of 60 μCT‐scanned skulls

Adaptation through natural selection may be the only means by which small and fragmented plant populations will persist through present day environmental change. A population's additive genetic variance for fitness (VA(W)) represents its immediate capacity to adapt to the environment in which it exists. We evaluated this property for a population of the annual legume Chamaecrista fasciculata through

Hybrid phenotypes that contribute to postzygotic reproductive isolation often exhibit pronounced asymmetry, both between reciprocal crosses and between the sexes in accordance with Haldane's rule. Inviability in mammalian hybrids is associated with parent‐of‐origin placental growth abnormalities for which misregulation of imprinted gene (IGs) is the leading candidate mechanism. However, direct evidence

Standard metabolic rate (SMR), defined as the minimal energy expenditure required for self‐maintenance, is a key physiological trait. Few studies have estimated its relationship with fitness, most notably in insects. This is presumably due to the difficulty of measuring SMR in a large number of very small individuals. Using high‐throughput flow‐through respirometry and a Drosophila melanogaster laboratory

Larger species tend to feed on abundant resources, which nonetheless have lower quality or degradability, the so‐called Jarman‐Bell principle. The “eat more” hypothesis posits that larger animals compensate for lower quality diets through higher consumption rates. If so, evolutionary shifts in metabolic scaling should affect the scope for this compensation, but whether this has happened is unknown

The evolution of mate choice is a major topic in evolutionary biology because it is thought to be a key factor in trait and species diversification. Here, we aim at uncovering the ecological conditions and genetic architecture enabling the puzzling evolution of disassortative mating based on adaptive traits. This rare form of mate choice is observed for some polymorphic traits but theoretical predictions

Most subterranean animals are assumed to have evolved from surface ancestors following colonization of a cave system; however, very few studies have raised the possibility of “subterranean speciation” in underground habitats (i.e., obligate cave‐dwelling organisms [troglobionts] descended from troglobiotic ancestors). Numerous endemic subterranean diving beetle species from spatially discrete calcrete

Hybridization between divergent lineages generates new allelic combinations. One mechanism that can hinder the formation of hybrid populations is mitonuclear incompatibility, that is, dysfunctional interactions between proteins encoded in the nuclear and mitochondrial genomes (mitogenomes) of diverged lineages. Theoretically, selective pressure due to mitonuclear incompatibility can affect genotypes

How do male mating behaviors evolve in response to a competitive social environment? Using an experimental evolution approach, Dore et al. demonstrated that sociosexual environments can lead to the evolution of novel plastic male mating behaviors in Drosophila melanogaster, with both mating latency and mating duration extended in male‐biased populations after exposure to male rivals.

How do gene variants with opposing effects on fitness in juvenile and adult insects perform in different ecological settings? Marden et al. used alleles of two antagonistic genes involved in metabolism and oxygen sensing in the Glanville fritillary butterfly as a model to demonstrate how these genes can antagonistically affect larval development and the adaptation of adults to different landscapes

Antagonistic coevolution has long been suggested to help maintain host genetic variation. While, ecological and epidemiological feedbacks are known to have important consequences on coevolutionary allele frequency dynamics, their effects on the maintenance of genetic variation remains poorly understood. Here, we extend previous work on the maintenance of genetic variation in a classic matching‐alleles

Understanding how organisms adapt to new environments is a key problem in evolution, yet it remains unclear whether phenotypic plasticity generally facilitates or hinders this process. Here we studied evolved and plastic responses to water‐stress in lab‐born descendants of wild house mice (Mus musculus domesticus) collected from desert and non‐desert environments and measured gene expression and organismal

Rapid divergence in genital structures among nascent species has been posited to be an early‐evolving cause of reproductive isolation, although evidence supporting this idea as a widespread phenomenon remains mixed. Using a collection of interspecific introgression lines between two Drosophila species that diverged approximately 240,000 years ago, we tested the hypothesis that even modest divergence

Long bones comprise articular ends (epiphyses) joined by transitional metaphyses and a diaphysis (shaft). The structure of the latter is often viewed as regularly tubular across tetrapods (limbed vertebrates). However, assessments of the bone structure along the whole diaphysis are rare. Here, I assess whole‐diaphysis profiles of global compactness (bone fraction) of 164 species of extant and extinct

