Open Access. Powered by Scholars. Published by Universities.®

Ecology and Evolutionary Biology Commons™

Open Access. Powered by Scholars. Published by Universities.®

2009

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 61 - 90 of 292

Full-Text Articles in Ecology and Evolutionary Biology

Introduction And Spread Of Bromus Tectorum (Cheatgrass) Into Midwestern United States: Population Genetic And Evolutionary Consequences, Temsha D. Huttanus Aug 2009

Introduction And Spread Of Bromus Tectorum (Cheatgrass) Into Midwestern United States: Population Genetic And Evolutionary Consequences, Temsha D. Huttanus

Boise State University Theses and Dissertations

High propagule pressure is correlated with invasion success, and has important implications for the genetic diversity and evolutionary potential of a species in its introduced range. Here, I examine an invasive annual grass Bromus tectorum and document the population genetic consequences that resulted from multiple introductions of genotypes native to different Eurasian regions into the North American Midwest. Herbarium collections showed that B. tectorum was first recorded near-contemporaneously throughout the Midwest in the late 1800s. Allozyme diversity data from 60 populations were used to assess the origin and frequency of introductions into the Midwest. Genetic variation and structure was compared …


Predicting Leptodactylus (Amphibia, Anura, Leptodactylidae) Distributions: Broad-Ranging Versus Patchily Distributed Species Using A Presence-Only Environmental Niche Modeling Technique, Miguel Fernández, Daniel Cole, W. R. Heyer, Stephen Reichle, Rafael O. De Sá Aug 2009

Predicting Leptodactylus (Amphibia, Anura, Leptodactylidae) Distributions: Broad-Ranging Versus Patchily Distributed Species Using A Presence-Only Environmental Niche Modeling Technique, Miguel Fernández, Daniel Cole, W. R. Heyer, Stephen Reichle, Rafael O. De Sá

Biology Faculty Publications

Locality data available for many, if not most, species of Neotropical frogs are based on written descriptions of the collecting sites, not on GPS device determined coordinate data. The pre-GPS device data are imprecise relative to GPS data. Niche modeling is a powerful technique for predicting geographic distributions that provides the best results when the locality data are precise. The purpose of this study is to determine whether imprecise historical locality data are sufficient such that niche modeling techniques can yield realistic new insights to species-level distributions. Two sets of frogs of the genus Leptodactylus that have known different kinds …


Population Ecology Of The Floodplain Herb Macbridea Caroliniana (Lamiaceae) With Investigations On The Species' Habitat, Breeding System And Genetic Diversity, Katherine Weeks Aug 2009

Population Ecology Of The Floodplain Herb Macbridea Caroliniana (Lamiaceae) With Investigations On The Species' Habitat, Breeding System And Genetic Diversity, Katherine Weeks

All Dissertations

The perennial herbaceous mint Macbridea caroliniana is known from 36 locations in discrete watersheds of the Carolinas and Georgia. It is one of relatively few conspicuously flowering herbs that occupy bottomland hardwood forests. The general project goal was to gain knowledge that is applicable to the species' conservation both at the Congaree National Park (CNP) where the largest known population of this species occurs and range-wide. Specific objectives were to (1) quantify the population size and describe the distribution of M. caroliniana within CNP, and determine the extent of co-occurrence with wild hogs and the non-native Murdannia keisak; (2) identify …


The Very Basics Of Sustainability - An Alternative Viewpoint (Slides With Audio) (Large File! To Speed Up Download, Right-Click On "Download" Link To Save To Own Pc.), Jim Mcgovern Aug 2009

The Very Basics Of Sustainability - An Alternative Viewpoint (Slides With Audio) (Large File! To Speed Up Download, Right-Click On "Download" Link To Save To Own Pc.), Jim Mcgovern

Other resources

This presentation sets out the very basics of ‘sustainability’, although a definition of sustainability is not attempted. Some of the very basics are the context in which the Earth and humankind exist in space and time, the Earth’s climate, the Earth’s population and humankind’s options and choices. The author advocates keeping an open mind on all available options, including the use of oil, gas, coal, tar sands, carbon capture and sequestration, nuclear power etc., as well as the technologies that are more widely considered ‘green’. The author also argues that, in addressing the challenges that humankind faces, globally concerted effort …


