Background: Early childhood interventions have potential to offset the negative impact of early adversity. We evaluated the impact of a community-based parenting group intervention on child development in Zambia. Methods and Findings: We conducted a non-masked cluster-randomized controlled trial in Southern Province, Zambia. Thirty clusters of villages were matched based on population density and distance from the nearest health center, and randomly assigned to intervention (15 clusters, 268 caregiver-child dyads) or control (15 clusters, 258...

For animals that harbor photosynthetic symbionts within their tissues, such as corals, the different relative contributions of autotrophy versus heterotrophy to organismal energetic requirements have direct impacts on fitness. This is especially true for facultatively symbiotic corals, where the balance between host-caught and symbiont-produced energy can be altered substantially to meet the variable demands of a shifting environment. In this study, we utilized a temperate coral-algal system (the northern star coral, Astrangia poculata, and its...

The African brood parasitic finches (Vidua spp.) are host specialists that mimic the songs and nestling mouth markings of their finch hosts (family Estrildidae). Although recent molecular analyses suggest rapid speciation associated with host switches in some members of this group, the association of different Vidua lineages with particular host genera suggests the possibility of cospeciation at higher levels in the host and parasite phylogenies. We compared a phylogeny of all Vidua species with a...

Many organisms have evolved phenotypic plasticity but examples of a heritable genetic basis or genetic constraints for plasticity across environments remain scarce. Tadpoles of the Neotropical treefrog Dendropsophus ebraccatus alter tail coloration and shape differently in response to fish or aquatic insect predators. To assess the genetic basis of plasticity we raised 1020 tadpoles from 17 maternal half-sib pairs (34 unique families) individually with chemical cues of fish or aquatic insects, or with cue-free control...

Antibiotic resistance is often the result of mutations that block drug activity; however, bacteria also evade antibiotics by transiently expressing genes such as multidrug efflux pumps. A crucial question is whether transient resistance can promote permanent genetic changes. Previous studies have established that antibiotic treatment can select tolerant cells that then mutate to achieve permanent resistance. Whether these mutations result from antibiotic stress or preexist within the population is unclear. To address this question, we...

Batesian mimicry is characterized by phenotypic convergence between an unpalatable model and a palatable mimic. However, because convergent evolution may arise via alternative evolutionary mechanisms, putative examples of Batesian mimicry must be rigorously tested. Here we used artificial butterfly facsimiles (N=4000) to test the prediction that 1) palatable Limenitis lorquini butterflies should experience reduced predation when in sympatry with their putative model, Adelpha californica, 2) protection from predation on L. lorquini should erode outside of...

1. Context. Precipitation regimes are changing in response to climate change, yet understanding of how forest ecosystems respond to extreme droughts and pluvials remains incomplete. As future precipitation extremes will likely fall outside the range of historical variability, precipitation manipulation experiments (PMEs) are critical to advancing knowledge about potential ecosystem responses. However, few PMEs have been conducted in forests compared to short-statured ecosystems, and forest PMEs have unique design requirements and constraints. Moreover, past forest...

Vegetative dormancy, that is the temporary absence of aboveground growth for ≥ 1 year, is paradoxical, because plants cannot photosynthesise or flower during dormant periods. We test ecological and evolutionary hypotheses for its widespread persistence. We show that dormancy has evolved numerous times. Most species displaying dormancy exhibit life‐history costs of sprouting, and of dormancy. Short‐lived and mycoheterotrophic species have higher proportions of dormant plants than long‐lived species and species with other nutritional modes. Foliage...

Human societies depend on an Earth System that operates within a constrained range of nutrient availability, yet the recent trajectory of terrestrial nitrogen (N) availability is uncertain. Examining patterns of foliar N concentrations ([N]) and isotope ratios (15N) from more than 42,000 samples acquired over 37 years, here we show that foliar [N] declined by 8% and foliar 15N declined by 0.8 – 1.9 ‰. Examining patterns across different climate spaces, foliar 15N declined across...