Evolutionary biologists frequently wish to measure the fitness of alternative phenotypes using behavioral experiments. However, many phenotypes are complex. One example is coloration: camouflage aims to make detection harder, while conspicuous signals (e.g., for warning or mate attraction) require the opposite. Identifying the hardest and easiest to find patterns is essential for understanding the

In socially monogamous species, male reproductive success consists of “within‐pair” offspring produced with their socially paired mate(s), and “extra‐pair” offspring produced with additional females throughout the population. Both reproductive pathways offer distinct opportunities for selection in wild populations, as each is composed of separate components of mate attraction, female fecundity, and

Can sexual conflict over the length of male versus female maturity phases within hermaphroditic flowers promote the evolution of gynodioecy? Wang et al. found that hermaphroditic plants of Cyananthus delavayi exhibited a plastic response to a failure in pollen removal, which compromised seed production by reducing the duration of the female maturity phase to the benefit of the male phase. Sexual conflict

While giraffes maintain the usual mammalian cervical number of seven vertebrae, their first thoracic vertebra (T1) exhibits aberrant anatomy and has been hypothesized to functionally elongate the neck. We test this ‘functional elongation hypothesis’ by combining phylogenetically informed analyses of neck length, three‐dimensional (3D) vertebral shape, and of the functional significance of shape differences

Mate choice for genetic benefits remains controversial, largely because few studies have estimated the relative contributions of additive and non‐additive sources of genetic variation to offspring fitness. Moreover, there remains a deficit of these estimates for species where female‐mate preferences have been quantified in the wild, especially species characterized by monandry or monogamy. Here, we

Sexual selection is thought to be responsible for the rapid divergent evolution of male genitalia with several studies detecting multivariate sexual selection on genital form. However, in most cases, selection is only estimated during a single episode of selection, which provides an incomplete view of net selection on genital traits. Here, we estimate the strength and form of multivariate selection

Adaptive radiations are often stereotypical, as populations repeatedly specialize along conserved environmental axes. Phenotypic plasticity may be similarly stereotypical, as individuals respond to environmental cues. These parallel patterns of variation, which are often consistent across traits, have led to the proposition that plasticity can facilitate evolution along environmental gradients. This

Dietary restriction (DR), limiting calories or specific nutrients without malnutrition, extends lifespan across diverse taxa. Traditionally, this lifespan extension has been explained as a result of diet‐mediated changes in the trade‐off between lifespan and reproduction, with survival favored when resources are scarce. However, a recently proposed alternative suggests that the selective benefit of

Co‐distributed species may exhibit similar phylogeographic patterns due to shared environmental factors or discordant patterns attributed to the influence of species‐specific traits. Although either concordant or discordant patterns could occur due to chance, stark differences in key traits (e.g., dispersal ability) may readily explain differences between species. Multiple species’ attributes may affect

Diverse animal species engage in long‐distance migrations. Many migrants travel in groups, and communication within these groups may be important to survival and successful migration. We examined migration and communication in 36 species of wood warblers (Parulidae), songbirds which breed in North America and migrate in mixed‐species flocks to their wintering grounds. During migration, wood warblers

Although most invasive species engage in mutualism, we know little about how mutualism evolves as partners colonize novel environments. Selection on cooperation and standing genetic variation for mutualism traits may differ between a mutualism's invaded and native ranges, which could alter cooperation and coevolutionary dynamics. To test for such differences, we compare mutualism traits between invaded‐

Understanding the role of horizontal gene transfer (HGT) in adaptation is a key challenge in evolutionary biology. In microbes, an important mechanism of HGT is prophage acquisition (phage genomes integrated into bacterial chromosomes). Prophages can influence bacterial fitness via the transfer of beneficial genes (including antibiotic‐resistance genes, ARGs), protection from superinfecting phages

Phenotypic plasticity can either hinder or promote adaptation to novel environments. Recent studies that have quantified alignments between plasticity, genetic variation, and divergence propose that such alignments may reflect constraints that bias future evolutionary trajectories. Here, we emphasize that such alignments may themselves be a result of natural selection and do not necessarily indicate