Monitoring Of Heavy Metal Loading Into The Wetlands South Of Lake Victoria Basin, Nothern Tanzania, M K D Mutakyahwa, J R Ikingura, G Y S Mtui Jul 2009

Monitoring Of Heavy Metal Loading Into The Wetlands South Of Lake Victoria Basin, Nothern Tanzania, M K D Mutakyahwa, J R Ikingura, G Y S Mtui

Tanzania Journal of Science

The paper discusses sources, concentrations and physicochemical parameters of heavy metals of environmental concern in the wetlands of Lake Victoria basin in Tanzania. The metals investigated include copper (Cu), lead (Pb), zinc (Zn), cadmium (Cd), chromium (Cr), nickel (Ni), arsenic (As), manganese (Mn), cobalt (Co) and mercury (Hg). These metals are released into the wetlands via weathering and erosion of rock formations, mining operations and industrial activities, discharge of municipal and domestic waste, and use of agrochemicals. The levels of these heavy metals in soil, sediment, water, and biota differ. Wetlands impacted by gold mining activities in the South Lake …


Effects Of Selection For Cooperation And Attention In Dogs, Márta Gácsi, Paul Mcgreevy, Edina Kara, Ádám Miklósi Jul 2009

Effects Of Selection For Cooperation And Attention In Dogs, Márta Gácsi, Paul Mcgreevy, Edina Kara, Ádám Miklósi

Cooperative Behavior Collection

Background: It has been suggested that the functional similarities in the socio-cognitive behaviour of dogs and humans emerged as a consequence of comparable environmental selection pressures. Here we use a novel approach to account for the facilitating effect of domestication in dogs and reveal that selection for two factors under genetic influence (visual cooperation and focused attention) may have led independently to increased comprehension of human communicational cues.

Method: In Study 1, we observed the performance of three groups of dogs in utilizing the human pointing gesture in a two-way object choice test. We compared breeds selected to work while …


Rapid Fixation Of Non-Native Alleles Revealed By Genome-Wide Snp Analysis Of Hybrid Tiger Salamanders, Benjamin M. Fitzpatrick, Jarrett R. Johnson, D. Kevin Kump, H. Bradley Shaffer, Jeramiah J. Smith, S. Randal Voss Jul 2009

Rapid Fixation Of Non-Native Alleles Revealed By Genome-Wide Snp Analysis Of Hybrid Tiger Salamanders, Benjamin M. Fitzpatrick, Jarrett R. Johnson, D. Kevin Kump, H. Bradley Shaffer, Jeramiah J. Smith, S. Randal Voss

Biology Faculty Publications

BACKGROUND: Hybrid zones represent valuable opportunities to observe evolution in systems that are unusually dynamic and where the potential for the origin of novelty and rapid adaptation co-occur with the potential for dysfunction. Recently initiated hybrid zones are particularly exciting evolutionary experiments because ongoing natural selection on novel genetic combinations can be studied in ecological time. Moreover, when hybrid zones involve native and introduced species, complex genetic patterns present important challenges for conservation policy. To assess variation of admixture dynamics, we scored a large panel of markers in five wild hybrid populations formed when Barred Tiger Salamanders were introduced into …


Habitat-Based Intraguild Predation By Caribbean Reef Octopus Octopus Briareus On Juvenile Caribbean Spiny Lobster Panulirus Argus, Mark J. Butler Iv, Jennifer A. Lear Jul 2009

Habitat-Based Intraguild Predation By Caribbean Reef Octopus Octopus Briareus On Juvenile Caribbean Spiny Lobster Panulirus Argus, Mark J. Butler Iv, Jennifer A. Lear

Biological Sciences Faculty Publications

Intraguild predation occurs when species simultaneously compete for resources and interact as predator and prey, which describes the interaction between juvenile Caribbean spiny lobster Panulirus argus and Caribbean reef octopus Octopus briareus in the Florida Keys, USA. Octopuses are notorious predators of decapod crustaceans, and their use of crevice shelters suggests that they may also compete for shelter with their lobster prey. Lobsters use mainly chemical cues to detect and avoid octopus, so we hypothesized that the negative association between these species may be as much the consequence of avoidance of a superior competitor as it is of direct predation. …


