Digital Commons Network^™

Developments In Agricultural Soil Quality And Health: Reflections By The Research Committee On Soil Organic Matter Management, Michelle M. Wander, Larry J. Cihacek, Mark Coyne, Rhae A. Drijber, Julie M. Grossman, Jessica L. M. Gutknecht, William R. Horwath, Sindhu Jagadamma, Daniel C. Olk, Matt Ruark, Sieglinde S. Snapp, Lisa K. Tiemann, Ray Well, Ronald F. Turco

Department of Agronomy and Horticulture: Faculty Publications

The North Central Education and Research Activity Committee (NCERA-59) was formed in 1952 to address how soil organic matter formation and management practices affect soil structure and productivity. It is in this capacity that we comment on the science supporting soil quality and associated soil health assessment for agricultural lands with the goal of hastening progress in this important field. Even though the suite of soil quality indicators being applied by U.S. soil health efforts closely mirrors the “minimum data set” we developed and recommended in the mid-1990s, we question whether the methods or means for their selection and development …

Predicting Soil Wind Erosion Potential Under Different Corn Residue Management Scenarios In The Central Great Plains, M. K. Rakkar, Humberto Blanco-Canqui, J. Tatarko

Department of Agronomy and Horticulture: Faculty Publications

Various models and simplified equations are available to predict wind erosion potential. However, their performance can be often site-specific, depending on soil characteristics and agronomic practices, warranting sitespecific model validations. Thus, in this study, we 1) validated the wind erodible fraction (WEF) predictive equations by Fryrear et al. (1994) and López et al. (2007) and 2) estimated the total soil loss with the Singleevent Wind Erosion Evaluation Program (SWEEP) using 3-yr measured data from six experiments located across a precipitation gradient in the central Great Plains. Each site had three corn (Zea mays L.) residue removal treatments: control (no …

Utilizing Trait Networks And Structural Equation Models As Tools To Interpret Multi‑Trait Genome‑Wide Association Studies, Mehdi Momen, Malachy T. Campbell, Harkamal Walia, Gota Morota

Department of Agronomy and Horticulture: Faculty Publications

Background: Plant breeders seek to develop cultivars with maximal agronomic value, which is often assessed using numerous, often genetically correlated traits. As intervention on one trait will affect the value of another, breeding decisions should consider the relationships among traits in the context of putative causal structures (i.e., trait networks). While multi-trait genome-wide association studies (MTM-GWAS) can infer putative genetic signals at the multivariate scale, standard MTM-GWAS does not accommodate the network structure of phenotypes, and therefore does not address how the traits are interrelated. We extended the scope of MTM-GWAS by incorporating trait network structures into GWAS using structural …

Joint Use Of Genome, Pedigree, And Their Interaction With Environment For Predicting The Performance Of Wheat Lines In New Environments, Réka Howard, Daniel Gianola, Osval Montesinos-Lopez, Philomin Juliana, Ravi Singh, Jesse Poland, Sandesh Shrestha, Paulino Pérez-Rodriguez, José Crossa, Diego Jarquin

Department of Agronomy and Horticulture: Faculty Publications

Genome-enabled prediction plays an essential role in wheat breeding because it has the potential to increase the rate of genetic gain relative to traditional phenotypic and pedigree-based selection. Since the performance of wheat lines is highly influenced by environmental stimuli, it is important to accurately model the environment and its interaction with genetic factors in prediction models. Arguably, multi-environmental best linear unbiased prediction (BLUP) may deliver better prediction performance than single-environment genomic BLUP. We evaluated pedigree and genome-based prediction using 35,403 wheat lines from the Global Wheat Breeding Program of the International Maize and Wheat Improvement Center (CIMMYT). We implemented …

A World Of Cobenefits: Solving The Global Nitrogen Challenge, Benjamin Z. Houlton, Maya Almaraz, Viney Aneja, Amy T. Austin, Edith Bai, Kenneth G. Cassman, Jana E. Compton, Eric A. Davidson, Jan Willem Erisman, James N. Galloway, Baojing Gu, Guolin Yao, Luiz A. Martinelli, Kate Scow, William H. Schlesinger, Thomas P. Tomich, Chao Wang, Xin Zhang

Department of Agronomy and Horticulture: Faculty Publications

Nitrogen is a critical component of the economy, food security, and planetary health. Many of the world's sustainability targets hinge on global nitrogen solutions, which, in turn, contribute lasting benefits for (i) world hunger; (ii) soil, air, and water quality; (iii) climate change mitigation; and (iv) biodiversity conservation. Balancing the projected rise in agricultural nitrogen demands while achieving these 21st century ideals will require policies to coordinate solutions among technologies, consumer choice, and socioeconomic transformation.