Understanding how mutualisms persist over time requires investigations of how mutualist species coevolve and adapt to the interaction. In particular, the key factors in the evolution of mutualisms are the costs and benefits mutualists experience during the interaction. Here, we used a yeast nutritional mutualism to test how mutualists coevolve and adapt in an obligate mutualism. We allowed two yeast

Inferring the history of divergence between species in a framework that permits the presence of gene flow has been crucial for characterizing the “gray zone” of speciation, which is the period of time where lineages have diverged but have not yet achieved strict reproductive isolation. However, estimates of both divergence times and rates of gene flow often ignore spatial information, for example when

The relationship between organismal function and form is a cornerstone of biology because functional diversity is key to generating and maintaining ecological diversity. Morphological changes often occur in unison with behavioral or ecological transitions, and this process may foster diversification, but alternately could trap a species on an adaptive peak. We estimated the most comprehensive phylogenetic

Little is empirically known about the contribution of mutations to fitness in natural environments. However, Fisher's Geometric Model (FGM) provides a conceptual foundation to consider the influence of the environment on mutational effects. To quantify mutational properties in the field, we established eight sets of MA lines (7‐10 generations) derived from eight founders collected from natural populations

The diversity of body shapes is one of the most prominent features of phenotypic variation in vertebrates. Biologists, however, still lack a full understanding of the underlying morphological components that contribute to its diversity, particularly in endothermic vertebrates such as mammals. In this study, hypotheses pertaining to the evolution of the cranial and axial components that contribute to

Immigrant inviability can contribute to reproductive isolation (RI) during ecological speciation by reducing the survival of immigrants in non‐native environments. However, studies that assess the fitness consequence of immigrants moving from native to non‐native environments typically fail to explore the potential role of concomitant reductions in immigrant fecundity despite recent evidence suggesting

Does a male courting behavior proximately cause polyandry in a fruit fly species? Minekawa et al. found that in Drosophila prolongata, male flies vibrate their legs to overcome female remating suppression, resulting in multiple matings for females that otherwise may have remained monandrous.

Despite considerable progress in recent decades in dissecting the genetic causes of natural morphological variation, there is limited understanding of how variation within species ultimately contributes to species differences. We have studied patterning of the non‐sensory hairs, commonly known as “trichomes,” on the dorsal cuticle of first‐instar larvae of Drosophila. Most Drosophila species produce

Post‐copulatory sexual selection (PSS) is an important selective force that determines fitness in polyandrous species. PSS can be intense in some cases and can drive the evolution of remarkable ejaculate properties. In males, investment in ejaculate plays an important role in the outcome of PSS. Thus, males are expected to adaptively tailor their ejaculate according to the perceived competition in

Understanding the mechanisms underlying species divergence remains a central goal in evolutionary biology. Landscape genetics can be a powerful tool for examining evolutionary processes. We used genome‐wide scans to genotype samples from populations of eight Angophora species. Angophora is a small genus within the eucalypts comprising common and rare species in a heterogeneous landscape, making it

Exaggerated traits of pollinators have fascinated biologists for centuries. To understand their evolution, and their role in coevolutionary relationships, an essential first step is to understand how traits scale allometrically with body size, which may reveal underlying developmental constraints. Few pollination studies have examined how traits can adaptively diverge despite allometric constraints

Developmental plasticity describes the capacity of individuals with the same genotype to induce permanent change in a phenotype depending on a specific external input. One well‐studied example of adaptive developmental plasticity is the induction of facultative diapause in insects. Studies investigating the inheritance of diapause induction have suggested diverse genetic origins. However, only few

Convergent evolution is a major topic in evolutionary biology. Low bone cortical compactness (CC, a measure of porosity of cortical bone) in the extant genera of “tree sloths,” has been linked to their convergent slow arboreal ecology. This proposed relationship of low CC with a slow arboreal lifestyle suggests potential convergent evolution of this trait in other slow arboreal mammals. Femoral and