Limnological Assistance For The Lake Mead National Recreation Area In Meeting The Challenge Of The Water 2025 Initiative: Annual Report, Period Ending July 1, 2009, Margaret N. Rees Jul 2009

Limnological Assistance For The Lake Mead National Recreation Area In Meeting The Challenge Of The Water 2025 Initiative: Annual Report, Period Ending July 1, 2009, Margaret N. Rees

Limnological Studies

Project 1: Eighteen advisory team meetings were attended this year; technical input was provided as appropriate; and summaries were prepared and delivered to Kent Turner. The SCOP Selenium Management Plan has been reviewed and a report is in preparation.

Project 2: A formal report titled, Surface Water Monitoring for Indicator Bacteria in High-use Sites of the Lake Mead National Recreation Area, was delivered in the second quarter of this year. Subsequently, a poster presentation on this topic was delivered at the Lake Mead Science Symposium and a manuscript has been prepared for submission to the journal, Lake and Reservoir Management. …


Lake Mead National Recreation Area Vegetation Monitoring And Analysis: Quarterly Progress Report, April 1, 2009 To June 30, 2009, Margaret N. Rees Jul 2009

Lake Mead National Recreation Area Vegetation Monitoring And Analysis: Quarterly Progress Report, April 1, 2009 To June 30, 2009, Margaret N. Rees

Vegetation Monitoring

Executive Summary

  • The Weed Sentry program surveyed over 187 miles (1,342 acres) of federal land by vehicle and foot in Clark County for incipient populations of exotic plants.
  • Weed Sentry staff continue to survey never before surveyed sites, and trails and regions within Upper Las Vegas Wash CTA and Sloan Canyon NCA as requested by BLM managers
  • In 2009 rare plant monitoring was completed. Data entry and analysis are in progress.


Mojave Applied Ecology Notes Summer 2009, Kevin E. Oliver, Dianne N. Bangle, E. Cayenne Engel, Lindsay P. Chiquoine, Scott R. Abella Jul 2009

Mojave Applied Ecology Notes Summer 2009, Kevin E. Oliver, Dianne N. Bangle, E. Cayenne Engel, Lindsay P. Chiquoine, Scott R. Abella

Mojave Applied Ecology Notes

BLM and wildfire protection in the Mojave, studies of the sticky ringstem flowering phenology in Lake Mead NRA, restoration work within gypsum soils, post-fire response synthesis for Mojave and Sonoran deserts


Quantification Of Bt-Endotoxin Exposure Pathways In Carabid Food Webs Across Multiple Transgenic Events, Julie A. Peterson, John J. Obrycki, James D. Harwood Jul 2009

Quantification Of Bt-Endotoxin Exposure Pathways In Carabid Food Webs Across Multiple Transgenic Events, Julie A. Peterson, John J. Obrycki, James D. Harwood

West Central Research and Extension Center, North Platte

Despite the reported specificity of Bacillus thuringiensis proteins against target pests, a number of studies have indicated that the uptake of Bt-endotoxins from bioengineered crops could have negative effects on natural enemies. It is therefore essential to quantify exposure pathways in non-target arthropod food webs across multiple transgenic events. Adult ground beetles (Coleoptera: Carabidae) were collected from transgenic corn fields expressing lepidopteran-specific Cry1Ab, coleopteran-specific Cry3Bb1, and both Cry1Ab and Cry3Bb1 (stacked event), as well as a non-transgenic isoline. Carabid gut-contents were screened for Cry1Ab Bt-endotoxin using enzyme-linked immunosorbent assay. Significant numbers of carabids tested positive for Cry1Ab from the lepidopteran-specific …


Collective Batesian Mimicry Of Ant Groups By Aggregating Spiders, Ximena J. Nelson, Robert R. Jackson Jul 2009

Collective Batesian Mimicry Of Ant Groups By Aggregating Spiders, Ximena J. Nelson, Robert R. Jackson