History Of Grass Breeding For Grazing Lands In The Northern Great Plains Of The Usa And Canada, Kenneth P. Vogel, John Hendrickson

Department of Agronomy and Horticulture: Faculty Publications

• In the early 1930s there were millions of acres of extensively degraded grazing lands and abandoned and eroded cropland in the Northern Plains of the United States and Canada.

• Grass breeding and plant materials programs were established by both the US and Canadian governments and cooperating universities to develop revegetation materials.

• Efforts of a small number of research locations and people resulted in grass cultivars or varieties that were used to revegetate and preserve the soil on millions of acres of land.

• This is a brief history of the people, agencies, and universities that developed these …

Context-Specific Genomic Selection Strategies Outperform Phenotypic Selection For Soybean Quantitative Traits In The Progeny Row Stage, Christopher J. Smallwood, Arnold M. Saxton, Jason D. Gillman, Hem S. Bhandari, Phillip A. Wadl, Benjamin D. Fallen, David L. Hyten, Qijian Song, Vincent R. Pantalone

Department of Agronomy and Horticulture: Faculty Publications

Evaluating different breeding selection strategies for relative utility is necessary to choose those that maximize efficiency. Soybean [Glycine max (L.) Merr.] seed yield and fatty acid, protein, and oil contents are all commercially important traits that display complex quantitative inheritance. A soybean population consisting of 860 F₅–derived recombinant inbred lines (RILs), genotyped with 4867 polymorphic single nucleotide polymorphism (SNPs) was used to compare phenotypic and context specific genomic selection (GS) strategies. To simulate progeny rows, each RIL was grown in a single plot in 2010 in Knoxville, TN, and phenotype was recorded. A subset of 276 RILs …

Cover Crops And Corn Residue Removal: Impacts On Soil Hydraulic Properties And Their Relationships With Carbon, Michael Sindelar, Humberto Blanco-Canqui, Virginia L. Jin, Richard B. Ferguson

Department of Agronomy and Horticulture: Faculty Publications

Large-scale crop residue removal may negatively affect soil water dynamics. Integrating cover crop (CC) with crop residue management can be a strategy to offset potential adverse effects of residue removal. We studied: (i) the impact of corn (Zea mays L.) residue removal (56%) with and without the use of winter rye (Secale cereale L.) CC on soil hydraulic properties, (ii) whether CC would ameliorate residue removal effects on hydraulic properties, and (iii) relationships of hydraulic properties with soil organic C (SOC) and other properties under irrigated no-till continuous corn on a silt loam in south central Nebraska after …

Predicting Longitudinal Traits Derived From High-Throughput Phenomics In Contrasting Environments Using Genomic Legendre Polynomials And B-Splines, Mehdi Momen, Malachy T. Campbell, Harkamal Walia, Gota Morota

Department of Agronomy and Horticulture: Faculty Publications

Recent advancements in phenomics coupled with increased output from sequencing technologies can create the platform needed to rapidly increase abiotic stress tolerance of crops, which increasingly face productivity challenges due to climate change. In particular, high-throughput phenotyping (HTP) enables researchers to generate large-scale data with temporal resolution. Recently, a random regression model (RRM) was used to model a longitudinal rice projected shoot area (PSA) dataset in an optimal growth environment. However, the utility of RRM is still unknown for phenotypic trajectories obtained from stress environments. Here, we sought to apply RRM to forecast the rice PSA in control and water-limited …

Shifting Avian Spatial Regimes In A Changing Climate, Caleb P. Roberts, Craig R. Allen, David G. Angeler, Dirac Twidwell

Department of Agronomy and Horticulture: Faculty Publications

In the present era of rapid global change, development of early warnings of ecological regime shifts is a major focus in ecology. Identifying and tracking shifts in spatial regimes is a new approach with potential to enhance understanding of ecological responses to global change. Here, we show strong directional non-stationarity of spatial regimes identified by avian community body mass data. We do this by tracking 46 years of avian spatial regime movement in the North American Great Plains. The northernmost spatial regime boundary moved >590 km northward, and the southernmost boundary moved >260 km northward. Tracking spatial regimes affords decadal …

