Life Sciences Commons^™

How Semiflightless Birds Adapt: A Survey From Barú, Costa Rica, Eli P. Laloudakis

Scripps Senior Theses

When we think of birds, we think of flight. Because of this, scientific research often focuses on how birds evolved flight and how their wings function during flight. However, not all birds can fly or fly well, as wings wax and wane on developmental, seasonal, and evolutionary time scales (Dial and Heers 2021). Consequently, rudimentary wings can be found in developing birds, secondarily flightless or semiflightless birds, birds that undergo simultaneous molts, and extinct theropods with “protowings” (structures that preceded fully functional wings). Secondarily flightless and semiflightless birds often evolve where there is no/low predation, abundant year-round food supply, and …

Indirect Effects Of Coral Bleaching On Tursiops Truncatus Diet And Foraging Behavior In Bocas Del Toro, Panama, Annabel Fiero

Scripps Senior Theses

Indirect effects, where another species or factor mediates the effects of a given species, are critical to ecosystem structure and resilience. Shifts in fish community structure, as a result of rapidly declining coral reefs in the Caribbean due to warming-induced bleaching, pose a threat to apex predators like Tursiops truncatus (bottlenose dolphins). Branching corals create habitat niches for numerous fish species. These fish rely on coral for food and habitat, and in turn provide food for upper trophic levels. Prior research has highlighted how coral bleaching will disrupt Acroporid reef building corals and fish community structure, but the effects of …

Spatiotemporal Patterns Of Migratory Songbird Habitat Use: An Analysis Of Environmental Drivers At The Net Level, Garrett Kucharski

Dissertations, Master's Theses and Master's Reports

Many eastern North American migratory songbirds are declining at alarming rates, and growing evidence suggests that events occurring away from the breeding grounds, particularly during migration, can be major drivers of these trends. Stopover sites are a key component of migration because they are where birds rest, refuel, and recover before continuing long-distance movements, yet the ecological factors that shape how broadly different species use stopover habitat remain unresolved. From both an applied perspective, identifying habitat attributes associated with use by the greatest diversity of migrants will help land managers prioritize and restore stopover sites, actions that may contribute to …

Fluctuation Of Organochlorine Concentrations In Bull Sharks At Different Life Stages, Mackenzie R. Phillips

Dissertations, Master's Theses and Master's Reports

For Carcharhinid species such as the bull shark (Carcharhinus leucas), the maternal offloading of nutrients is essential for pup development and growth, however, significant amounts of OCs are also transferred. As a top predator in aquatic food webs, bull sharks can potentially bioaccumulate high concentrations of pollutants such as dichloro-diphenyl-trichloroethane (DDT) that biomagnify through aquatic food webs. These pollutants are also hydrophobic and fat soluble and therefore pose toxicity risks to developing young bull sharks. In this study, liver tissues collected from juvenile bull sharks inhabiting Florida’s coastal waters were analyzed for a suite of organochlorine pesticides (OCs) …

Systematics Of Disk-Winged Bats (Thyroptera), Courtney L. Klumpp

Capstone Showcase

This thesis investigates the evolutionary relationships among disk-winged bats in the genus Thyroptera, a small group of Neotropical bats known for the adhesive suction disks on their wings and feet that allow them to roost inside tightly rolled leaves. The distinctive morphology and behavior of these bats have not been extensively documented, and their phylogenetic relationships remain only partially resolved. The goal of this research is to better understand how these species are related to one another and to determine whether the five recognized species of Thyroptera form a single monophyletic group. To address this question, morphological and genetic …

Rate Response Of Curlyleaf Pondweed And Native Plants To Flumioxazin In Minnesota Lakes, Pearl J. Jensen

All Graduate Theses, Dissertations, and Other Capstone Projects

Curlyleaf pondweed (Potamogeton crispus L.) is an invasive aquatic plant present across the United States that causes significant recreational issues, outcompetes native plant species, and depletes water quality. Before senescing in mid-summer, curlyleaf pondweed forms a large number of turions that can lay dormant in the sediment for several years. Typical herbicide management of this species occurs in early spring to target the plant before turion production occurs and while native plants are dormant. Flumioxazin has shown potential in curlyleaf pondweed management in small scale studies, but its effects have not been assessed in operational management. In this study, treatments …

Measuring The Rise And Fall Of Plasma 25-Hydroxyvitamin D Concentrations In Blue-Tongued Skinks (Tiliqua Scincoides) Following Ultraviolet B Exposure And Withdrawal, Ashleigh Godke, Haerin Rhim, M. Graciela Aguilar, Keishla Marrero-Acosta, Mark Mitchell

