278 Works

Molecular Differentiation of Astragalus Species and Varieties from the Western United States: The Chloroplast DNA Bridge Between Evolution and Molecular Systematics

Marwa Neyaz, Daniel Cook & Rebecca Creamer
Locoweeds are the most widespread poisonous plant problem in the world and have been reported in the Western United States since the 1800s, causing tremendous losses in livestock. Consumption of locoweeds by grazing animals stimulates the neurological disease, locoism, characterized by weight loss, ataxia, and lack of muscular coordination. The name locoweed is used for Astragalus and Oxytropis species known to contain swainsonine, the toxic principle produced by the plant endophytic fungus Undifilum. Astragalus includes...

The Comparative Cytotoxicity of Riddelliine in Primary Mouse, Rat and Chick Hepatocytes

Bryan L. Stegelmeier, William S. Resager & Steven M. Colegate
Dehydropyrrolizidine alkaloid (DHPA) producing plants commonly poison livestock, wildlife and humans. Poisoning occurs when DHPAs are ingested as feed or food, or when they contaminate medicinal or herbal products. Direct toxicologic comparison of individual DHPAs is essential to estimate their actual health risks. This has been problematic due to varying models and difficulties in DHPA isolation or synthesis. In contrast, the macrocyclic DHPA riddelliine is readily isolated and it has been used as a benchmark...

North American Hard Yellow Liver Disease: An Old Problem Readdressed

Bryan L. Stegelmeier, Meredyth Jones, Christopher P. Womack, T. Zane Davis & Dale R. Gardner
Hard yellow liver disease or fatty cirrhosis periodically affects cattle, sheep, goats, pronghorn antelope (Antilocapra americana) and whitetail deer (Odocoileus virginianus texanus) within several Texas counties in the United States. Clinically it presents as chronic liver disease with progressive hepatic necrosis and fibrosis, icterus and liver failure. The damaged livers are yellow and many have multiple firm, often gritty foci that are scattered throughout all lobes. Early investigations included feeding studies using potential toxic plants,...

Data from: Declining demographic performance and dispersal limitation influence the geographic distribution of the perennial forb, Astragalus utahensis (fabaceae)

Kathryn C. Baer & John L. Maron
1. A central goal of ecology is understanding the determinants of species’ distributions. ‘Metapopulation’ models for the existence of distributional boundaries predict that species’ geographic ranges arise from the landscape-scale deterioration of habitat suitability towards the range edge (i.e. niche mechanisms), which simultaneously hinders demographic performance and limits dispersal to suitable habitat beyond the edge (i.e. dispersal limitation). However, few studies have examined both of these mechanisms for the same species by examining abundance and...

Data from: A combined parasitological-molecular approach for non-invasive characterization of parasitic nematode communities in wild hosts

Sarah A. Budischak, Eric P. Hoberg, Art Abrams, Anna E. Jolles & Vanessa O. Ezenwa
Most hosts are concurrently or sequentially infected with multiple parasites; thus, fully understanding interactions between individual parasite species and their hosts depends on accurate characterization of the parasite community. For parasitic nematodes, noninvasive methods for obtaining quantitative, species-specific infection data in wildlife are often unreliable. Consequently, characterization of gastrointestinal nematode communities of wild hosts has largely relied on lethal sampling to isolate and enumerate adult worms directly from the tissues of dead hosts. The necessity...

Data from: Climate, demography, and zoogeography predict introgression thresholds in Salmonid hybrid zones in Rocky Mountain streams

Michael K. Young, Daniel J. Isaak, Kevin S. McKelvey, Taylor M. Wilcox, Daniel M. Bingham, Kristine L. Pilgrim, Kellie J. Carim, Matthew R. Campbell, Matthew P. Corsi, Dona E. Horan, David L. Nagel, Michael K. Schwartz, Dona L. Horan & David E. Nagel
Among the many threats posed by invasions of nonnative species is introgressive hybridization, which can lead to the genomic extinction of native taxa. This phenomenon is regarded as common and perhaps inevitable among native cutthroat trout and introduced rainbow trout in western North America, despite that these taxa naturally co-occur in some locations. We conducted a synthetic analysis of 13,315 genotyped fish from 558 sites by building logistic regression models using data from geospatial stream...

