100 Works

Data from: Bean yield and economic response to fertilizer in eastern and southern Africa

K. C. Kaizzi, A. R. Cyamweshi, C. N. Kibunja, C. Senkoro, D. Nkonde, R. Maria, C. S. Wortmann, L Nabahungu & Charles Wortmann
Bean (Phaseolus vulgaris L.) is important in sub-Saharan Africa for human dietary protein. Low yields are attributed to biotic and abiotic constraints including inadequate nutrient availability. Research was conducted to determine nutrient response functions for bean production areas of Kenya, Mozambique, Rwanda, Tanzania, and Zambia. Mean trial yields ranged from 0.32 to 2.60 and 1.72 to 2.89 Mg ha-1 for bush and climbing bean, respectively. Response to N was common except in Kenya and Mozambique....

Data from: Maize-nutrient response functions for Eastern and Southern Africa

Charles S. Wortmann, Catherine Senkoro, Athanase R. Cyamweshi, Catherine Kibunja, Davy Nkonde, Moses Munthali, Patson Nalivata, Léon N. Nabahungu, Kayuki Kaizzi & Charles Wortmann
Information is scarce for maize (Zea mays L.) response to nutrient application for many production areas in tropical Africa. Research was conducted to determine macronutrient response functions and to diagnose Mg–S–Zn–B deficiencies. Site–year × N-rate interactions within countries often accounted for little variation in yield relative to the N-rate effect. Country mean grain yield responses to N-rate were curvilinear to plateau, but linear in Malawi. Although mean yields differed, the response to N was similar...

Data from: Fire, grazing, and climate shape plant-grasshopper interactions in a tallgrass prairie

Ellen A.R. Welti, Fan Qiu, Hannah M. Tetreault, Mark Ungerer, John Blair, Anthony Joern & Ellen A. R. Welti
1. Species interactions are integral to ecological community function and the structure of species interactions has repercussions for the consequences of species extinctions. Few studies have examined the role of environmental factors in controlling species interaction networks across time. 2. We examined variation in plant-grasshopper network structural properties in response to three major grassland drivers: periodic fire, ungulate grazing and climate. 3. We sequenced a plant barcoding gene from extracted grasshopper gut contents to characterize...

Data from: Sex-specific and individual preferences for hunting strategies in white sharks

Alison V. Towner, Vianey Leos-Barajas, Roland Langrock, Robert S. Shick, Malcolm J. Smale, Tami Kaschke, Oliver J.D. Jewell, Yannis P. Papastamatiou, Robert S. Schick & Oliver J. D. Jewell
Fine-scale predator movements may be driven by many factors including sex, habitat, and distribution of resources. There may also be individual preferences for certain movement strategies within a population which can be hard to quantify. Within top predators, movements are also going to be directly related to the mode of hunting; for example sit-and-wait or actively searching for prey. Although there is mounting evidence that different hunting modes can cause opposing trophic cascades, there has...

Data from: Wheat nutrient response functions for the East Africa highlands

Athanase R. Cyamweshi, Leon N. Nabahungu, Catherine J. Senkoro, Catherine Kibunja, Athanase Mukuralinda, Kayuki C. Kaizzi, Simon M. Mvuyekure, John Kayumba, Keziah W. Ndungu-Magiroi, Mary N. Koech, Charles S. Wortmann & Charles Wortmann
Wheat (Triticum æstivum L.) is an important East Africa highland crop but yields are low. Information is scarce for optimization of fertilizer use. Research was conducted to determine yield response functions for N, P and K, and to diagnose Mg–S–Zn–B deficiencies. The average grain yield increase in Rwanda due to N application was 1.5 Mg ha−1 with a mean economically optimal rate (EOR) of 68 kg ha−1 N. In Kenya and Tanzania, yield was increased...

Data from: Phytophagous insect oviposition shifts in response to probability of flower abortion owing to the presence of basal fruits

Shivani Jadeja & Brigitte Tenhumberg
Phytophagous insects use a wide-range of indicators or associated cues to avoid laying eggs in sites where offspring survival is low. For insects that lay eggs in flowers, these unsuitable sites may be created by the host plant’s resource allocation to flowers. In the sequentially flowering host plant, Yucca glauca, late-opening distal flowers are more likely to be aborted in the presence of already-initiated basal fruits because they are strong resource sinks. If flowers are...