The Mitochondrial Genome Of Eleusine Indica And Characterization Of Gene Content Within Poaceae, Nathan D. Hall, Hui Zhang, Jeffrey P. Mower, Joseph Scott Mcelroy, Leslie R. Goertzen

Department of Agronomy and Horticulture: Faculty Publications

Plant mitochondrial (mt) genome assembly provides baseline data on size, structure, and gene content, but resolving the sequence of these large and complex organelle genomes remains challenging due to fragmentation, frequent recombination, and transfers of DNA from neighboring plastids. Themt genome for Eleusine indica (Poaceae: goosegrass) is comprehensibly analyzed here, providing key reference data for an economically significant invasive species that is also the maternal parent of the allotetraploid crop Finger millet (Eleusine coracana). The assembled E. indica genome contains 33 protein coding genes, 6 rRNA subunits, 24 tRNA, 8 large repetitive regions 15 kb of transposable elements across a …

Genetic Diversity And Population Structure Of A Camelina Sativa Spring Panel, Zinan Luo, Jordan Brock, John M. Dyer, Toni Kutchan, Daniel P. Schachtman, Megan Augustin, Yufeng Ge, Noah Fahlgren, Hussein Abdel-Haleem

Department of Agricultural and Biological Systems Engineering: Faculty Publications

There is a need to explore renewable alternatives (e.g., biofuels) that can produce energy sources to help reduce the reliance on fossil oils. In addition, the consumption of fossil oils adversely affects the environment and human health via the generation of waste water, greenhouse gases, and waste solids. Camelina sativa, originated from southeastern Europe and southwestern Asia, is being re-embraced as an industrial oilseed crop due to its high seed oil content (36–47%) and high unsaturated fatty acid composition (>90%), which are suitable for jet fuel, biodiesel, high-value lubricants and animal feed. C. sativa’s agronomic advantages include …

Nucleic Acid Delivery To Mesenchymal Stem Cells: A Review Of Nonviral Methods And Applications, Andrew Hamann, Albert Nguyen, Angela K. Pannier

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Background: Mesenchymal stem cells (MSCs) are multipotent stem cells that can be isolated and expanded from many tissues, and are being investigated for use in cell therapies. Though MSC therapies have demonstrated some success, none have been FDA approved for clinical use. MSCs lose stemness ex vivo, decreasing therapeutic potential, and face additional barriers in vivo, decreasing therapeutic efficacy. Culture optimization and genetic modification of MSCs can overcome these barriers. Viral transduction is efficient, but limited by safety concerns related to mutagenicity of integrating viral vectors and potential immunogenicity of viral antigens. Nonviral delivery methods are safer, though limited …

Chronic Alcohol Exposure Alters Circulating Insulin And Ghrelin Levels: Role Of Ghrelin In Hepatic Steatosis, Karuna Rasineni, Paul G. Thomes, Jacy L. Kubik, Edward N. Harris, Kusum K. Kharbanda, Carol A. Casey

Department of Biochemistry: Faculty Publications

Fatty liver is the earliest response of the liver to excessive ethanol consumption. Central in the development of alcoholic steatosis is increased mobilization of nonesterified free fatty acids (NEFAs) to the liver from the adipose tissue. In this study, we hypothesized that ethanol-induced increase in ghrelin by impairing insulin secretion, could be responsible for the altered lipid metabolism observed in adipose and liver tissue. Male Wistar rats were fed for 5–8 wk with control or ethanol Lieber-DeCarli diet, followed by biochemical analyses in serum and liver tissues. In addition, in vitro studies were conducted on pancreatic islets isolated from experimental …

Fatty Acid Transporter 2 Reprograms Neutrophils In Cancer, Filippo Veglia, Vladimir A. Tyurin, Maria Blasi, Alessandra De Leo, Andrew Kossenkov, Laxminarasimha Donthireddy, To Tsun Ki Jerrick, Zach Schug, Subhasree Basu, Fang Wang, Emanuela Ricciotti, Concetta C. Dirusso, Maureen E. Murphy, Robert H. Vonderheide, Paul M. Lieberman, Charles Mulligan, Brian Nam, Neil Hockstein, Gregory Masters, Michael Guarino, Cindy Lin, Yulia Nefedova, Paul N. Black, Valerian E, Kagan, Dmitry Gabrilovich

