Digital Commons Network^™

Notes And Comments: Food Web Laws Or Niche Theory? Six Independent Empirical Tests, Kirk O. Winemiller, Eric R. Pianka, Laurie J. Vitt, Anthony Joern

School of Biological Sciences: Faculty Publications

Over the past 2 decades, empirical food webs have been shown to possess regular patterns of various kinds. Some of the first food web patterns were reported as “food web laws,” the most notable being the link-species scaling law. This empirically derived law described an inverse relationship between community species richness and web connectance (Cohen and Briand 1984; Cohen and Newman 1985). Subsequent evaluation of food webs constructed with more detailed data falsified (Warren 1989; Winemiller 1989a, 1990; Hall and Raffaelli 1991; Polis 1991) and modified (Warren 1990; Martinez 1991, 1992; Pimm et al. 1991; Martinez et al. 1999) many …

Optimal Patch-Leaving Behavior: A Case Study Using The Parasitoid Cotesia Rubecula, Brigitte Tenhumberg, Mike A. Keller, Hugh P. Possingham, Andrew J. Tyre

School of Biological Sciences: Faculty Publications

1. Parasitoids are predicted to spend longer in patches with more hosts, but previous work on Cotesia rubecula (Marshall) has not upheld this prediction. Tests of theoretical predictions may be affected by the definition of patch leaving behavior, which is often ambiguous.

2. In this study whole plants were considered as patches and assumed that wasps move within patches by means of walking or flying. Within-patch and between-patch flights were distinguished based on flight distance. The quality of this classification was tested statistically by examination of log-survivor curves of flight times.

3. Wasps remained longer in patches with higher host …

Using Cox’S Proportional Hazard Models To Implement Optimal Strategies: An Example From Behavioral Ecology, Brigitte Tenhumberg, M. A. Keller, Hugh P. Possingham

School of Biological Sciences: Faculty Publications

Simple behavioral rules, or “rules of thumb,” which lead to behavior that closely approximates an optimal strategy, have generated a lot of recent interest in the field of foraging behavior. In this paper, we derive rules of thumb from a stochastic simulation model in which the foragers behave optimally. We use a particular biological system: the patch leaving behavior of a parasitoid. We simulate parasitoids whose patch leaving behavior is determined by a stochastic dynamic programming (SDP) model, while allowing parasitoids to make mistakes in their estimation of host density when arriving in a patch We use Cox’s proportional hazards …

Mean Time To Extinction Of A Metapopulation With An Allee Effect, Chad Brassil

School of Biological Sciences: Faculty Publications

The incorporation of Allee effects into a simple metapopulation extinction model reveals a large non-linear reduction in mean time to extinction with small changes in an Allee limit. The extent of this reduction is dependent on the level of migration in the metapopulation. With small amounts of migration, small changes in the Allee limit result in large changes in the meantime to extinction. With higher levels of migration, the mean time to extinction is not as sensitive to changes in the Allee limit, becoming more similar to the single population case. The metapopulation modeled here is a set of nine …

A Cost Of Reproduction In Drosophila Melanogaster: Stress Susceptibility, Adam B. Salmon, David B. Marx, Lawrence G. Harshman

Lawrence G. Harshman Publications

Little is known about physiological mechanisms that underlie the cost of reproduction. We tested the hypothesis that stress susceptibility is a cost of reproduction. In one test of our hypothesis, Dro-sophila melanogaster females were exposed to a juvenile hormone analog (methoprene) to stimulate egg production followed by stress assays. A sterile stock of D. melanogaster was employed as a control for reproduction. Exposure of fertile females to methoprene resulted in an increase in female repro-duction and increased susceptibility to oxidative stress and starvation (compared to solvent con-trols). Sterile females did not exhibit a decrease in stress resistance. Mating also stimulated …

Female Sensitivity To Diet And Irradiation Treatments Underlies Sex-Mortality Differentials In The Mediterranean Fruit Fly, James R. Carey, Pablo Liedo, Hans-Georg Müller, Jane-Ling Wang, Brad Love, Lawrence G. Harshman, Linda Partridge