Data from: Hybridization and reproductive isolation between diploid Erythronium mesochoreum and its tetraploid congener E. albidum (Liliaceae)

Kathy Roccaforte, Sabrina E. Russo & Diana Pilson
Polyploidy has played an important role in angiosperm diversification, but how polyploidy contributes to reproductive isolation remains poorly understood. Most work has focused on postzygotic reproductive barriers, and the influence of ploidy differences on prezygotic barriers is understudied. To address these gaps, we quantified hybrid occurrence, interspecific self-compatibility differences, and the contributions of multiple pre- and postzygotic barriers to reproductive isolation between diploid Erythronium mesochoreum (Liliaceae) and its tetraploid congener E. albidum. Reproductive isolation between...

Data from: Cascading effects of changes in land use on the invasion of the walnut Juglans regia in forest ecosystems

Magdalena Lenda, Johannes H. Knops, Piotr Skórka, Dawid Moroń & Michał Woyciechowski
1. Plant invasions are affected by many factors that must be favourable in order for invasions to occur. Factors can be grouped into three major categories: propagule pressure, biotic factors and abiotic characteristics; all may be moderated by human activity. However, studies examining all factors simultaneously are rare, and most are limited to a single factor. This hampers our understanding of the mechanisms driving invasions. 2. In recent decades, an alien walnut (Juglans regia) has...

Data from: Effects of mistletoe (Phoradendron villosum) on California oaks

Walter D. Koenig, Johannes M.H. Knops, William J. Carmen, Mario B. Pesendorfer, Janis L. Dickinson & Johannes M. H. Knops
Mistletoes are a widespread group of plants often considered to be hemiparasitic, having detrimental effects on growth and survival of their hosts. We studied the effects of the Pacific mistletoe Phoradendron villosum, a member of a largely autotrophic genus, on three species of deciduous California oaks. We found no effects of mistletoe presence on radial growth or survivorship and detected a significant positive relationship between mistletoe and acorn production. This latter result is potentially explained...

Data from: Geo-climatic factors drive diatom community distribution in tropical South American freshwaters

Xavier Benito, Sherilyn Fritz, Miriam Steinitz-Kannan, Pedro M. Tapia, Meredith A. Kelly, Thomas V. Lowell & Sherilyn C. Fritz
1.Patterns that maintain and generate biodiversity of macro-organisms in the Neotropics are widely discussed in the scientific literature, yet the spatial ecology of microorganisms is largely unknown. The unique character of the tropical Andes and adjacent Amazon lowlands generates a wide gradient of environmental conditions to advance our understanding of what drives community assembly and diversity processes. 2.We analyzed the distribution patterns of benthic diatoms (unicellular siliceous algae) as a model group of microbial passive...

Data from: Diversification of R2R3-MYB transcription factors in the tomato family Solanaceae

Daniel J. Gates, Susan R. Strickler, Lukas A. Mueller, Bradley J. S. C. Olson & Stacey D. Smith
MYB transcription factors play an important role in regulating key plant developmental processes involving defense, cell shape, pigmentation, and root formation. Within this gene family, sequences containing an R2R3 MYB domain are the most abundant type and exhibit a wide diversity of functions. In this study, we identify 559 R2R3 MYB genes using whole genome data from four species of Solanaceae and reconstruct their evolutionary relationships. We compare the Solanaceae R2R3 MYBs to the well-characterized...

Data from: Energy demand and the context-dependent effects of genetic interactions underlying metabolism

Luke A. Hoekstra, Cole R. Julick, Katelyn M. Mika & Kristi L. Montooth
Genetic effects are often context-dependent, with the same genotype differentially affecting phenotypes across environments, life stages, and sexes. We used an environmental manipulation designed to increase energy demand during development to investigate energy demand as a general physiological explanation for context-dependent effects of mutations, particularly for those mutations that affect metabolism. We found that increasing the period during which Drosophila larvae are active during development phenocopies a temperature-dependent developmental delay in a mitochondrial-nuclear genotype with...