Data from: Tracking global change using lichen diversity: towards a global-scale ecological indicator

Paula Matos, Linda Geiser, Amanda Hardman, Doug Glavich, Pedro Pinho, Alice Nunes, Amadeu M. V. M. Soares, Cristina Branquinho & Amadeu M.V.M. Soares
Lichens have been used to efficiently track major drivers of global change from the local to regional scale since the beginning of the industrial revolution (sulphur dioxide) to the present (nitrogen deposition and climate change). Currently, the challenge is to universalize monitoring methodologies to compare global change drivers’ simultaneous and independent effects on ecosystems and to assess the efficacy of mitigation measures. Because two protocols are now used at a continental scale North America (US)...

Data from: Inferring invasive species abundance using removal data from management actions

Amy J. Davis, Mevin B. Hooten, Ryan S. Miller, Matthew L. Farnsworth, Jesse Lewis, Michael Moxcey & Kim M. Pepin
Evaluation of the progress of management programs for invasive species is crucial for demonstrating impacts to stakeholders and strategic planning of resource allocation. Estimates of abundance before and after management activities can serve as a useful metric of population management programs. However, many methods of estimating population size are too labor intensive and costly to implement, posing restrictive levels of burden on operational programs. Removal models are a reliable method for estimating abundance before and...

Data from: Necrobiome framework for bridging decomposition ecology of autotrophically and heterotrophically derived organic matter

Mark Eric Benbow, Philip S. Barton, Michael D. Ulyshen, James C. Beasley, Travis L. DeVault, Michael S. Strickland, Jeffery K. Tomberlin, Heather R. Jordan & Jennifer L. Pechal
Decomposition contributes to global ecosystem function by contributing to nutrient recycling, energy flow and limiting biomass accumulation. The decomposer organisms influencing this process form diverse, complex, and highly dynamic communities that often specialize on different plant or animal resources. Despite performing the same net role, there is a need to conceptually synthesize information on the structure and function of decomposer communities across the spectrum of dead plant and animal resources. A lack of synthesis has...

Data from: Ecosystem engineering strengthens bottom-up and weakens top-down effects via trait-mediated indirect interactions

Zhiwei Zhong, Xiaofei Li, Dean Pearson, Deli Wang, Dirk Sanders, Yu Zhu & Ling Wang
Trophic interactions and ecosystem engineering are ubiquitous and powerful forces structuring ecosystems, yet how these processes interact to shape natural systems is poorly understood. Moreover, trophic effects can be driven by both density- and trait-mediated interactions. Microcosm studies demonstrate that trait-mediated interactions may be as strong as density-mediated interactions, but the relative importance of these pathways at natural spatial and temporal scales is underexplored. Here, we integrate large-scale field experiments and microcosms to examine the...

Data from: Pest tradeoffs in technology: reduced damage by caterpillars in Bt cotton benefits aphids

Steffen Hagenbucher, Felix L. Wäckers, Felix E. Wettstein, Dawn M. Olson, John R. Ruberson, Jörg Romeis & F. L. Wackers
The rapid adoption of genetically engineered (GE) plants that express insecticidal Cry proteins derived from Bacillus thuringiensis (Bt) has raised concerns about their potential impact on non-target organisms. This includes the possibility that non-target herbivores develop into pests. Although studies have now reported increased populations of non-target herbivores in Bt cotton, the underlying mechanisms are not fully understood. We propose that lack of herbivore-induced secondary metabolites in Bt cotton represents a mechanism that benefits non-target...

Data from: Native grass ground covers provide multiple ecosystem services in Californian vineyards

Kent M. Daane, Brian N. Hogg, Houston Wilson & Glenn Y. Yokota
1. The mechanisms responsible for the success or failure of agricultural diversification are often unknown. Most studies of arthropod pest management focus on enhancing the effectiveness of natural enemies, but non-crop plants can also improve or hamper pest suppression by changing the host quality of crop plants by reducing or adding available soil nutrients or water. Native perennial ground covers may provide resources and long-term habitat to resident natural enemies and be more compatible than...

