170 Works

Data from: Population size-structure dependent fitness and ecosystem consequences in Trinidadian guppies

Ronald D. Bassar, , Michael C. Marshall, Steven A. Thomas, Alexander S. Flecker, David N. Reznick & Thomas Heatherly
1. Decades of theory and recent empirical results have shown that evolutionary, population, community and ecosystem properties are the result of feedbacks between ecological and evolutionary processes. The vast majority of theory and empirical research on these eco-evolutionary feedbacks has focused on interactions among population size and mean traits of populations. 2. However, numbers and mean traits represent only a fraction of the possible feedback dimensions. Populations of many organisms consist of different size classes...

Data from: Comparative population genomics of latitudinal variation in D. simulans and D. melanogaster

Heather E. Machado, Alan O. Bergland, Emily L. Behrman, Katherine R. O'Brien, Paul S. Schmidt & Dmitri A. Petrov
Examples of clinal variation in phenotypes and genotypes across latitudinal transects have served as important models for understanding how spatially varying selection and demographic forces shape variation within species. Here we examine the selective and demographic contributions to latitudinal variation through the largest comparative genomic study to date of Drosophila simulans and D. melanogaster, with genomic sequence data from 382 individual fruit flies, collected across a spatial transect of 19 degrees latitude and at multiple...

Data from: Evolution of the snake body form reveals homoplasy in amniote Hox gene function

Jason J. Head
Hox genes regulate regionalization of the axial skeleton in vertebrates, and changes in their expression have been proposed to be a fundamental mechanism driving the evolution of new body forms. The origin of the snake-like body form, with its deregionalized pre-cloacal axial skeleton, has been explained as either homogenization of Hox gene expression domains9, or retention of standard vertebrate Hox domains with alteration of downstream expression that suppresses development of distinct regions. Both models assume...

Data from: Phylogenetic patterns of trait and trait plasticity evolution: Insights from amphibian embryos

Rick Relyea, Patrick R. Stephens, Lisa N. Barrow, Andrew Blaustein, Paul Bradley, Julia Buck, Ann Chang, Brian I Crother, James Collins, Julia Earl, Stephanie S. Gervasi, Jason T. Hoverman, Olliver Hyman, Emily Claire Moriarty Lemmon, Thomas Luhring, Moses Michelsohn, Christopher M. Murray, Steven Price, Raymond Semlitsch, Andy Sih, Aaron Stoler, Nick VandenBroek, Alexa Warwick, Greta Wengert, John Hammond … & Aaron B. Stoler
Environmental variation favors the evolution of phenotypic plasticity. For many species, we understand the costs and benefits of different phenotypes, but we lack a broad understanding of how plastic traits evolve across large clades. Using identical experiments conducted across North America, we examined prey responses to predator cues. We quantified five life history traits and the magnitude of their plasticity for 23 amphibian species/populations (spanning three families and five genera) when exposed to no cues,...

Data from: The roles of ecology, behavior and effective population size in the evolution of a community

Chih-Ming Hung, Sergei V. Drovetski & Robert M. Zink
Organismal traits such as ecological specialization and migratory behavior may affect colonization potential, population persistence, and degree of isolation, factors that determine the composition and genetic structure of communities. However, studies focusing on community assembly rarely consider these factors jointly. We sequenced 16 nuclear and one mitochondrial genes from Caucasian and European populations of 30 forest-dwelling avian species that represent diverse ecological (specialist-generalist) and behavioral (migratory-resident) backgrounds. We tested the effects of organismal traits on...

Data from: Reflections of the social environment in chimpanzee memory: applying rational analysis beyond humans

Jeffrey R. Stevens, Julian N. Marewski, Lael J. Schooler & Ian C. Gilby
In cognitive science, the rational analysis framework allows modelling of how physical and social environments impose information-processing demands onto cognitive systems. In humans, for example, past social contact among individuals predicts their future contact with linear and power functions. These features of the human environment constrain the optimal way to remember information and probably shape how memory records are retained and retrieved. We offer a primer on how biologists can apply rational analysis to study...