Data from: Extreme prescribed fire during drought reduces survival and density of woody resprouters

Dirac Twidwell, William E. Rogers, Carissa L. Wonkka, Taylor Jr, Charles A., Urs P. Kreuter & Charles A. Taylor
Management intervention in ecosystems with degraded environmental services requires innovative resource management strategies that go beyond conventional restoration and conservation practices. We established a unique study that experimentally targeted extreme fire conditions during drought in humid subtropical and semiarid ecoregions. In the southern Great Plains of North America, conventional restoration and conservation practices have been either historically ineffective or economically cost prohibitive at restoring grass-dominated ecosystems following conversion to resprouting shrublands. Our aim was to...

Data from: Genomic analysis and prediction within a US public collaborative winter wheat regional testing nursery

Trevor W. Rife, Robert A. Graybosch & Jesse A. Poland
The development of inexpensive, whole-genome profiling enables a transition to allele-based breeding using genomic prediction models. These models consider alleles shared between lines to predict phenotypes and select new lines based on estimated breeding values. This approach can leverage highly-unbalanced datasets common to breeding programs. The Southern Regional Performance Nursery (SRPN) is a public nursery established by the USDA-ARS in 1931 to characterize performance and quality of near-release wheat varieties from breeding programs in the...

Data from: Spatial and temporal unpredictability of colony size in cliff swallows across 30 years

Charles R. Brown, Mary B Brown, Erin A. Roche & Mary Bomberger Brown
Most colonially breeding animals occupy colonies that range in size from a few pairs to thousands of individuals, but the causes of colony size variation are largely unknown. Three general hypotheses are: (1) that variation in colony size is maintained by fluctuating selection via spatial and temporal changes in fitness associated with different colony sizes; (2) that colony formation reflects heterogeneity in habitat, with some sites having resources to support more individuals than others; and...

Data from: Modification of wheat gluten for improvement of binding capacity with keratin in hair

Shukun Wang, Danyang Meng, Sisi Wang, Zhong Zhang, Ruijin Yang & Wei Zhao
In this study, enzymatic hydrolysis and cationization with epoxypropyldodecyldimethylammonium chloride of wheat protein, an economic protein complex containing great amount of disulfide bonds, were conducted to improve properties such as solubility and disassociation behaviour for recovery of damaged hair when used in shampoo. The optimal conditions for enzymatic hydrolysis were pH 8.2, 55°C with Alcalase for 60 min. After the selected hydrolysis, the degree of hydrolysis, nitrogen solubility index, foaming capacity index, foam stability index,...

Data from: High-yielding corn response to applied phosphorus, potassium, and sulfur in Nebraska

C. S. Wortmann, A. R. Dobermann, R. B. Ferguson, G. W. Hergert, C. A. Shapiro, D. D. Tarkalson & D. T. Walters
Nutrient management recommendations may change as yield levels and efficiency of crop production increase. Recommendations for P, K, and S were evaluated using results from 34 irrigated corn (Zea mays L.) trials conducted in diverse situations across Nebraska. The mean yield was 14.7 Mg ha−1 with adequate fertilizer applied. The median harvest index values were 0.52, 0.89, 0.15, and 0.56 for biomass, P, K, and S, respectively. Median grain yields were 372, 49, and 613...

Data from: Genomic variation across two barn swallow hybrid zones reveals traits associated with divergence in sympatry and allopatry

Elizabeth S.C. Scordato, Matthew R. Wilkins, Georgy Semenov, Alexander S. Rubtsov, Nolan C. Kane, Rebecca J. Safran & Elizabeth S. C. Scordato
Hybrid zones are geographic regions where isolating barriers between divergent populations are challenged by admixture. Identifying factors that facilitate or inhibit hybridization in sympatry can illuminate the processes that maintain those reproductive barriers. We analyzed patterns of hybridization and phenotypic variation across two newly-discovered hybrid zones between three subspecies of barn swallow (Hirundo rustica). These subspecies differ in ventral coloration and wing length, traits that are targets of sexual and natural selection, respectively, and are...