Spatiotemporal variation in natural selection is expected, but difficult to estimate. Pollinator‐mediated selection on floral traits provides a good system for understanding and linking variation in selection to differences in ecological context. We studied pollinator‐mediated selection in five populations of Dalechampia scandens (Euphorbiaceae) in Costa Rica and Mexico. Using a nonlinear path‐analytical

What conditions favor the evolution of large animal weapons? In the Japanese rhinoceros beetle, Trypoxylus dichotomus, del Sol et al. found that selection favors large horns in populations where males compete over guardianship of scarce female feeding territories. However, in other populations, an abundance of female feeding territories reduces the chance of mating success for these guarding males

Are the distributions of mountain species shifting up or downslope under climate change? Contrary to the long‐held view of global warming forcing an upslope shift of montane ecosystems, Salces‐Castellano et al. found that populations of a beetle tightly associated to cloud forests were isolated through the ice ages but in contact during interglacial periods, suggesting downslope shifts of cloud forest

The final formation of the Central American Isthmus (CAI) about 3.5 million years ago altered global ocean circulation, connected North and South America terrestrial biotas, and established the Caribbean Sea. The nature of this event creates a natural scenario to test vicariance, divergence, and speciation by allopatry. Studies have shown the effect of the CAI on marine and terrestrial species, but

Evolution. 2018 Oct;72(10):2267. https://doi.org/10.1111/evo.13605. Two years ago, I published an “Editorial Comment” about an exchange of Technical Comments in our journal. For context, a Technical Comment is a paper that offers new analyses, criticisms, or alternative interpretations of findings in research papers recently published in Evolution. The first critical Technical Comment goes out for

Following widespread infections of the most recent coronavirus known to infect humans, SARS‐CoV‐2, attention has turned to potential therapeutic options. With no drug or vaccine yet approved, one focal point of research is to evaluate the potential value of repurposing existing antiviral treatments, with the logical strategy being to identify at least a short‐term intervention to prevent within‐patient

When divergent populations form hybrids, hybrid fitness can vary with genome composition, current environmental conditions, and the divergence history of the populations. We develop analytical predictions for hybrid fitness, which incorporate all three factors. The predictions are based on Fisher's geometric model, and apply to a wide range of population genetic parameter regimes and divergence conditions

Animals often use assessment signals to communicate information about their quality to a variety of receivers, including potential mates, competitors, and predators. But what maintains reliable signaling and prevents signalers from signaling a better quality than they actually have? Previous work has shown that reliable signaling can be maintained if signalers pay fitness costs for signaling at different

High species richness and endemism in tropical mountains are recognized as major contributors to the latitudinal diversity gradient. The processes underlying mountain speciation, however, are largely untested. The prevalence of steep ecogeographic gradients and the geographic isolation of populations by topographic features are predicted to promote speciation in mountains. We evaluate these processes

The skeleton is a complex arrangement of anatomical structures that covary to various degrees depending on both intrinsic and extrinsic factors. Among the Feliformia, many species are characterized by predator lifestyles providing a unique opportunity to investigate the impact of highly specialized hypercarnivorous diet on phenotypic integration and shape diversity. To do so, we compared the shape

The additive genetic variation (VA) of fitness in a population is of particular importance to quantify its adaptive potential and predict its response to rapid environmental change. Recent statistical advances in quantitative genetics and the use of new molecular tools have fostered great interest in estimating fitness VA in wild populations. However, the value of VA for fitness in predicting evolutionary

How can we test whether biogeographic dispersal rates coincide with geologic events? Hua and Bromham developed a model‐based approach to generate a null distribution of colonization times under constant dispersal rates, overcoming a problem related to the geometry of phylogenetic trees.

The cognitive buffer hypothesis poses that brain size evolves to buffer individuals from environmental changes, increasing survival. Jiménez‐Ortega et al. (2020) explored this hypothesis using a phylogenetic path analysis and showed that there is a direct causal link between brain size and longevity in birds, even when allometric effects are taken into account. Furthermore, a synergistic model was

Little is known about the presence of incomplete convergence in the evolution of vertebrate taxa, as it is difficult to differentiate between evolutionary methods responsible for the appearance of similar forms. Grossnickle et al. present the first study of convergence evaluating all six extant glider clades using phylogenetic comparative methods. The authors find that the unique skeletal morphology