Lawrence G. Harshman Publications

Large-scale experiments on medflies that were subjected to sterilizing doses of ionizing radiation (plus intact controls) and maintained on either sugar-only or full, protein-enriched diets revealed that, whereas the mortality trajectories of both intact and irradiated male cohorts maintained on both diets are similar, the mortality patterns of females are highly variable. Mean mortality rates at 35 days in male cohorts ranged from 0.2 to 0.3 but in female cohorts ranged from 0.09 to 0.35, depending on treatment. The study reports three main influences: (a) qualitative differences exist in the sex–mortality response of medflies subjected to dietary manipulations and irradiation, …

Genetic Consequences Of Polygyny And Social Structure In An Indian Fruit Bat, Cynopterus Sphinx. I. Inbreeding, Outbreeding, And Population Subdivision, Jay F. Storz, Hari Bhat, Thomas Kunz

Jay F. Storz Publications

Population subdivision into behaviorally cohesive kin groups influences rates of inbreeding and genetic drift and has important implications for the evolution of social behavior. Here we report the results of a study designed to test the hypothesis that harem social structure promotes inbreeding and genetic subdivision in a population with overlapping generations. Genetic consequences of harem social structure were investigated in a natural population of a highly polygynous fruit bat, Cynopterus sphinx (Chiroptera: Pteropodidae), in western India. The partitioning of genetic variance within and among breeding groups was assessed using 10-locus microsatellite genotypes for 431 individually marked bats. Genetic analysis …

Clinal Variation In Body Size And Sexual Dimorphism In An Indian Fruit Bat, Cynopterus Sphinx (Chiroptera: Pteropodidae), Jay F. Storz, J. Balasingh, Hari Bhat, P. Thiruchenthil Nathan, D. Paramanantha Swami Doss, A. Antony Prakash, Thomas H. Kunz

Jay F. Storz Publications

Geographic variation in body size and sexual dimorphism of the short-nosed fruit bat (Cynopterus sphinx ) was investigated in peninsular India. Bats were sampled at 12 localities along a 1,200 km latitudinal transect that paralleled the eastern flanks of the Western Ghats. The geographic pattern of variation in external morphology of C. sphinx conforms to the predictions of Bergmann’s Rule, as indicated by a steep, monotonic cline of increasing body size from south to north. This study represents one of the first conclusively documented examples of Bergmann’s Rule in a tropical mammal and confirms that latitudinal clines in body …

A Synopsis Of The Ferns And Fern Allies Of Nebraska, With Maps Of Their Distribution, Steven B. Rolfsmeier, Robert B. Kaul, David M. Sutherland

School of Biological Sciences: Faculty Publications

An annotated list and country-by-country distribution maps are presented for the 32 species of ferns and fern allies native to Nebraska, based upon field and herbarium studies and critical evaluation of the literature. Native to the state are Isoëtes melanopoda, Selaginella rupestris, five species of Equisetum, and 25 species in 18 genera of ferns. Three native species are here verified for the first time, based upon recent collections: Matteuccia struthiopteris var. pensylvanica, Ophioglossum engelmannii, and Pellacaglabella ssp. glabella. Isoëtes melanopoda was rediscovered in 2000, the first record since 1941. Rejected are published reports of …

New Host And Geographic Records For Two Protostrongylids In Dall's Sheep, Susan J. Kutz, A. M. Veitch, Eric P. Hoberg, B. T. Elkin, Emily J. Jenkins, L. Polley

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Biodiversity survey and inventory have resulted in new information on the distribution of Protostrongylidae in Dall’s sheep (Ovis dalli dalli) from the Northwest Territories (Northwest Territories, Canada) and from Alaska (Alaska, USA). In 1998, Parelaphostrongylus odocoilei adults were found for the first time in the skeletal muscles of Dall’s sheep in the Mackenzie Mountains (Northwest Territories). Adult P. odocoilei were associated with petechial and ecchymotic hemorrhages and localized myositis; eggs and larvae in the lungs were associated with diffuse granulomatous pneumonia. Experimental infections of the slugs Deroceras laeve and Deroceras reticulatum with dorsal-spined first-stage larvae assumed to be …