Department of Biochemistry: Faculty Publications

Polymorphonuclear myeloid derived suppressor cells (PMN-MDSC) are pathologically activated neutrophils that are critically important for the regulation of immune responses in cancer. They contribute to the failure of cancer therapies and are associated with poor clinical outcomes. Despite the recent advances in understanding of the PMN-MDSC biology, the mechanisms responsible for pathological activation of neutrophils are not well defined, which limits selective targeting of these cells. Here, we report that mouse and human PMN-MDSC exclusively up-regulate fatty acid transporter protein 2 (FATP2). Over-expression of FATP2 in PMN-MDSC was controlled by GM-CSF, through the activation of STAT5 transcription factor. Deletion of …

Arsenite Exposure Suppresses Adipogenesis, Mitochondrial Biogenesis And Thermogenesis Via Autophagy Inhibition In Brown Adipose Tissue, Jiyoung Bae, Yura Jang, Heejeong Kim, Kalika Mahato, Cameron Schaecher, Issac M. Kim, Eunju Kim, Seung-Hyun Ro

Department of Biochemistry: Faculty Publications

Arsenite, a trivalent form of arsenic, is an element that occurs naturally in the environment. Humans are exposed to high dose of arsenite through consuming arsenite-contaminated drinking water and food, and the arsenite can accumulate in the human tissues. Arsenite induces oxidative stress, which is linked to metabolic disorders such as obesity and diabetes. Brown adipocytes dissipating energy as heat have emerging roles for obesity treatment and prevention. therefore, understanding the pathophysiological role of brown adipocytes can provide effective strategies delineating the link between arsenite exposure and metabolic disorders. Our study revealed that arsenite significantly reduced differentiation of murine brown …

Ecophysiological Determinants Of Sexual Size Dimorphism: Integrating Growth Trajectories, Environmental Conditions, And Metabolic Rates, Marie-Claire Chelini, John P. Delong, Eileen A. Hebets

Eileen Hebets Publications

Sexual size dimorphism (SSD) often results in dramatic differences in body size between females and males. Despite its ecological importance, little is known about the relationship between developmental, physiological, and energetic mechanisms underlying SSD. We take an integrative approach to understand the relationship between developmental trajectories, metabolism, and environmental conditions resulting in extreme female-biased SSD in the crab spider Mecaphesa celer (Thomisidae). We tested for sexual differences in growth trajectories, as well as in the energetics of growth, hypothesizing that female M. celer have lower metabolic rates than males or higher energy assimilation. We also hypothesized that the environment in …

The Development Of The Infews-Er: A Virtual Resource Center For Transdisciplinary Graduate Student Training At The Nexus Of Food, Energy, And Water, Luis F. Rodriguez, Anna-Maria Marshall, Dan Cotton, Richard K. Koelsch, Jacek Koziel, Deanne Meyer, Dan Steward, Jill Heemstra, Anand Padmanabahn, John Classen, Nathan J. Meyer, Benjamin L. Ruddell, Sean M. Ryan, Ximing Cai, Emad Habib, Peter D. Saundry

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Problems at the nexus of Food, Energy and Water Systems (FEWS) are among the most complex challenges we face. Spanning simple to complex temporal, geographic, social, and political framings, the questions raised at this nexus require multidisciplinary if not transdisciplinary approaches. Answers to these questions must draw from engineering, the physical and biological sciences, and the social sciences. Practical solutions depend upon a wide community of stakeholders, including industry, policymakers, and the general public. Yet there are many obstacles to working in a transdisciplinary environment: unfamiliar concepts, specialized terminology, and countless “blind” spots. Graduate education occurs in disciplinary ‘silos’, often …

Narrow Grass Hedge Effects On Microbial Transport Following Variable Applications Of Beef Cattle Manure, Lisa M. Durso, John E. Gilley, Dave B. Marx, Brian L. Woodbury

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The effectiveness of a 1.4 m wide grass hedge in reducing microbial transport following manure application was examined in this study. Beef cattle manure was applied to 0.75 m wide by 4.0 m long plots established on an Aksarben silty clay loam located in southeast Nebraska. Manure was added at rates required to meet none or the 1-, 2-, or 4-year nitrogen requirements for corn. The transport of phages, total coliforms, E. coli, and enterococci was measured for three 30 min simulated rainfall events, which were separated by approximately 24 h intervals. The narrow grass hedge reduced total counts of …