Data from: Studying long-term, large-scale grassland restoration outcomes to improve seeding methods and reveal knowledge gaps

Matthew J. Rinella, Erin K. Espeland & Bruce J. Moffatt
Studies are increasingly investigating effects of large-scale management activities on grassland restoration outcomes. These studies are providing useful comparisons among currently used management strategies, but not the novel strategies needed to rapidly improve restoration efforts. Here we illustrate how managing restoration projects adaptively can allow promising management innovations to be identified and tested. We studied 327 Great Plains fields seeded after coal mining. We modelled plant responses to management strategies to identify the most effective...

Data from: Minimally invasive collection of adipose tissue facilitates the study of eco-physiology in small-bodied mammals

Jeff Clerc, Theodore J. Weller, Jeffrey B. Schineller & Joseph M. Szewczak
Adipose tissue is the primary fuel storage for vertebrates and is an important component of energy budgets during periods of peak energetic demands. Investigating the composition of adipose tissue can provide information about energetics, migration, reproduction and other life-history traits. Until now, most field methods for sampling adipose tissue of small-bodied vertebrates have been destructive. Therefore, investigations of adipose tissue in small-bodied vertebrates have been limited in their broadscale application. We developed a field-ready micro-adipose...

Data from: Machine learning for characterization of insect vector feeding

Denis S. Willett, Justin George, Nora S. Willett, Lukasz L. Stelinski & Stephen L. Lapointe
Insects that feed by ingesting plant and animal fluids cause devastating damage to humans, livestock, and agriculture worldwide, primarily by transmitting pathogens of plants and animals. The feeding processes required for successful pathogen transmission by sucking insects can be recorded by monitoring voltage changes across an insect-food source feeding circuit. The output from such monitoring has traditionally been examined manually, a slow and onerous process. We taught a computer program to automatically classify previously described...

Data from: A comparison of individual-based genetic distance metrics for landscape genetics

Andrew J. Shirk, Erin L. Landguth & Samuel A. Cushman
A major aim of landscape genetics is to understand how landscapes resist gene flow and thereby influence population genetic structure. An empirical understanding of this process provides a wealth of information that can be used to guide conservation and management of species in fragmented landscapes, and also to predict how landscape change may affect population viability. Statistical approaches to infer the true model among competing alternatives are based on the strength of the relationship between...

Conflicting signal in transcriptomic markers leads to a poorly resolved backbone phylogeny of Chalcidoid wasps

Junxia Zhang, Amelia R.I. Lindsey, Ralph S. Peters, John M. Heraty, Keith R. Hopper, John H. Werren, Ellen O. Martinson, James B. Woolley, Matt J. Yoder & Lars Krogmann
Chalcidoidea (Hymenoptera) are a megadiverse superfamily of wasps with astounding variation in both morphology and biology. Most species are parasitoids and important natural enemies of insects in terrestrial ecosystems. In this study, we explored a transcriptome-based phylogeny of Chalcidoidea and found that poorly resolved relationships could only be marginally improved by adding more genes (a total of 5,591) and taxa (a total of 65), proof-checking for errors of homology and contamination, and decreasing missing data....

Genomics confirms surprising ecological divergence and isolation in an endangered butterfly

Julian Dupuis, Scott Geib, Kendall Osborne & Daniel Rubinoff
Phylogeographic patterns in phytophagous organisms are often contextualized in light of geographic isolation and ecological (host, habitat) specialization. However, assessing the relative impact of these phenomena is not straightforward, even in areas where phylogeography is well-studied, such as the California Floristic Province. Here, we use genome-wide markers to elucidate population genomic and phylgeographic patterns for a group of monophytophagous butterflies in southern California. This group is of high conservation interest because it includes the El...

Microclimate temperatures impact nesting preference in Megachile rotundata

Elisabeth Wilson, Claire Murphy, Joseph Rinehart, George Yocum & Julia Bowsher
The temperature of the nest influences fitness in cavity-nesting bees. Females may choose 14 nest cavities that mitigate their offspring’s exposure to stressful temperatures. This study aims to 15 understand how cavity temperature impacts the nesting preference of the solitary bee Megachile 16 rotundata under field conditions. We designed and 3D printed nest boxes that measured the 17 temperatures of 432 cavities. Nest boxes were four-sided with cavity entrances facing northeast, 18 northwest, southeast, and...