All Peer-Reviewed Publications

Many predators are averse to attacking ants and many palatable arthropods are Batesian mimics of ants. We considered whether aggregating Batesian mimics of ants can become more repelling to ant-averse predators by, as a group, resembling groups of ants (collective mimicry). Myrmarachne melanotarsa is a gregarious ant-like jumping spider (Salticidae) that resembles and associates with the ant Crematogaster sp. We used three large ant-averse salticids as predators in experiments. Besides M. melanotarsa and Crematogaster we used midges (Chaoborus sp.) and a small nonant-like, but gregarious, salticid (Menemerus sp.) as prey. The predators readily attacked both live midges and the nonant-like …


Pines And The Ecology Of Carnaby‘S Black-Cockatoos (Calyptorhynchus Latirostris) In The Gnangara Sustainability Strategy Area, Hugh Finn, William Stock, Leonie Valentine Jul 2009

Pines And The Ecology Of Carnaby‘S Black-Cockatoos (Calyptorhynchus Latirostris) In The Gnangara Sustainability Strategy Area, Hugh Finn, William Stock, Leonie Valentine

Research outputs pre 2011

This study examined the behavioural ecology of Carnaby‘s Black-Cockatoo in the Gnangara Sustainability Strategy study area, with a focus on habitat use of pine plantations. The study confirms that the pine is the main food source for Carnaby‘s Black-Cockatoos within the GSS area during the non-breeding season (January-June). The value of the Gnangara-Pinjar-Yanchep pine plantations as a food source for Carnaby‘s Black-Cockatoo should not be underestimated. Large congregations of birds (~3000) utilised the pine plantations for an extended period, mainly January-March but with birds continuing to feeding within the plantations through June. The pine plantations have provided an important and …


Modeling And Analysis Of Biological Populations, Joan Lubben Jul 2009

Modeling And Analysis Of Biological Populations, Joan Lubben

Department of Mathematics: Dissertations, Theses, and Student Research

Asymptotic and transient dynamics are both important when considering the future population trajectory of a species. Asymptotic dynamics are often used to determine whether the long-term trend results in a stable, declining or increasing population and even provide possible directions for management actions. Transient dynamics are important for estimating invasion speed of non-indigenous species, population establishment after releasing biocontrol agents, or population management after a disturbance like fire. We briefly describe here the results in this thesis.

(1) We consider asymptotic dynamics using discrete time linear population models of the form n(t + 1) = An(t) where …


Biotic And Abiotic Characteristics Influencing Nest Location And Trophic Relationships Of The Fungus-Growing Ant Trachymyrmex Septentrionalis (Formicidae: Attini), Jonathan Paul Howell Jul 2009

Biotic And Abiotic Characteristics Influencing Nest Location And Trophic Relationships Of The Fungus-Growing Ant Trachymyrmex Septentrionalis (Formicidae: Attini), Jonathan Paul Howell

Biological Sciences Theses & Dissertations

Trachymyrmex septentrionalis represents the only species of fungus-growing ant in the southeastern United States. T. septentrionalis cultivates a symbiotic fungus on which the ants feed. Worker ants collect plant and animal debris to feed the fungus. These ants are common in Florida, but increasingly scarce as they near the northern extent of their range in New Jersey. Colonies of T. septentrionalis occur in patches throughout Blackwater Ecological Preserve, a longleaf pine forest in southeastern Virginia. Blackwater Ecologic Preserve is a 129 hectare tract of land, located in Isle of Wight county, that is undergoing a regimen of controlled burning to …


Changing Fecundity And Reproductive Output In Females Of A Chesapeake Bay Population Of Blue Crab, Callinectes Sapidus, Shannon L. Wells Jul 2009

Changing Fecundity And Reproductive Output In Females Of A Chesapeake Bay Population Of Blue Crab, Callinectes Sapidus, Shannon L. Wells

OES Theses and Dissertations

The Chesapeake Bay blue crab, Callinectes sapidus, is an important species both ecologically and as a fishery. Fishery dependent and independent data indicate that the population declined abruptly in the mid-1990s and has remained low. Previous work prior to the decline in population abundance found a significant relationship between size and fecundity for mature females. As with many heavily fished populations, this population has experienced a reduction in the size at maturity. The objectives of this study were to reassess the fecundity of the population, determine the lipid and protein energy allocated for reproduction, and to examine the concentrations …