Identifying Advantages And Disadvantages Of Variable Rate Irrigation – An Updated Review, S. A. O’Shaughnessy, Steve R. Evett, Paul D. Colaizzi, Manuel A. Andrade, Thomas H. Marek, Derek M. Heeren, Freddie R. Lamm, Jacob L. Larue

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Variable rate irrigation (VRI) sprinklers on mechanical move irrigation systems (center pivot or lateral move) have been commercially available since 2004. Although the number of VRI, zone or individual sprinkler, systems adopted to date is lower than expected there is a continued interest to harness this technology, especially when climate variability, regulatory nutrient management, water conservation policies, and declining water for agriculture compound the challenges involved for irrigated crop production. This article reviews the potential advantages and potential disadvantages of VRI technology for moving sprinklers, provides updated examples on such aspects, suggests a protocol for designing and implementing VRI technology …

Agenator: An Open Source Computer-Controlled Dry Aging System For Beef, Soon Kiat Lau, Felipe Azevedo Ribeiro, Jeyamkondan Subbiah, Chris R. Calkins

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Dry aging of beef is a process where beef is exposed to a controlled environment with the ultimate goal of drying the beef to improve its quality and value. Comprehensive investigations into the effects of various environmental conditions on dry aging are crucial for understanding and optimizing the process, but the lack of affordable equipment focused on data collection makes it difficult to do so. The Agenator was thus developed as an open source system with a suite of features for investigating dry aging such as: measuring and recording relative humidity, temperature, mass, air velocity, and fan rotational speed; precise …

High-Speed, High-Frequency Ultrasound, In Utero Vector-Flow Imaging Of Mouse Embryos, Jeffrey A. Ketterling, Orlando Aristizabal, Billy Y. S. Yiu, Daniel H. Turnbull, Colin K. L. Phoon, Alfred C. H. Yu, Ronald H. Silverman

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Real-time imaging of the embryonic murine cardiovascular system is challenging due to the small size of the mouse embryo and rapid heart rate. High-frequency, linear-array ultrasound systems designed for small-animal imaging provide high-frame-rate and Doppler modes but are limited in regards to the field of view that can be imaged at fine-temporal and -spatial resolution. Here, a plane-wave imaging method was used to obtain high-speed image data from in utero mouse embryos and multi-angle, vector-flow algorithms were applied to the data to provide information on blood flow patterns in major organs. An 18-MHz linear array was used to acquire plane-wave …

A Role For Nanoparticles In Treating Traumatic Brain Injury, Badrul Alam Bony, Forrest M. Kievit

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Traumatic brain injury (TBI) is one of the main causes of disability in children and young adults, as well as a significant concern for elderly individuals. Depending on the severity, TBI can have a long-term impact on the quality of life for survivors of all ages. The primary brain injury can result in severe disability or fatality, and secondary brain damage can increase the complexities in cellular, inflammatory, neurochemical, and metabolic changes in the brain, which can last decades post-injury. Thus, survival from a TBI is often accompanied by lifelong disabilities. Despite the significant morbidity, mortality, and economic loss, there …

Heterologous Expression And Functional Characterization Of A Gh10 Endoxylanase From Aspergillus Fumigatus Var. Niveus With Potential Biotechnological Application, Josman Velasco, Bianca Oliva, Evandro Jose Mulinari, Leidy Patricia Quintero, Awana Da Silva Lima, Aline Larissa Goncalves, Thiago Augusto Goncalves, Andre Damasio, Fabio Marcio Squina, Adriane Maria Ferreira Milagres, Asmaa Abdella, Mark R. Wilkins, Fernando Segato

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Xylanases decrease the xylan content in pretreated biomass releasing it from hemicellulose, thus improving the accessibility of cellulose for cellulases. In this work, an endo-β-1,4-xylanase from Aspergillus fumigatus var. niveus (AFUMN-GH10) was successfully expressed. The structural analysis and biochemical characterization showed this AFUMN-GH10 does not contain a carbohydrate-binding module. The enzyme retained its activity in a pH range from 4.5 to 7.0, with an optimal temperature at 60°C. AFUMN-GH10 showed the highest activity in beechwood xylan. The mode of action of AFUMNGH10 was investigated by hydrolysis of APTS-labeled xylohexaose, which resulted in xylotriose and xylobiose as the main products. AFUMN-GH10 …