Despite the known links between climate and biogeochemical cycling of N in tropical forests, fundamental knowledge of N cycling is still far from complete. Our objective was to ascertain differences in the N cycle of two tropical dry forests under contrasting precipitation regime (1240 or 642 mm of mean annual rainfall). To do so, we examined a short-term metric of N cycling (N concentration) and a more integrated metric of N cycling (natural abundance 15N)...

Understanding the causes of larval dispersal is a major goal of marine ecology, yet most research focuses on proximate causes. Here, we ask how ultimate, evolutionary causes affect dispersal. Building on Hamilton and May's 1977 classic paper (``Dispersal in stable habitats"), we develop analytic and simulation models for the evolution of dispersal kernels in spatially structured habitats. First, we investigate dispersal in a world without edges and find that most offspring disperse as far as...

Despite more than a century of biological research on the evolution and maintenance of mimetic signals, the relative frequencies of models and mimics necessary to establish and maintain Batesian mimicry in natural populations remains understudied. Here we investigate the frequency-dependent dynamics of imperfect Batesian mimicry, using predation experiments involving artificial butterfly models. We use two geographically distinct populations of Adelpha butterflies that vary in their relative frequencies of a putatively defended model (Adelpha iphiclus) and...

Alzheimer’s disease is a neurodegenerative disease characterized by the impairment of cognitive function and loss of memory, affecting millions of individuals worldwide. With the dramatic increase in the prevalence of Alzheimer’s disease, it is expected to impose extensive public health and economic burden. However, this burden is particularly heavy on the caregivers of Alzheimer’s disease patients eliciting neuropsychiatric symptoms that include mood swings, hallucinations, and depression. Interestingly, these neuropsychiatric symptoms are shared across symptoms of...

Animal pollination is critical for maintaining the reproduction and genetic diversity of many plant species, especially those in tropical ecosystems. Despite the threat to pollination posed by tropical deforestation, it remains an understudied process. In particular, little is known about these dynamics in multi-paternal, successional plant species whose fruits can contain substantial genetic diversity. Given the importance of successional plants in reforestation, quantifying the factors that impact their reproduction is essential for understanding plant gene...

Background: South Africa has the highest tuberculosis incidence globally (781/100,000), with an estimated 4.3% of cases being rifampicin resistant (RR). Control and elimination strategies will require detailed spatial information to understand where drug-resistant tuberculosis exists and why it persists in those communities. We demonstrate a method to enable drug-resistant tuberculosis monitoring by identifying high-burden communities in the Western Cape Province using routinely collected laboratory data. Methods and findings: We retrospectively identified cases of microbiologically confirmed...

PREMISE OF THE STUDY: Climate-driven changes in phenology are substantially affecting ecological relationships and ecosystem processes. The role of variation among species has received particular attention; for example, variation among species’ phenological responses to climate can disrupt trophic interactions and can influence plant performance. Variation within species in phenological responses to climate, however, has received much less attention, despite its potential role in ecological interactions and local adaptation to climate change. METHODS: We constructed three...

Dairy products exhibit several physical properties that are crucial to define whether we like the food or not: firmness, creaminess, thickness, or lightness. Viscosity changes the flow properties of food and influences the appearance and the consistency of a product; this control variable is important in most production stages—manufacture, processing, and storage. Viscosity of heterogeneous products at a given temperature depends on its composition and physical state of its substances. Although rheology provides a method...

Objective: To assess the association of early morning serum cortisol with cognitive performance and brain structural integrity in community-dwelling young and middle-aged adults without dementia. Methods: We evaluated dementia-free Framingham Study (Generation 3) participants (mean age 48.5 years; 46.8% men), who underwent cognitive testing for memory, abstract reasoning, visual perception, attention, and executive function (n= 2231), and brain MRI (n=2018) to assess total white matter, lobar gray matter, and white matter hyperintensity volumes and fractional...