Effect Of The Herbivorous Channel Clinging Crab (Mithrax Spinosissimus) On Patch Reef Algal Communities In The Florida Keys, Florida (Usa), Angela M. Mojica Osorio Jul 2009

Effect Of The Herbivorous Channel Clinging Crab (Mithrax Spinosissimus) On Patch Reef Algal Communities In The Florida Keys, Florida (Usa), Angela M. Mojica Osorio

Biological Sciences Theses & Dissertations

Coral reefs worldwide are undergoing dramatic habitat modification from coral to macroalgal dominance due to water pollution, coral diseases, global. warming, and the loss of herbivores. This phase-shift bas been particularly severe on Caribbean reefs due in large measure to the decline of piscine and echinoderm grazers, whose presence appears crucial for stemming the decline of coral reefs and enhancing their resilience. Virtually unknown, however, is the role of other macrograzers in coral reef ecosystems. This is the first study to examine the feeding ecology and grazer effect of the herbivorous West Indian spider crab (Mithrax spinosissimus) on inshore patch …


Nevada Interagency Volunteer Program: Helping Hands Across Public Lands – Phase Ii: Annual Progress Report, Period Covering July 1, 2008 - June 30, 2009, Margaret N. Rees Jun 2009

Nevada Interagency Volunteer Program: Helping Hands Across Public Lands – Phase Ii: Annual Progress Report, Period Covering July 1, 2008 - June 30, 2009, Margaret N. Rees

Get Outdoors Nevada

  • From July 1, 2008 to June 30, 2009 the Volgistic database has increased the number of records by 20% containing a total 6,226 records at the end of this period.
  • Website activity this year averaged 63,590 hits per month, with an average of 5,290 pages viewed per month.
  • The IVP team presented a summary of their accomplishments to the SNAP board.
  • The team attended 13 community outreach events resulting in 2,501 direct contacts and 394 new mailing list records.
  • How to Succeed with Volunteers training was held for SNAP personnel.
  • The IVP team met with four SNAP teams to develop …


Joint Fire Science Program – Lake Mead National Recreation Area: Revegetating Burned Arid Lands: Identifying Successful Native Species Using Trait And Competition Analysis, Quarterly Progress Report, April 1 — June 30, 2009, Margaret N. Rees Jun 2009

Joint Fire Science Program – Lake Mead National Recreation Area: Revegetating Burned Arid Lands: Identifying Successful Native Species Using Trait And Competition Analysis, Quarterly Progress Report, April 1 — June 30, 2009, Margaret N. Rees

Fire Science

  • Initiated a competitive hierarchy study.
  • Monitored and maintained outplanting at Goodsprings.
  • Completed more seed granivory trials at Goodsprings.
  • Mentored student to completion of undergraduate research project.
  • Monitored and maintained nursery plots.
  • Revising article submitted to Journal of Arid Environments.


Lake Mead National Recreation Area Monitoring And Evaluation Of Sensitive Wildlife: Quarterly Progress Report, Period Ending June 30, 2009, Margaret N. Rees Jun 2009

Lake Mead National Recreation Area Monitoring And Evaluation Of Sensitive Wildlife: Quarterly Progress Report, Period Ending June 30, 2009, Margaret N. Rees

Wildlife Monitoring

Project 1. Relict Leopard Frog Monitoring, Management, and Research

  • All milestones and deliverables associated with the MSHCP project are on schedule
  • Translocation field season has been completed
  • Spring monitoring surveys have been completed
  • Dana Drake, UNLV Research Assistant, has left the project

Project 2. Bald Eagle Winter Monitoring and Evaluation

  • All MSHCP milestones and deliverables are on schedule

Project 3. Peregrine Falcon Monitoring and Evaluation

  • The MSHCP projects are on schedule for all milestones and deliverables
  • Peregrine falcon monitoring of breeding activities are ongoing and are nearing completion
  • Method testing of active survey methodology has been completed
  • Stacy Crowe was …


Natural Life Histories Of Alaska Colias (Lepidoptera: Pieridae), Jack L. Harry Jun 2009

Natural Life Histories Of Alaska Colias (Lepidoptera: Pieridae), Jack L. Harry

The Taxonomic Report of the International Lepidoptera Survey

Eight species of the genus Colias of Alaska were studied during the years of 2005, 2006, and 2007. Natural life histories were determined, immature stages described, measured, and photographed. Scanning Electron Microscope (SEM) pictures of the micropyle of five species are included.