Data from: Modeled and measured ecosystem respiration in maize–soybean systems over 10 years

Ming Zhan, Adam J. Liska, Anthony L. Nguy-Robertson, Andrew E. Suyker, Matthew P. Pelton & Haishun Yang
Crop residue is an abundant resource for the potential production of biofuels, but a better understanding of its use on net carbon emissions must be developed to mitigate climate change. This analysis combines two established crop growth models (Hybrid-Maize and Soysim) with a simple soil and crop residue respiration model to estimate daily ecosystem respiration (ERe) from maize and soybean; ERe was estimated to be the sum of CO2 emissions from the oxidation of the...

Data from: Synchronized excitability in a network enables generation of internal neuronal sequences

Yingxue Wang, Zachary Roth & Eva Pastalkova
Hippocampal place field sequences are supported by sensory cues and network internal mechanisms. In contrast, sharp-wave (SPW) sequences, theta sequences, and episode field sequences are internally generated. The relationship of these sequences to memory is unclear. SPW sequences have been shown to support learning and have been assumed to also support episodic memory. Conversely, we demonstrate these SPW sequences were present in trained rats even after episodic memory was impaired and after other internal sequences...

Data from: Use of opportunistic sightings and expert knowledge to predict and compare Whooping Crane stopover habitat

Trevor J. Hefley, David M. Baasch, Andrew J. Tyre & Erin E. Blankenship
Predicting a species’ distribution can be helpful for evaluating management actions such as critical habitat designations under the U.S. Endangered Species Act or habitat acquisition and rehabilitation. Whooping Cranes (Grus americana) are one of the rarest birds in the world, and conservation and management of habitat is required to ensure their survival. We developed a species distribution model (SDM) that could be used to inform habitat management actions for Whooping Cranes within the state of...

Data from: Cryptic species diversity reveals biogeographic support for the ‘mountain passes are higher in the tropics’ hypothesis

Brian A. Gill, B. C. Kondratieff, K. L. Casner, A. C. Encalada, A. S. Flecker, D. G. Gannon, C. K. Ghalambor, J. M. Guayasamin, N. L. Poff, M. P. Simmons, S. A. Thomas, K. R. Zamudio, W. C. Funk & B. A. Gill
The ‘mountain passes are higher in the tropics’ (MPHT) hypothesis posits that reduced climate variability at low latitudes should select for narrower thermal tolerances, lower dispersal and smaller elevational ranges compared with higher latitudes. These latitudinal differences could increase species richness at low latitudes, but that increase may be largely cryptic, because physiological and dispersal traits isolating populations might not correspond to morphological differences. Yet previous tests of the MPHT hypothesis have not addressed cryptic...

Data from: Gene flow mediates the role of sex chromosome meiotic drive during complex speciation

Colin D. Meiklejohn, Emily L. Landeen, Kathleen E. Gordon, Thomas Rzatkiewicz, Sarah B. Kingan, Anthony J. Geneva, Jeffrey P. Vedanayagam, Christina A. Muirhead, Daniel Garrigan, David L. Stern, Daven C. Presgraves, Emily L Landeen, Sarah B Kingan, Anthony J Geneva, Jeffrey P Vedanayagam, Christina A Muirhead, Daven C Presgraves, David L Stern, Colin D Meiklejohn & Kathleen E Gordon
During speciation, sex chromosomes often accumulate interspecific genetic incompatibilities faster than the rest of the genome. The drive theory posits that sex chromosomes are susceptible to recurrent bouts of meiotic drive and suppression, causing the evolutionary build-up of divergent cryptic sex-linked drive systems and, incidentally, genetic incompatibilities. To assess the role of drive during speciation, we combine high-resolution genetic mapping of X-linked hybrid male sterility with population genomics analyses of divergence and recent gene flow...

Data from: Arena size modulates functional responses via behavioral mechanisms

Stella F. Uiterwaal, Anthony I. Dell, John P. DeLong, Stella F Uiterwaal & John P DeLong
Laboratory-based functional response experiments, in which foraging rates are measured across a range of resource densities, are central for determining trophic interaction strength. Historically these experiments often are performed in arbitrarily sized arenas, with larger sized organisms generally used in larger arenas. However, arena size influences foraging rates and therefore also estimates of the functional response parameters, particularly space clearance rate (attack rate). We hypothesized that non-random movement within arenas by predators and prey may...

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...

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