Tracking invasions of a destructive defoliator, the gypsy moth (Erebidae: Lymantria dispar): population structure, origin of intercepted specimens, and Asian introgression into North America

Yunke Wu, Steven Bogdanowicz, Jose Andres, Kendra Vieira, Baode Wang, Allard Cossé & Scott Pfister
Genetic data can help elucidate the dynamics of biological invasions, which are fueled by the constant expansion of international trade. The introduction of European gypsy moth (Lymantria dispar dispar) into North America is a classic example of human-aided invasion that has caused tremendous damage to North American temperate forests. Recently, the even more destructive Asian gypsy moth (mainly L. d. asiatica and L. d. japonica) has been intercepted in North America, mostly transported by cargo...

Lower soil carbon stocks in exotic vs. native grasslands are driven by carbonate losses

Brian J. Wilsey, Xia Xu, H. Wayne Polley, Kirsten Hofmockel & Steven J. Hall
Global change includes invasion by exotic (non-native) plant species and altered precipitation patterns, and these factors may affect terrestrial carbon (C) storage. We measured soil C changes in experimental mixtures of all exotic or all native grassland plant species under two levels of summer drought stress (0 and +128 mm). After eight years, soils were sampled in 10 cm increments to 100 cm depth to determine if soil C differed among treatments in deeper soils....

Trade-offs between seed size and biotic interactions contribute to coexistence of co-occurring species that vary in fecundity

John Maron, Philip Hahn, Kayrn Hajek & Dean Pearson
Despite theoretical advances, the ecological factors and functional traits that enable species varying in seed size and fecundity to coexist remain unclear. Given inherent fecundity advantages, why don’t small-seeded species dominate communities? In perennial grasslands, we evaluated whether small-seeded species are less tolerant of competition from the community dominant bunchgrass than large-seeded species but also less vulnerable to seed predation by mice. We also explored whether trade-offs involving competitive tolerance include two other functional traits,...

Data from: Evidence for spatial clines and mixed geographic modes of speciation for North American cherry-infesting Rhagoletis (Diptera:Tephritidae) flies

Meredith Doellman, Gilbert Saint Jean, Scott Egan, Thomas Powell, Glen Hood, Hannes Schuler, Daniel Bruzzese, Mary Glover, James Smith, Wee Yee, Robert Goughnour, Juan Rull, Martin Aluja & Jeffrey Feder
An important criterion for understanding speciation is the geographic context of population divergence. Three major modes of allopatric, parapatric, and sympatric speciation define the extent of spatial overlap and gene flow between diverging populations. However, mixed modes of speciation are also possible, whereby populations experience periods of allopatry, parapatry, and/or sympatry at different times as they diverge. Here, we report clinal patterns of variation for 21 nuclear-encoded microsatellites and a wing spot phenotype for cherry-infesting...

Data from: Dominant bee species and floral abundance drive parasite temporal dynamics in plant-pollinator communities

Peter Graystock, Wee Hao Ng, Kyle Parks, Amber D. Tripodi, Paige A. Muñiz, Ashley A. Fersch, Christopher R. Myers, Quinn S. McFrederick & Scott H. McArt
Pollinator declines can leave communities less diverse and potentially at increased risk to infectious diseases. Species-rich plant and bee communities have high species turnover, making the study of disease dynamics challenging. To address how temporal dynamics shape parasite prevalence in plant and bee communities, we screened >5,000 bees and flowers through an entire growing season for five common bee microparasites (Nosema ceranae, N. bombi, Crithidia bombi, C. expoeki and neogregarines). Over 110 bee species and...

Data from: Introduced beaver improve growth of non–native trout in Tierra del Fuego, South America

Ivan Arismendi, Brooke Penaluna & Carlos Jara
Species introductions threaten ecosystem function worldwide and interactions among introduced species may amplify their impacts. Effects of multiple invasions are still poorly studied and often the mechanisms underlying potential interactions among invaders are unknown. Despite being a remote and well–conserved area, the southern portion of South America has been greatly impacted by invasions of both the American Beaver (Castor canadensis) and Brown Trout (Salmo trutta fario). Here, we compared growth, condition, diet, and stable isotopes...

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