Phylogenetic Analyses Reveal Monophyletic Origin Of The Ergot Alkaloid Gene Dmaw In Fungi, Miao Liu, Daniel G. Panaccione, Christopher L. Schardl Jun 2009

Phylogenetic Analyses Reveal Monophyletic Origin Of The Ergot Alkaloid Gene Dmaw In Fungi, Miao Liu, Daniel G. Panaccione, Christopher L. Schardl

Plant Pathology Faculty Publications

Ergot alkaloids are indole-derived mycotoxins that are important in agriculture and medicine. Ergot alkaloids are produced by a few representatives of two distantly related fungal lineages, the Clavicipitaceae and the Trichocomaceae. Comparison of the ergot alkaloid gene clusters from these two lineages revealed differences in the relative positions and orientations of several genes. The question arose: is ergot alkaloid biosynthetic capability from a common origin? We used a molecular phylogenetic approach to gain insights into the evolution of ergot alkaloid biosynthesis. The 4-γ,γ-dimethylallyltryptophan synthase gene, dmaW, encodes the first step in the pathway. Amino acid sequences deduced …


A New Brevicipitid Species (Brevicipitidae: Callulina) From The Fragmented Forests Of The Taita Hills, Kenya, Simon P. Loader, G. John Measey, Rafael O. De Sá, Patrick K. Malonza Jun 2009

A New Brevicipitid Species (Brevicipitidae: Callulina) From The Fragmented Forests Of The Taita Hills, Kenya, Simon P. Loader, G. John Measey, Rafael O. De Sá, Patrick K. Malonza

Biology Faculty Publications

A new species Callulina dawida is described from the Taita Hills, Kenya. It is distinguished from other members of the genus on the basis of the degree of digital expansion. The species further differs from other members of the genus based on molecular sequence comparisons and on its call. The morphological variation in the new species is described, including a comparison of internal and external characters and sexual dimorphism with other species of Callulina. The conservation status of the species, on the basis of its restricted distribution and land use changes in the area, is considered to be of …


Purple Martin, Progne Subis, In San Luis Obispo County Riparian Habitat: Presence, Persistence, Nesting, Brooding And Reproductive Success, Shannon Eileen Murphy Jun 2009

Purple Martin, Progne Subis, In San Luis Obispo County Riparian Habitat: Presence, Persistence, Nesting, Brooding And Reproductive Success, Shannon Eileen Murphy

Biological Sciences

The State of California, as of 2002, identified the Purple Martin as a bird species of Special Concern (Airola et al., 2003). These migrants were historically found in a unique habitat in Central California; nesting in natural cavities of Western Sycamores within Riparian Habitats. I am proposing that Purple Martins still successfully nest and brood young in this unique habitat in San Luis Obispo County. The primary study site is in Atascadero where Highway 41 meets San Gabriel Road and San Gabriel Road crosses Atascadero creek. The secondary site is Highway 58 in Santa Margarita where the highway crosses the …


Loss Of Shoaling Preference For Familiar Individuals In Captive-Reared Crimson Spotted Rainbowfish Melanotaenia Duboulayi, Erin Kydd, Culum Brown Jun 2009

Loss Of Shoaling Preference For Familiar Individuals In Captive-Reared Crimson Spotted Rainbowfish Melanotaenia Duboulayi, Erin Kydd, Culum Brown

Sentience Collection

Captive-reared rainbowfish Melanotonia duboulayi showed no preference for familiar individuals in an experiment examining shoaling preferences. Fortnightly re-examination of the shoaling preferences of the captive-reared population showed that the lack of preference for familiar individuals did not alter over an 8 week period. The same experiment performed on laboratory-reared offspring raised in isolated groups for 8 months since hatching also showed no preference for shoals consisting of familiar individuals. In contrast, trials performed on a wild population of M. duboulayi found a strong preference for familiar shoalmates, a result that is consistent with previous studies. The lack of shoaling preferences …