Are Saudi Arabian Hospitals Prepared For The Threat Of Biological Weapons?, Manuel W. Mah, Ziad A. Memish

Saudi Medical Journal

The use of biological weapons has been recorded repeatedly in history. Until recently, biological terrorism had been little discussed or written about. However, events over the past 12 to 18 months have made it clear that likely perpetrators already envisage every possible scenario. Nations and dissident groups exist that have both the motivation and access to utilize biological weapons. In April 1994, a Russian biological weapons expert presented the conclusions of the Russian experts as to the agents most likely to be used: smallpox, anthrax, and plague. Health care workers in the Kingdom of Saudi Arabia (physicians, nurses, and emergency …

Gastrointestinal Strongyles In Wild Ruminants, Eric P. Hoberg, A. Alan Kocan, Lora G. Rickard

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Parasitologists have long studied helminth infections in wildlife species and have documented the existence of many organisms from a diversity of mammalian hosts. With this accumulation of information has come improved understanding of the significance of these organisms and the diseases they produce in their mammalian hosts. Some of the most notable examples include the metastrongyloid lungworms, Trichinella spiralis, and Elaeophora schneideri, which are covered separately in this volume. It is, however, for the group of parasites referred to as gastrointestinal nematodes that we have accumulated the most data. Only recently has progress been made in determining the …

Evaluation Of The Specificity Of Five Oligoprobes For Identification Of Cyathostomin Species From Horses, J. E. Hodgkinson, S. Love, J. Ralph Lichtenfels, S. Palfreman, Y. H. Ramsey, J. B. Matthews

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Here, we report evaluation of five oligoprobes designed from intergenic spacer (IGS) region sequences for identification of cyathostomin species. Oligoprobes were designed for identification of Cylicocyclus ashworthi, Cylicocyclus nassatus, Cylicostephanus longibursatus, Cylicostephanus goldi and a fifth probe designed to identify all members of this tribe. PCR amplification of IGS DNA from 16 cyathostomin species allowed sequence comparison and identification of four putative species-specific probes. Southern blotting of amplified products from 16 species showed that all probes were species-specific. The fifth probe recognised all 16 cyathostomin species but did not bind to members of the genus Strongylus. Furthermore, these probes …

Onchocercosis In Red Deer (Cervus Elaphus) From Spain, Mónica Santín-Durán, José M. Alunda, Eric P. Hoberg

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Onchocercosis, caused by Onchocerca flexuosa, was observed in red deer (Cervus elaphus) from Spain for the first time. Adult specimens of O. flexuosa were found in nodules in subcutaneous tissues in 42 of 125 (33%) red deer between October 1994 and September 1995; intensity of infection 6 SD was 3.93 ± 5.26 nodules per infected host. A clear seasonal pattern in the distribution of nodules was observed, with higher values of prevalence and intensity in fall and winter in contrast to spring and summer. Significant differences were found among age groups in prevalence, but not in the …

Presentation Of The Asp Distinguished Service Award To Robert L. Rausch, Eric P. Hoberg

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Over the past 50 years Robert Rausch has been at the forefront of research on the systematics, taxonomy, biogeography, epidemiology, and pathology of helminth parasites in vertebrate hosts. Research programs and projects have continually emphasized the complex interface of parasitology, sylvatic distributions of pathogens in wild mammals, and public health, whether dealing with tapeworms such as Echinococcus or Diphyllobothrium or with nematodes such as Trichinella. Most meticulous in research, contributions by Dr. Rausch have been characterized by their innovative nature, depth and scope of detail, complete articulation and examination of hypotheses, and novel insights integrating parasites and parasitism within …

Umingmakstrongylus Pallikuukensis (Nematoda: Protostrongylidae) In Gastropods: Larval Morphology, Morphometrics, And Development Rates, Susan J. Kutz, Eric P. Hoberg, Lydden Polley