Data from: Maize-nutrient response information applied across Sub-Saharan Africa

Charles S. Wortmann, Maribeth Milner, Kayuki C. Kaizzi, Maman Nouri, Athanase R. Cyamweshi, Mohammed K. Dicko, Catherine N. Kibunja, Martin Macharia, Ricardo Maria, Patson C. Nalivata, Negash Demissie, Davy Nkonde, Korodjouma Ouattara, Catherine J. Senkoro, Bitrus Dawi Tarfa & Francis M. Tetteh
The profit potential for a given investment in fertilizer use can be estimated using representative crop nutrient response functions. Where response data is scarce, determination of representative response functions can be strengthened by using results from homologous crop growing conditions. Maize (Zea mays L.) nutrient response functions were selected from the Optimization of Fertilizer Recommendations in Africa (OFRA) database of 5500 georeferenced response functions determined from field research conducted in Sub-Saharan Africa. Three methods for...

Data from: Metabolic rate is canalized in the face of variable life history and nutritional environment

Rebecca M. Clark, Anthony J. Zera & Spencer T. Behmer
Despite its central importance in organismal physiology, we have poor understanding of how metabolic rate is influenced by two key factors – food nutritional content and an organism's physiological characteristics. We examined how variation in nutrients and physiological aspects of life history affect standard metabolic rate in Gryllus firmus cricket morphs that differ dramatically in flight capability and early-age fecundity. Newly moulted female morphs were fed one of 13 diets that differed in concentrations of...

Data from: Lagged effects of early-season herbivores on valley oak fecundity

Ian S. Pearse, Kyle A. Funk, Thomas S. Kraft & Walter D. Koenig
The seasonal match between folivore and leaf phenology affects the annual success of arboreal folivore populations because many folivores exploit developing leaves, which are an ephemeral resource. One strategy for folivores to exploit early-season leaves is to anticipate their emergence. The consequence of this behavior for trees is that individuals that set leaves earlier may experience greater rates of folivore damage, with potential negative fitness consequences. To test this hypothesis, we surveyed the early-season phenology,...

Data from: Climate variability predicts thermal limits of aquatic insects across elevation and latitude

Alisha A. Shah, Brian A. Gill, Andrea C. Encalada, Alexander S. Flecker, W. Chris Funk, Juan M. Guayasamin, Boris C. Kondratieff, N. LeRoy Poff, Steven A. Thomas, Kelly R. Zamudio & Cameron K. Ghalambor
Janzen's extension of the climate variability hypothesis posits that increased seasonal variation at high latitudes should result in greater temperature overlap across elevations, and favor wider thermal breadths in temperate organisms compared to their tropical counterparts. We tested these predictions by measuring stream temperatures and thermal breadths (i.e. the difference between the critical thermal maximum and minimum) of 62 aquatic insect species from temperate (Colorado, USA) and tropical (Papallacta, Ecuador) streams spanning an elevation gradient...

Data from: Lake regionalization and diatom metacommunity structuring in tropical South America

Xavier Benito, Sherilyn C. Fritz, Miriam Steinitz-Kannan, Maria I. Vélez & Michael M. McGlue
Lakes and their topological distribution across Earth’s surface impose ecological and evolutionary constraints on aquatic metacommunities. In this study, we group similar lake ecosystems as metacommunity units influencing diatom community structure. We assembled a database of 195 lakes from the tropical Andes and adjacent lowlands (8ºN–30ºS and 58–79ºW) with associated environmental predictors to examine diatom metacommunity patterns at two different levels: taxon and functional (deconstructed species matrix by ecological guilds). We also derived spatial variables...

Data from: High soil test phosphorus effect on corn yield

Charles Wortmann, Charles Shapiro, Tim Shaver & Michael Mainz Retired
Phosphorus removal in crop harvest has increased as yields have increased. Fertilizer P use guidelines are based on calibrations often developed for much lower yield levels and may need recalibration. Corn yields may be greater with higher than recommended soil test P when springs are relatively wet and cool. Research was conducted across 12 irrigated and five rainfed siteyr in Nebraska with initial Bray-1 P ≤ 11 mg kg–1 to evaluate P application strategies for...

