Long-term effectiveness and generality of practical functional assessment and skill-based treatment.

There are several considerations to address when conducting functional communication training for challenging behavior in a school setting, such as the need for schedule thinning and maintenance across staff and the need to establish a variety of appropriate classroom skills. There are several strategies for conducting schedule thinning following functional communication training and for transferring effects across people or settings. However, there are few examples of these processes in natural settings with relevant caregivers and with long-term maintenance of effects.

The effect of experimental pollinator decline on pollinator-mediated selection on floral traits.

Human-mediated environmental change, by reducing mean fitness, is hypothesized to strengthen selection on traits that mediate interactions among species. For example, human-mediated declines in pollinator populations are hypothesized to reduce mean seed production by increasing the magnitude of pollen limitation and thus strengthen pollinator-mediated selection on floral traits that increase pollinator attraction or pollen transfer efficiency. To test this hypothesis, we measured two female fitness components and six floral traits of plants exposed to supplemental hand-pollination, ambient open-pollination, or reduced open-pollination treatments.

Evolvability and trait function predict phenotypic divergence of plant populations.

Understanding the causes and limits of population divergence in phenotypic traits is a fundamental aim of evolutionary biology, with the potential to yield predictions of adaptation to environmental change. Reciprocal transplant experiments and the evaluation of optimality models suggest that local adaptation is common but not universal, and some studies suggest that trait divergence is highly constrained by genetic variances and covariances of complex phenotypes. We analyze a large database of population divergence in plants and evaluate whether evolutionary divergence scales positively with standing genetic variation within populations (evolvability), as expected if genetic constraints are evolutionarily important.

Simulated pollinator decline has similar effects on seed production of female and hermaphrodite Lobelia siphilitica, but different effects on selection on floral traits.

Premise: Pollinator decline, by reducing seed production, is predicted to strengthen natural selection on floral traits. However, the effect of pollinator decline on gender dimorphic species (such as gynodioecious species, where plants produce female or hermaphrodite flowers) may differ between the sex morphs: if pollinator decline reduces the seed production of females more than hermaphrodites, then it should also have a larger effect on selection on floral traits in females than in hermaphrodites.

Methods: To simulate pollinator decline, we experimentally reduced pollinator access to female and hermaphrodite Lobelia siphilitica plants.

Do Genetic Drift and Gene Flow Affect the Geographic Distribution of Female Plants in Gynodioecious ?

Variation in population sex ratio is particularly pronounced in gynodioecious angiosperms. Extremely high female frequencies in gynodioecious populations cannot be readily explained by selective forces alone. To assess the contributions of drift and gene flow to extreme sex-ratio variation, we documented sex ratio and population size in 92 populations of Lobelia siphilitica across its range and genotyped plants using plastid and nuclear genetic markers.

Plasticity in floral longevity and sex-phase duration of Lobelia siphilitica in response to simulated pollinator declines.

Premise: Pollinator declines can reduce the quantity and quality of pollination services, resulting in less pollen deposited on flowers and lower seed production by plants. In response to these reductions, plant species that cannot autonomously self-pollinate and thus are dependent on pollinators to set seed could plastically adjust their floral traits. Such plasticity could increase the opportunity for outcross pollination directly, as well as indirectly by affecting inflorescence traits.

Defence by duplication: The relation between phenotypic glyphosate resistance and EPSPS gene copy number variation in Amaranthus palmeri.

Gene copy number variation (CNV) has been increasingly associated with organismal responses to environmental stress, but we know little about the quantitative relation between CNV and phenotypic variation. In this study we quantify the relation between variation in EPSPS (5-enolpyruvylshikimate-3-phosphate synthase) copy number using digital drop PCR and variation in phenotypic glyphosate resistance in 22 populations of Amaranthus palmeri (Palmer Amaranth), a range-expanding agricultural weed. Overall, we detected a significant positive relation between population mean copy number and resistance.

A sit-and-wait predator, but not an active-pursuit predator, alters pollinator-mediated selection on floral traits.

Indirect species interactions are ubiquitous in nature, often outnumbering direct species interactions. Yet despite evidence that indirect interactions have strong ecological effects, relatively little is known about whether they can shape adaptive evolution by altering the strength and/or direction of natural selection. We tested whether indirect interactions affect the strength and direction of pollinator-mediated selection on floral traits of the bumble-bee pollinated wildflower Lobelia siphilitica.

Global gene flow releases invasive plants from environmental constraints on genetic diversity.

When plants establish outside their native range, their ability to adapt to the new environment is influenced by both demography and dispersal. However, the relative importance of these two factors is poorly understood. To quantify the influence of demography and dispersal on patterns of genetic diversity underlying adaptation, we used data from a globally distributed demographic research network comprising 35 native and 18 nonnative populations of Species-specific simulation experiments showed that dispersal would dilute demographic influences on genetic diversity at local scales.

Simulated pollinator declines intensify selection on floral traits that facilitate selfing and outcrossing in Impatiens capensis.

Premise: Anthropogenic environmental change is causing pollinator populations to decline. These declines should intensify selection for floral traits that facilitate outcrossing by making plants more attractive to pollinators and/or for floral traits that facilitate selfing in the absence of pollinators. However, the effect of pollinator declines on selection on floral traits could be modified by other environmental factors such as herbivores.

Beyond balancing selection: frequent mitochondrial recombination contributes to high-female frequencies in gynodioecious Lobelia siphilitica (Campanulaceae).