Antibiotic Resistance Gene Profile Changes In Cropland Soil After Manure Application And Rainfall, Morgan Meyers, Lisa Durso, John E. Gilley, Heidi Waldrip, Lana Castleberry, Amy Millmier Schmidt

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Land application of manure introduces gastrointestinal microbes into the environment, including bacteria carrying antibiotic resistance genes (ARGs). Measuring soil ARGs is important for active stewardship efforts to minimize gene flow from agricultural production systems; however, the variety of sampling protocols and target genes makes it difficult to compare ARG results between studies. We used polymerase chain reaction (PCR) methods to characterize and/or quantify 27 ARG targets in soils from 20 replicate, long-term no-till plots, before and after swine manure application and simulated rainfall and runoff. All samples were negative for the 10 b-lactamase genes assayed. For tetracycline resistance, only source …

Hydrogen Peroxide Sensors For Biomedical Applications, Jakob Meier, Eric M. Hofferber, Joseph A. Stapleton, Nicole M. Iverson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Hydrogen peroxide (H2O2) is an important molecule within the human body, but many of its roles in physiology and pathophysiology are not well understood. To better understand the importance of H2O2 in biological systems, it is essential that researchers are able to quantify this reactive species in various settings, including in vitro, ex vivo and in vivo systems. This review covers a broad range of H2O2 sensors that have been used in biological systems, highlighting advancements that have taken place since 2015.

Contemporary Sexual Selection Does Not Explain Variation In Male Display Traits Among Populations, J. Colton Watts, Allissa Flynn, Brigitte Tenhumberg, Eileen Hebets

Brigitte Tenhumberg Papers

Sexual selection is widely hypothesized to facilitate the evolution of reproductive isolation through divergence in sexual traits and sexual trait preferences among populations. However, direct evidence of divergent sexual selection causing intraspecific trait divergence remains limited. Using the wolf spider Schizocosa crassipes, we characterized patterns of female mate choice within and among geographic locations and related those patterns to geographic variation in male display traits to test whether divergent sexual selection caused by mate choice explains intraspecific trait variation. We found evidence of phenotypic selection on male behavior arising from female mate choice, but no evidence that selection varied …

The Effects Of Management Practices On Grassland Birds: An Introduction To North American Grasslands And The Practices Used To Manage Grasslands And Grassland Birds, Jill A. Shaffer, John P. Delong

Papers in Ornithology

Summary

The Great Plains of North America is defined as the land mass that encompasses the entire central portion of the North American continent that, at the time of European settlement, was an unbroken expanse of primarily herbaceous vegetation. The Great Plains extend from central Saskatchewan and Alberta to central Mexico and from Indiana to the Rocky Mountains. The expanses of herbaceous vegetation are often referred to as native prairie or native grasslands. Native grasslands share the characteristics of a general uniformity in vegetation structure, dominance by grasses and forbs, a near absence of trees and shrubs, annual precipitation ranging …

Testing The Competition-Colonization Trade-Off And Its Correlations With Functional Trait Variations Among Subtropical Tree Species, Yue Bin, Guojun Lin, Sabrina E. Russo, Zhongliang Huang, Yong Shen, Honglin Cao, Juyu Lian, Wanhui Ye

School of Biological Sciences: Faculty Publications

The competition-colonization trade-off, by which species can partition spatial niches, is a potentially important mechanism allowing the maintenance of species diversity in plant communities. We examined whether there was evidence for this trade-off among tree species in a subtropical forest and how it correlated with eight functional traits. We developed and estimated a metric for colonization ability that incorporates both fecundity and seed dispersal based on seed trap data and the sizes and distributions of adult trees. Competitive ability was estimated as survival probability under high crowding conditions based on neighborhood models. Although we found no significant relationship between colonization …

Gravid Tetragnathid Spiders Show An Increased Functional Response, Mary E. Boswell, John P. Delong

School of Biological Sciences: Faculty Publications

Spiders in the genus Tetragnatha feed on emerging aquatic insects, including mosquitoes and midges, but there is little known about the foraging behavior of these spiders. We hypothesized that female spiders actively developing egg sacs would increase food consumption to provide more energy to produce and provision their eggs. We tested this hypothesis by measuring foraging rates of Tetragnatha spiders kept in jars and provisioned with different levels of midges. We then tested for a difference in the functional response of spiders that did or did not lay egg sacs in their jars. Egg-laying and non-egg-laying spiders showed significantly different …