The Relationship Between Plasma Steroid Hormone Concentrations And The Reproductive Cycle Of The Northern Pacific Rattlesnake, Crotalus Oreganus, Craig Michael Lind Jun 2009

The Relationship Between Plasma Steroid Hormone Concentrations And The Reproductive Cycle Of The Northern Pacific Rattlesnake, Crotalus Oreganus, Craig Michael Lind

Master's Theses

To gain a better understanding of the role of steroid hormones in vertebrate reproduction, we quantified steroid hormone concentrations in a free ranging population of the Northern Pacific rattlesnake, Crotalus oreganus. Plasma steroid hormone concentrations were quantified for both male and female snakes throughout the active season (Mar-Oct). We measured testosterone (T), 5α-dihydrotestosterone (DHT), and corticosterone (B) concentrations in male and female snakes. 17β-estradiol (E2) and progesterone (P) were measured in females only. We also observed breeding behaviors (e.g. consortship, courtship, and copulation) in the field and measured testis and follicle size in male and female snakes from museum collections. …


Alternative Life Cycle Strategies And Colonization Of Young Anurans By Gorgoderina Attenuata In Nebraska, Matthew G. Bolek, Scott D. Snyder, John J. Janovy Jr. Jun 2009

Alternative Life Cycle Strategies And Colonization Of Young Anurans By Gorgoderina Attenuata In Nebraska, Matthew G. Bolek, Scott D. Snyder, John J. Janovy Jr.

Biology Faculty Publications

Studies on life cycles and epizootiology of North American frog bladder flukes indicate that adult frogs become infected predominantly by ingesting tadpoles or other frogs that serve as second intermediate hosts for gorgoderid metacercariae. Other studies have indicated that newly metamorphosed frogs are rarely infected with these parasites because they are gape-limited predators that cannot feed on large intermediate hosts such as tadpoles and other frogs. We examined the role of potential intermediate hosts in the recruitment of the frog bladder fluke, Gorgoderina attenuata, to metamorphosed northern leopard frogs, Woodhouse’s toads, and bullfrogs from western Nebraska. We completed the …


Modeling And Analysis Of The Spread Of Japanese Encephalitis With Environmental Effects, Ram Naresh, Surabhi Pandey Jun 2009

Modeling And Analysis Of The Spread Of Japanese Encephalitis With Environmental Effects, Ram Naresh, Surabhi Pandey

Applications and Applied Mathematics: An International Journal (AAM)

A nonlinear mathematical model for the spread of Japanese Encephalitis, caused by infected mosquito feeding on susceptible human population incorporating demographic and environmental factors is proposed and analyzed. In the modeling process, it is assumed that the growth rates of reservoir animal population and vector mosquito population are enhanced due to environmental discharges caused by human population related factors. The model is analyzed by stability theory of differential equations and computer simulation. Both the disease-free and the endemic equilibria are found and their stability is investigated. It is found that whenever the disease-free equilibrium is locally asymptotically stable, the endemic …


Occurrence Of Trichosirocalus Horridus (Coleoptera: Curculionidae) On Native Cirsium Altissimum Versus Exotic C. Vulgare In North American Tallgrass Prairie, Masaru Takahashi, Svata M. Louda, Tom E. X. Miller, Charles W. O'Brien Jun 2009

Occurrence Of Trichosirocalus Horridus (Coleoptera: Curculionidae) On Native Cirsium Altissimum Versus Exotic C. Vulgare In North American Tallgrass Prairie, Masaru Takahashi, Svata M. Louda, Tom E. X. Miller, Charles W. O'Brien

Svata M. Louda Publications

Postrelease studies can provide data with which to evaluate expectations based on prerelease tests of biological control insects. In 2004, we observed Trichosirocalus horridus Panzer (Coleoptera: Curculionidae), the rosette weevil introduced into North America against Eurasian thistles, feeding on native tall thistle, Cirsium altissimum L. Spreng., in tallgrass prairie. In this study, we examined the rosette weevil's use of tall thistle, compared with its use of the co-occurring exotic bull thistle, C. vulgare (Savi) Tenore. For both thistle species, we quantified weevil frequency, abundance, and seasonal variation in incidence, using both timed observations at two sites over two growing seasons …