Microenvironments can have considerable physiological consequences for the inhabitants by influencing the movements of individual members. The microenvironment can permit more diverse aggregation patterns or restrict movements to certain dimensions. Here, we tested whether aspects of the microenvironment that influenced aggregation patterns also influenced the energetics of groups of young animals. We tested the effects of enclosure configuration on the group temperature and respiration of infant mice (Mus musculus). We monitored the huddle temperature and...

Consumers typically prefer freedom of choice, but when faced with a choice they might regret, they may prefer freedom from choice. Eight experiments show that people delegate difficult decisions, regardless of the decision’s importance, and regardless of their potential surrogate’s expertise. Delegation stems from a desire to avoid responsibility for potentially making the wrong choice rather than simply the desire to avoid the possibility of a poor outcome: although anticipated disappointment with the outcome and...

Adaptive variation in social behavior depends upon standing genetic variation, but we know little about how evolutionary forces shape genetic diversity relevant to brain and behavior. In prairie voles (Microtus ochrogaster), variants at the Avpr1a locus predict expression of the vasopressin 1a receptor in the retrosplenial cortex (RSC), a brain region that mediates spatial and contextual memory; cortical V1aR abundance in turn predicts diversity in space-use and sexual fidelity in the field. To examine the...

Background: Heterochronic shifts during mid- to late stages of organismal development have been proposed as key mechanisms generating phenotypic diversity. To determine whether late heterochronic shifts underlie derived floral morphologies within Jaltomata (Solanaceae)—a genus whose species have extensive and recently evolved floral diversity—we compared floral development of four diverse species (including an ambiguously ancestral or secondarily derived rotate, two putatively independently evolved campanulate, and a tubular morph) to the ancestral rotate floral form, as well...

A critical challenge in the science and practice of restoration ecology is to understand the drivers of variation in restoration outcomes. Soil microbial communities may have a role in explaining this variation due to both site-to-site variation in the composition of soil microbial communities and due to variation that can arise due to plant-soil feedbacks. We tested the relative importance of between-site variation in soil microbial community composition and plant-soil feedbacks in shaping plant community...

Niche construction occurs when organisms modify their environments and alter selective conditions through their physiology and behaviours. Such modifications can bias phenotypic variation and enhance organism–environment fit. Yet few studies exist that experimentally assess the degree to which environmental modifications shape developmental and fitness outcomes, how their influences may differ among species and identify the underlying proximate mechanisms. Here, we experimentally eliminate environmental modifications from the developmental environment of Onthophagus dung beetles. We show that...

Animals living in temperate climates are faced with the challenge of reproducing only when environmental conditions are suitable for offspring survival. Environmental cues signalling current and future energy availability (e.g., food availability and photoperiod respectively) are used to appropriately time reproduction. The precise neuroendocrine mechanisms regulating reproduction in response to these cues are unknown. The goal of the present study was to investigate a functional role for kisspeptin, a neuropeptide that shows promise as a...

Epistatic interactions can greatly impact evolutionary phenomena, particularly the process of adaptation. Here, we leverage four parallel experimentally evolved lineages to study the emergence and trajectories of epistatic interactions in the social bacterium Myxococcus xanthus. A social gene (pilA) necessary for effective group swarming on soft agar had been deleted from the common ancestor of these lineages. During selection for competitiveness at the leading edge of growing colonies, two lineages evolved qualitatively novel mechanisms for...

A central tenet of speciation research is the need to identify reproductive isolating barriers. One approach to this line of research is to identify the phenotypes that lead to reproductive isolation. Several studies on flowering plants have shown that differences in style length contribute to reproductive isolation between species, leading us to consider whether style length could act as a reproductive barrier among populations of a single species. This could occur if style length varied...

Reproductive isolation can rise either as a consequence of genomic divergence in allopatry or as a byproduct of divergent selection in parapatry. To determine whether reproductive isolation in gynodioecious Silene nutans results from allopatric divergence or from ecological adaptation following secondary contact, we investigated the pattern of postzygotic reproductive isolation and hybridization in natural populations using two phylogeographic lineages, western (W1) and eastern (E1). Experimental crosses between the lineages identified strong, asymmetric postzygotic isolation between...

Increasing access to extensively replicated and broadly distributed tree-ring collections has led to a greater use of these large data sets to investigate climate forcing on tree growth. However, the number of chronologies added to large accessible databases is declining and few are updated, while chronologies are often sparsely distributed and are more representative of marginal growing environments. On the other hand, National Forest Inventories (NFI), although poorly replicated at the plot level as compared...

Most research on dynamics and impacts of plant invasions has evaluated patterns and effects over brief time periods (i.e. <4 years). As such, little is known about the persistence of invasions and their long-term impacts on native species. To experimentally evaluate longer-term effects of invasions, we established field plots with native tree and herbaceous species and then invaded half of the plots with the most widespread invasive grass in the eastern United States (Microstegium vimineum)....