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Morphological and morphometric aspects of larval development of Umingmakstrongylus pallikuukensis in Deroceras laeve and the effects of temperature on development rates in D. laeve and Deroceras reticulatum were investigated in the laboratory. Larval stages were best differentiated by separation of cuticular sheaths, tail structure, and viability following digestion. Growth in body and esophagus width was observed during the first-stage within the intermediate host, but the major increases in body length and width occurred immediately following the second molt. Larval development in D. laeve and D. reticulatum occurred more rapidly at warmer temperatures. The calculated threshold temperatures were 8.5 and 9.5 …

Ancestral Divergence, Genome Diversification, And Phylogeographic Variation In Subpopulations Of Sorbitol-Negative, Β-Glucuronidase- Negative Enterohemorrhagic Escherichia Coli O157, Jaehyoung Kim, Joseph Nietfeldt, Jingliang Ju, John Wise, Narelle Fegan, Patricia Desmarchelier, Andrew K. Benson

Department of Food Science and Technology: Faculty Publications

The O157:H7 lineage of enterohemorrhagic Escherichia coli is a geographically disseminated complex of highly related genotypes that share common ancestry. The common clone that is found worldwide carries several markers of events in its evolution, including markers for acquisition of virulence genes and loss of physiological characteristics, such as sorbitol fermentation ability and β-glucuronidase production. Populations of variants that are distinct with respect to motility and the sorbitol and β-glucuronidase markers appear to have diverged at several points along the inferred evolutionary pathway. In addition to these variants, distinct subpopulations of the contemporary non-sorbitol-fermenting, β-glucuronidase-negative O157:H7 clone were recently detected …

So You Want To Work With Wolves?, John A. Shivik

United States Department of Agriculture Wildlife Services: Staff Publications

Growing up with three older sisters was a bit like being raised by wolves. One of their favorite games was called “stop hitting yourself.” To play, I was immobilized, and then with my arms overpowered, I was forced to repeatedly pummel my own noggin while they uttered the name of the game. Watching yourself hit yourself, feeling the pain and humiliation, yet being unable to stop is somewhat like being a federal biologist working with wolves. I’ve learned humility from my experiences but also formed the opinion that if you want to work with wolves, first consider medication; if that …

Estimation Of Red-Winged Blackbird Mortality From Toxic Bait Application, James F. Glahn, Michael L. Avery

United States Department of Agriculture Wildlife Services: Staff Publications

Application of slow-acting toxic bait is one method of reducing local populations of depredating blackbirds. Estimating numbers of birds killed in such baiting operations is difficult because affected birds die off-site and are seldom recovered. We conducted bioassays and flight pen studies of red-winged blackbirds (Agelaius phoeniceus) with a slow-acting, toxic brown rice bait to determine whether bird mortality could be predicted accurately using the Poisson and binomial discrete probability distributions. Bioassays confirmed that brown rice treated with 2% (w/w) 2-chloro-p-acetotoluidide was effective as a 1-particle lethal bait for redwings. Within a 0.2-ha flight pen, we offered this …

Design Of A Laboratory Secondary Hazard Study, David A. Goldade, Peter J. Savarie, Jerome C. Hurley, Stanley A. Gaddis, John J. Johnston

United States Department of Agriculture Wildlife Services: Staff Publications

Factors influencing the design and execution of a secondary hazard study are presented using the anticoagulant rodenticide, difethialone, as a model. Frequently, regulatory agencies require a determination of the potential hazard posed to non-target species by the application of pesticides. This hazard can occur through: 1) primary hazard, direct consumption of the bait or formulation containing the pesticide, or 2) secondary hazard, indirect consumption of the pesticide via ingestion of biological matrices such as animals or plants containing pesticide residues. In making this determination, the selection of appropriate test species as well as routes and level of exposure are critical. …

Introduction To Pesticides And Wildlife, John J. Johnston

United States Department of Agriculture Wildlife Services: Staff Publications

A pesticide is a substance intended for destroying, repelling or mitigating any animal, microorganism or plant pest. While pesticides are commonly chemical agents, biological or physical agents can also be pesticides. Many people equate the term pesticide with insecticide. However, there are a plethora of pesticides for which insects are not the target pest. Examples include herbicides, fungicides, rodenticides, acaricides, larvacides, etc. Additionally, pesticides are not limited to toxicants, but also include repellents, attractants and growth regulators (1 ) .