Using patterns in prey DNA digestion rates to quantify predator diets

Stella Uiterwaal & John DeLong
Dietary metabarcoding – the process of taxonomic identification of food species from DNA in consumer guts or feces – has been rapidly adopted by ecologists to gain insights into biocontrol, invasive species, and the structure of food webs. However, an outstanding issue with metabarcoding is the semi-quantitative nature of the data it provides: because metabarcoding is likely to produce false positives for some prey more often than for other prey, we cannot infer relative frequencies...

Trophic cascades alter eco-evolutionary dynamics and body size evolution

Thomas Luhring & John DeLong
Trait evolution in predator-prey systems can feed back to the dynamics of interacting species as well as cascade to impact the dynamics of indirectly linked species (eco-evolutionary trophic cascades; EETC). A key mediator of trophic cascades is body mass, as it both strongly influences and evolves in response to predator-prey interactions. Here we use Gillespie Eco-Evolutionary Models to explore EETCs resulting from top predator loss and mediated by body mass evolution. Our four trophic level...

Data from: Puma responses to unreliable human cues suggest an ecological trap in a fragmented landscape

Anna Nisi, John Benson & Christopher C. Wilmers
Animals’ fear of people is widespread across taxa and can mitigate the risk of human-induced mortality, facilitating coexistence in human-dominated landscapes. However, humans can be unpredictable predators and anthropogenic cues that animals perceive may not be reliable indicators of the risk of being killed. In these cases, animal fear responses may be ineffective and may even exacerbate the risk of anthropogenic mortality. Here, we explore these questions using a 10-year dataset of movement and mortality...

Pea aphid winged and wingless males exhibit reproductive, gene expression, and lipid metabolism differences

Omid Saleh Ziabari, Qingyi Zhong, Swapna Purandare, Joel Reiter, Anthony Zera & Jennifer Brisson
Alternative, intraspecific phenotypes offer an opportunity to identify the mechanistic basis of differences associated with distinctive life-history strategies. Wing dimorphic insects, in which both flight-capable and flight-incapable individuals occur in the same population, are particularly well-studied in terms of why and how the morphs trade-off flight for reproduction. Yet despite a wealth of studies examining the differences between female morphs, little is known about male differences, which could arise from different causes than those acting...

A comparative phylogenomic analysis of birds reveals heterogeneous differentiation processes among Neotropical Savannas

Cássia Alves Lima-Rezende, Gustavo S. Cabanne, Amanda Vaz Rocha, Martin Carboni, Robert M. Zink & Renato Caparroz
The main objective of this study is to evaluate biogeographic hypotheses of diversification and connection between isolated savannas north (Amazonian savannas) and south (Cerrado core) of the Amazon River. To achieve our goal, we employed genomic markers (genotyping by sequencing) to evaluate the genetic structure, population phylogenetic relationships, and historical range shifts of four Neotropical passerines with peri-Atlantic distributions: the Narrow-billed Woodcreeper (Lepidocolaptes angustirostris), the Plain-crested Elaenia (Elaenia cristata), the Grassland Sparrow (Ammodramus humeralis), and...

Data from: Increased signal complexity is associated with increased mating success

Noori Choi, Matt Adams, Kasey Fowler-Finn, Elise Knowlton, Malcolm Rosenthal, Aaron Rundus, Roger Santer, Dustin Wilgers & Eileen Hebets
The evolution of complex signaling has often been explored by testing multiple functional hypotheses that vary in their underlying assumptions about how independent signal components provide selective benefits to offset the costs of their production. In the present study, we take a different approach to exploring the function of complexity per se. We test the hypothesis that increased vibratory signal complexity – based on both proportional and temporal patterning - provides selective benefits to courting...