Gynodioecy is a sexual system in which females and hermaphrodites co-occur. In most gynodioecious angiosperms, sex is determined by an interaction between mitochondrial male-sterility genes (CMS) that arise via recombination and nuclear restorer alleles that evolve to suppress them. In theory, gynodioecy occurs when multiple CMS types are maintained at equilibrium frequencies by balancing selection.

Load Carriage and Physical Exertion Influence Cognitive Control in Military Scenarios.

Introduction: Physical exertion has both beneficial and detrimental effects on cognitive performance, particularly cognitive control. Research into physical exertion under conditions of load carriage is particularly important given that military personnel and first responders must perform optimally under such combinatorial physical stressors. The present work sought to characterize cognitive control as a function of physical exertion and load carriage in a military operational scenario.

A meta-analysis of the agents of selection on floral traits.

Floral traits are hypothesized to evolve primarily in response to selection by pollinators. However, selection can also be mediated by other environmental factors. To understand the relative importance of pollinator-mediated selection and its variation among trait and pollinator types, we analyzed directional selection gradients on floral traits from experiments that manipulated the environment to identify agents of selection.

Response to Comment on "Precipitation drives global variation in natural selection".

The comment by Myers-Smith and Myers focuses on three main points: (i) the lack of a mechanistic explanation for climate-selection relationships, (ii) the appropriateness of the climate data used in our analysis, and (iii) our focus on estimating climate-selection relationships across (rather than within) taxonomic groups. We address these critiques in our response.

What Are the Environmental Determinants of Phenotypic Selection? A Meta-analysis of Experimental Studies.

Although many selection estimates have been published, the environmental factors that cause selection to vary in space and time have rarely been identified. One way to identify these factors is by experimentally manipulating the environment and measuring selection in each treatment. We compiled and analyzed selection estimates from experimental studies.

Physiological effects of temperature do not explain prevalence of females in populations of gynodioecious growing in warmer climates.

Premise Of The Study: Gynodioecy is a sexual polymorphism whereby female and hermaphroditic plants co-occur within populations. In many gynodioecious species, stressful abiotic environments are associated with higher frequencies of females. This association suggests that abiotic stress affects the relative fitness of females and hermaphrodites and, thus, the maintenance of gynodioecy.

Precipitation drives global variation in natural selection.

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.

Why is gynodioecy a rare but widely distributed sexual system? Lessons from the Lamiaceae.

Gynodioecy, a sexual system where females and hermaphrodites co-occur, is found in << 1% of angiosperm species. To understand why gynodioecy is rare, we need to understand why females are maintained in some lineages, but not in others. We modelled the evolution of gynodioecy in the Lamiaceae, and investigated whether transition rates between gynodioecious and nongynodioecious states varied across the family.

Do Plants Eavesdrop on Floral Scent Signals?

Plants emit a diverse array of volatile organic compounds that can function as cues to other plants. Plants can use volatiles emitted by neighbors to gain information about their environment, and respond by adjusting their phenotype. Less is known about whether the many different volatile signals that plants emit are all equally likely to function as cues to other plants.

Frequency-dependent fitness in gynodioecious Lobelia siphilitica.

Selection is frequency dependent when an individual's fitness depends on the frequency of its phenotype. Frequency-dependent selection should be common in gynodioecious plants, where individuals are female or hermaphroditic; if the fitness of females is limited by the availability of pollen to fertilize their ovules, then they should have higher fitness when rare than when common. To test whether the fitness of females is frequency dependent, we manipulated the sex ratio in arrays of gynodioecious Lobelia siphilitica.

The catecholamine neurotransmitter precursor tyrosine increases anger during exposure to severe psychological stress.

Rationale: Acute stress produces behavioral and physiological changes modulated by central catecholamines (CA). Stress increases CA activity, and depletion of CA stores reduces responses to stress. Increasing CA activity by administration of the dietary amino acid CA precursor tyrosine may increase responsiveness to stress.

Testing models of sex ratio evolution in a gynodioecious plant: female frequency covaries with the cost of male fertility restoration.

In many gynodioecious species, cytoplasmic male sterility genes (CMS) and nuclear male fertility restorers (Rf) jointly determine whether a plant is female or hermaphrodite. Equilibrium models of cytonuclear gynodioecy, which describe the effect of natural selection within populations on the sex ratio, predict that the frequency of females in a population will primarily depend on the cost of male fertility restoration, a negative pleiotropic effect of Rf alleles on hermaphrodite fitness. Specifically, when the cost of restoration is higher, the frequency of females at equilibrium is predicted to be higher.

The evolutionary ecology of cytonuclear interactions in angiosperms.

Interactions between cytoplasmic and nuclear genomes have significant evolutionary consequences. In angiosperms, the most common cytonuclear interaction is between mitochondrial genes that disrupt pollen production (cytoplasmic male sterility, CMS) and nuclear genes that restore it (nuclear male fertility restorers, Rf). The outcome of CMS/Rf interactions can depend on whether Rf alleles have negative pleiotropic effects on fitness.

Lobelia siphilitica plants that escape herbivory in time also have reduced latex production.

Flowering phenology is an important determinant of a plant's reproductive success. Both assortative mating and niche construction can result in the evolution of correlations between phenology and other reproductive, functional, and life history traits. Correlations between phenology and herbivore defence traits are particularly likely because the timing of flowering can allow a plant to escape herbivory.