Pesticides are nearly ubiquitous in today's world. In agriculture, insecticides, nematicides and herbicides are applied to plants and soil to …

Chlorophacinone Residues In Rangeland Rodents: An Assessment Of The Potential Risk Of Secondary Toxicity To Scavengers, Thomas M. Primus, John D. Eisemann, George H. Matschke, Craig Ramey, John J. Johnston

United States Department of Agriculture Wildlife Services: Staff Publications

Field studies were conducted in California to assess efficacy of chlorophacinone-treated steam-rolled oats for controlling rangeland rodents. An objective of these studies was to assess the potential hazards of chlorophacinone residues in rangeland rodent carcasses and livers to mammalian and avian scavengers, especially raptors. Belding's ground squirrels, valley pocket gophers and Microtus spp. carcasses collected during the efficacy studies were analyzed for chlorophacinone residues. The method limit of detection (MLOD) for liver and carcass tissue samples averaged 0.036 μg/g and 0.034 μg/g, respectively. Chlorophacinone residues in Belding's ground squirrel (n=62) liver and carcass tissue ranged from Microtus sp. (n=3) tissue …

Worms, Nematoda, Scott Lyell Gardner

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Nematodes are the most speciose phylum of metazoa on earth. Not only do they occur in huge numbers as parasites of all known animal groups, but also they are found in the soils, as parasites of plants, and in large numbers in the most extreme environments, from the Antarctic dry valleys to the benthos of the ocean. They are extremely variable in their morphological characteristics, with each group showing morphological adapta­tions to the environment that they inhabit. Soil-dwelling forms are extremely small; many marine species have long and complex setae; and parasitic species man­ifest amazingly great reproductive potential and large …

Phylogenetic Position Of Eimeria Antrozoi, A Bat Coccidium (Apicomplexa: Eimeriidae) And Its Relationship To Morphologically Similar Eimeria Spp. From Bats And Rodents Based On Nuclear 18s And Plastid 23s Rdna Sequences, Xiaomin Zhao, Donald W. Duszynski, Eric S. Loker

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Partial plastid 23S and nuclear 18S rDNA genes were amplified and sequenced from 2 morphologically similar Eimeria species, E. antrozoi from a bat (Antrozous pallidus) and E. arizonensis from deer mice (Peromyscus spp.), as well as some other Eimeria species from bats and rodents. The phylogenetic trees clearly separated E. antrozoi from E. arizonensis. The phylogenies based on plastid 23S rDNA data and combined data of both plastid and nuclear genes grouped 2 bat Eimeria and 3 morphologically similar Eimeria species from rodents into 2 separate clades with high bootstrap support (100%, 3 rodent Eimeria species; …

Phylogenetic Analysis Of The Rhabdocoela (Platyhelminthes) With Emphasis On The Neodermata And Relatives, David Zamparo, Daniel R. Brooks, Deborah A. Mclennan, Eric P. Hoberg

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Phylogenetic systematic analysis of 24 taxa representing the rhabdocoel platyhelminths, based on a suite of 89 morphological characters, produced two equally parsimonious trees, 181 steps long, with a consistency index (CI) of 0.69 and a rescaled consistency index (RCI) of 0.56, differing only with respect to that portion of the tree containing Umagillidae, Acholadidae, Graffillinae, Pseudograffillinae, Pterastericolidae and Hypoblepharinidae. Our results accommodate all previously proposed sister taxa to the Neodermata in a single clade in which ((Dalyelliidae + Temnocephalida) Typhloplanidae) is the sister group of ((Fecampiidae + Urastoma) (Udonella ((Aspidogastrea + Digenea) (Monogenea (Gyrocotylidea (Amphilinidea + Eucestoda)))))). Bootstrap …