Phylogenomic variation at the population-species interface and assessment of gigantism in a model wolf spider genus (Lycosidae, Schizocosa)

Jason Bond, James Starrett, Ashley Bui, Rowan McGinley & Eileen Hebets
Animal body size has important evolutionary implications. The wolf spider genus Schizocosa has developed as a model for studies on courtship, with visual and vibratory signals receiving attention; however, body size has never been carefully evaluated. Although species of Schizocosa can be distinguished from their close relatives by differences in genitalic structures, male ornamentation, and behavior, some species are morphologically similar, making diagnosis, and identification difficult. Evaluation of species boundaries using genetic data across Schizocosa...

An ordinal severity scale for COVID-19 retrospective studies using electronic health record data

Maryam Khodaverdi, Bradley Price, Zachary Porterfield, Timothy Bunnell, Michael Vest, Jerrod Anzalone, Jeremy Harper, Wes Kimble, Hamidreza Moradi, Brian Hendricks, Susan Santangelo & Sally Hodder
Objectives: Although the World Health Organization (WHO) Clinical Progression Scale for COVID-19 is useful in prospective clinical trials, it cannot be effectively used with retrospective Electronic Health Record (EHR) datasets. Modifying the existing WHO Clinical Progression Scale, we developed an ordinal severity scale (OS) and assessed its usefulness in the analyses of COVID-19 patient outcomes using retrospective EHR data. Results: The data set used in this analysis consists of 2,880,456 patients. PCA of the day-to-day...

Moving Mentorship to Opportunity for Women University Presidents

Tania Carlson Reis & Marilyn L. Grady
Women remain underrepresented in U.S. university presidential positions. Mentorship is a tool used to support women in gaining access to the position. In this qualitative study, eight U.S. women university presidents of public doctoral granting universities were interviewed about their mentorship experiences. Interviews were then coded and analyzed to understand the mentorship construct. Findings from the data show an interconnection between mentorship, informal relationships, and opportunity. Participants also gained greater support from male mentors versus...

Social Media as a Source of (Dis)Connection for Queer Women of Color in Culturally-Based Sororities

Antonio Duran & Crystal Garcia

Ground Snow Loads for ASCE 7-22 – What Has Changed and Why?

Marc Maguire, Brennan Bean, James Harris, Abbie Liel & Scott Russell
The changes to the ASCE 7 ground snow load maps proposed for the 2022 edition target a uniform reliability rather than a uniform hazard – an important distinction – and are the first of their kind in ASCE 7. Previously, the ASCE 7 snow loads used a uniform-hazard 50-year mean recurrence interval (MRI) with a 1.6 load factor. The newly proposed loads directly target the safety levels stipulated in Chapter 1 of ASCE 7, resulting...

Data from: Simultaneous delimitation of species and quantification of interspecific hybridization in Amazonian peacock cichlids (genus Cichla) using multi-locus data

Stuart C. Willis, Jason Macrander, Izeni P. Farias & Guillermo Orti
BACKGROUND: Introgression likely plays a significant role in evolution, but understanding the extent and consequences of this process requires a clear identification of species boundaries in each focal group. The delimitation of species, however, is a contentious endeavor. This is true not only because of the inadequacy of current tools to identify species lineages, but also because of the inherent ambiguity between natural populations and species paradigms. The result has been a debate about the...

Data from: Pearl millet and cowpea intercrop response to applied nutrients in West Africa

Nouri Maman, Mohamed Dicko, Gonda Abdou, Zoumana Kouyate & Charles Wortmann
In the Sahel, crop production is dominated by pearl millet [Pennisetum glaucum (L.) R. Br.] cropping systems including intercropping with cowpea [Vigna unguiculata (L.) Walp]. The research objectives were to determine pearl millet sole crop (PMSC) and intercrop nutrient response functions, profit opportunities from fertilizer use, and a means of relating intercrop to PMSC response. Pearl millet–cowpea trials were conducted in Niger and Mali. The treatment structure was an incomplete factorial with five, four, and...

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  • University of Nebraska - Lincoln
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  • Institut National de la Recherche Agronomique du Niger