Reports of female song, once considered a rarity, have recently increased across a variety of avian taxa. Females of many species can be induced to produce male-like song with exogenous testosterone, but observations of female song in free-living birds remain limited by incomplete sampling of females. Here, we report three independent observations of female dark-eyed juncos (Junco hyemalis) producing male-like song early in the breeding season (i.e. post-territory establishment, pre-nesting) in a recently established non-migratory,...

p62 is a scaffolding adaptor implicated in the clearance of protein aggregates by autophagy. Reactive oxygen species (ROS) can either stimulate or inhibit NFκB-mediated gene expression influencing cellular fate. We studied the effect of hydrogen peroxide (H2O2)-mediated oxidative stress and NFκB signaling on p62 expression in the retinal pigment epithelium (RPE) and investigated its role in regulation of autophagy and RPE survival against oxidative damage. Cultured human RPE cell line ARPE-19 and primary human adult...

Species radiations may be facilitated by phenotypic differentiation already present within populations, such as those arising through sex-specific development or developmental processes biased toward particular reproductive or trophic morphs. We sought to test this hypothesis by utilizing a comparative transcriptomic approach to contrast among and within-species differentiation using three horned beetle species in the genus Onthophagus. These three species exhibit differences along three phenotypic axes reflective of much of the interspecific diversity present within the...

Genome-scale sequencing has been of great benefit in recovering species trees, but has not provided final answers. Despite the rapid accumulation of molecular sequences, resolving short and deep branches of the tree of life has remained a challenge, and has prompted the development of new strategies that can make the best use of available data. One such strategy – the concatenation of gene alignments – can be successful when coupled with many tree estimation methods,...

Over the past 25 years, the plant-soil feedback (PSF) framework has catalyzed our understanding of how belowground microbiota impact plant fitness and species coexistence. Here, we apply a novel extension of this framework to microbiota associated with aboveground tissues, termed ‘plant-phyllosphere feedback (PPFs)’. In parallel greenhouse experiments, rhizosphere and phyllosphere microbiota of con- and heterospecific hosts from four species were independently manipulated. In a third experiment, we tested the combined effects of soil and phyllosphere...

Virulent parasites can depress the densities of their hosts. Taxa that reduce disease via dilution effects might alleviate this burden. However, ‘diluter’ taxa can also depress host densities through competition for shared resources. The combination of disease and interspecific competition could even drive hosts extinct. Then again, genetically variable host populations can evolve in response to both competitors and parasites. Can rapid evolution rescue host density from the harm caused by these ecological enemies? How...

Natural ecosystems are shaped along two fundamental axes, space and time, but how biodiversity is partitioned along both axes is not well understood. Here, we show that the relationship between temporal and spatial biodiversity patterns can vary predictably according to habitat characteristics. By quantifying seasonal and annual changes in larval dragonfly communities across a natural predation gradient we demonstrate that variation in the identity of top predator species is associated with systematic differences in spatio-temporal...

Divergence in phenotypic traits often contributes to premating isolation between lineages, but could also promote isolation at postmating stages. Phenotypic differences could directly result in mechanical isolation or hybrids with maladapted traits; alternatively, when alleles controlling these trait differences pleiotropically affect other components of development, differentiation could indirectly produce genetic incompatibilities in hybrids. Here, we determined the strength of 9 postmating and intrinsic postzygotic reproductive barriers among 10 species of Jaltomata (Solanaceae), including species with...

The analysis of large datasets describing reproductive isolation between species has been extremely influential in the study of speciation. However, the statistical methods currently used for these data limit the ability to make direct inferences about the factors predicting the evolution of reproductive isolation. As a result, our understanding of iconic patterns and rules of speciation rely on indirect analyses that have clear statistical limitations. Phylogenetic mixed models are commonly used in ecology and evolution,...

Climate change has the potential to affect the ecology and evolution of every species on Earth. Although the ecological consequences of climate change are increasingly well documented, the effects of climate on the key evolutionary process driving adaptation—natural selection—are largely unknown. We report that aspects of precipitation and potential evapotranspiration, along with the North Atlantic Oscillation, predicted variation in selection across plant and animal populations throughout many terrestrial biomes, whereas temperature explained little variation. By...

Gene flow can impede the evolution of reproductive isolating barriers between species. Reinforcement is the process by which pre-zygotic reproductive isolation evolves in sympatry due to selection to decrease costly hybridization. It is known that reinforcement can be prevented by too much gene flow, but we still do not know how often have pre-zygotic barriers evolved in the presence of gene flow or how much gene flow can occur during reinforcement. Flower color divergence in...

If acquired associations are to accurately represent real relevance relations, there is motivation for the hypothesis that learning will, in some circumstances, be more appropriately modelled, not as direct dependence, but as conditional independence. In a serial compound conditioning experiment, two groups of rats were presented with a conditioned stimulus (CS1) that imperfectly (50%) predicted food, and was itself imperfectly predicted by a CS2. Groups differed in the proportion of CS2 presentations that were ultimately...