Genomic Regions That Underlie Soybean Seed Isoflavone Content, K. Meksem, V. N. Njiti, W. J. Banz, M. J. Iqbal, My. M. Kassem, David L. Hyten, J. Yuang, T. A. Winters, D. A. Lightfoot

Department of Agronomy and Horticulture: Faculty Publications

Soy products contain isoflavones (genistein, daidzein, and glycitein)that display biological effects when ingested by humans and animals, these effects are species, dose and age dependent. Therefore, the content and quality of isoflavones in soybeans is a key to their biological effect. Our objective was to identify loci that underlie isoflavone content in soybean seeds. The study involved 100 recombinant inbred lines (RIL)fr om the cross of ‘Essex’ by ‘Forrest,’ two cultivars that contrast for isoflavone content. Isoflavone content of seeds fromeach RIL was determined by high performance liquid chromatography (HPLC). The distribution of isoflavone content was continuous and unimodal. The …

Prevalence Of Eimeria (Apicomplexa: Eimeriidae) In Reintroduced Gunnison's Prairie Dogs (Cynomys Gunnisoni), M. M. Ryan, K. H. Decker, Donald W. Duszynski

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Fecal samples from 54 Gunnison’s prairie dogs (Cynomys gunnisoni) from Albuquerque, NM were analyzed for the presence of coccidia and all were positive. They were then relocated to an abandoned prairie dog town on the Sevilleta Long Term Ecological Research (LTER) site. Six Eimeria species, E. callospermophili, E. cynomysis, E. pseudospermophili (new host record), E. spermophili, E. ludoviciani and E. vilasi (new host record) were found in Albuquerque animals, but only two species, E. callospermophili and E. vilasi were present in relocated hosts. A significant (P < 0.05) reduction was seen in the prevalence of E. vilasi (72% vs. 13%) and in the prevalence of infections …

Research Needs Concerning Non-Target Impacts Of Biological Control Introductions, K.R. Hopper

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Two workshops were held in 1999 on research needs concerning non-target impacts of biological control introductions. One took place on the Internet for 9 months, and the other in Montpellier, France, for 1 day. Altogether, over 200 researchers from over 30 countries participated, representing a wide variety of viewpoints on the issues involved. The deliberations of these workshops are summarized here. Both workshops highlighted the need for retrospective studies to: (i) identify cases of significant non-target impacts; (ii) explore mechanisms involved when such impacts are found; (iii) evaluate the reliability of host-range testing protocols; and (iv) determine whether and under …

Nutrients In Runoff Following The Application Of Swine Manure To Interrill Areas, John E. Gilley, Bahman Eghball, Brian J. Wienhold, Phillip S. Miller

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The P content of swine manure can be reduced through the addition of feed supplements or the use of selected corn hybrids. This study was conducted to compare interrill runoff losses of P and N from three soils following the application of swine manure obtained from selected diets. The soils used in this investigation included a Hersh sandy loam, Pierre silty clay, and Sharpsburg silt loam. Simulated rainfall was applied during both initial and wet runs to a soil pan on which swine manure produced from low phytate corn (LPC), phytase added to the diet (PHY), or a traditional corn …

Functional Classification Of Swine Manure Management Systems Based On Effluent And Gas Emission Characteristics, J. A. Zahn, J. L. Hatfield, D. A. Laird, T. T. Hart, Y. S. Do, A. A. Dispirito

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Gaseous emissions from swine (Sus scrofa) manure storage systems represent a concern to air quality due to the potential effects of hydrogen sulfide, ammonia, methane, and volatile organic compounds on environmnental quality and human health. The lack of knowledge concerning functional aspects of swine manure management systems has been a major obstacle in the development and optimization of emission abatement technologies for these point sources. In this study a classification system based on gas emission characteristics and effluent concentrations of total phosphorus (P) and total sulfur (S) was devised and tested on 29 swine manure management systems in …