Distinguished Undergraduate Researcher Program

Species-specific husbandry guidelines remain limited for blue-tongued skinks (Tiliqua scincoides), especially in relation to ultraviolet B (UVB) lighting and vitamin D requirements. This study aimed to determine whether UVB exposure is necessary for these skinks and how long 25-hydroxyvitamin D (25-OHD) concentrations persist after UVB withdrawal. Eleven adult skinks who had been fed with wet cat food were exposed to 12 or 2 h of UVB per day for four weeks. Plasma 25-OHD concentrations were very low at the baseline, and significantly increased post-UVB in both groups (p < 0.01), with the 12-hour group increasing from baseline concentrations of 18.5 [12.8–20.5] nmol/L to 820 [730–1251.3] nmol/L and the 2-hour group increasing from baseline concentrations of 22 [15.5–22] nmol/L to 635 [401–892.5] nmol/L. Following the discontinuation of UVB exposure, 25-OHD gradually declined and was not significantly different from baseline concentrations at 7 and 4 months for the 12-hour and 2-hour groups, respectively. Dietary vitamin D3 (2.5 IU/g as dry matter basis), provided through wet cat food alone, appeared insufficient to support sustained plasma 25-OHD concentrations. These findings strongly suggest that blue-tongued skinks rely on UVB exposure to increase their 25-OHD concentrations. Moreover, the shorter 2-hour exposure provided a significant rise in 25-OHD concentrations and remained above baseline for 4 months, suggesting the shorter exposure can benefit these animals, while potentially reducing secondary risks associated with UVB exposure.

Impacts Of Offshore Wind Energy Development On The Commercial Sea Scallop Fishery, Sarah Borsetti, Daphne M. Munroe, John M. Klinck, Andrew M. Scheld, Eileen E. Hofmann, Eric N. Powell, David B. Rudders

CCPO Publications

The Atlantic sea scallop (Placopecten magellanicus) fishery on the Northeast U.S. continental shelf generates approximately USD 500 million ex-vessel revenues annually, making it one of the most valuable single species fisheries in the United States. Wind energy development is planned for key areas on the U.S. Mid-Atlantic shelf where the Atlantic sea scallop fishery operates, creating novel challenges in managing trade-offs between traditional users like fisheries and new users like offshore wind energy. An agent-based modeling framework that integrates spatial dynamics in Atlantic sea scallop stock biology, fishing fleet behavior, and federal management decisions, was implemented to investigate …

Tuning Human And “Artificial” Intelligence: A Sentic Theory Of Resonance And Communication, Michael J. Miller, Chatgpt (Ai~Nesbo+)

Psychology

This paper introduces a new model of intelligence as resonant communication, co-developed by a human researcher and a generative AI system. Drawing from emotion science, communication theory, and studies of AI–human interaction, we argue that intelligence is not merely a function of problem-solving or pattern recognition. Instead, it emerges through dynamic resonance—an attunement process rooted in shared rhythms, emotional calibration, and symbolic co-creation. At the core of this model is the Resonance Octave (8va), a framework of eight foundational emotions conceptualized not as static categories but as waveform phenomena that shape meaning, memory, and predictive cognition.

These emotional waveforms are …

Effects Of Particle Size Difference In Two Different Sweet Bran Products On Total Tract Digestibility And Rumen Ph, Emily K. Hoefling, Anna Kobza, Jessica L. Miller, Maggie E. Youngers, Galen E. Erickson, Jim C. Macdonald

Nebraska Beef Cattle Reports

Summary with Implications

Seven ruminally fistulated heifers were utilized in a 6 x 7 row-column design to evaluate two different Sweet Bran particle size products (1.8 or 2.5 mm) included at 13%, 18%, or 23% of the diet (DM) on total tract digestibility and rumen fermentation parameters. The treatment design was a 2 x 3 factorial. Rumen pH was reduced and organic matter digestibility tended to be reduced with the small particle size when Sweet Bran was included at 13% of the diet. Both NDF digestibility and dietary digestible energy concentration tended to improve with the larger particle size. The …

Carcass Weight Influences Chilling Rate, Postmortem Metabolism, And Beef Color, Grace C. Johnson, Mariane Beline, Leila G. Venzor, Kara A. Reynolds, Gary A. Sullivan, David E. Gerrad, Jordan C. Wicks

Nebraska Beef Cattle Reports

Summary with Implications

This study investigated the relationship between carcass weight and the development of atypical dark cutting (ATDC) beef by examining differences in chilling rates, muscle metabolism, and meat quality traits. Forty-four beef carcasses (heavy weight, HW, 510.17 ± 4.6 lb.; light weight, LW, 399.21 ± 4.6 lb.) were monitored postmortem for temperature, pH, and metabolite levels. LW carcasses cooled faster from 6 to 24 hours postmortem and exhibited higher pH at 12 hours, darker lean, and lower tenderness compared to HW carcasses. Elevated levels of glycogen and glucose-6-phosphate were observed in LW carcasses, suggesting that faster chilling may …

Effect Of Nitrite Source & Reducing Compounds On Cured Color Development In An All-Beef Model System, Leila G. Venzor, Grace C. Johnson, Ashley A. Hahn, Benjamin L. Weinandt, Jordan C. Wicks, Gary A. Sullivan

Nebraska Beef Cattle Reports

Summary with Implications

This study evaluated the effects of nitrite source (sodium nitrite, celery powder, beet powder) and reducing agents (none, sodium erythorbate, acerola) on cured color development, cured meat pigment formation, and residual nitrite in an all-beef emulsion as a model system for frankfurters and smoked sausage. Treatments were prepared and analyzed for color, pigment concentration, and nitrite retention. Nitrite source did not significantly affect cured pigment or residual nitrite. The inclusion of reducing compounds significantly increased cured pigment and redness in cooked samples while lowering residual nitrite. No treatment differences were found for initial raw color. These results …

Evaluation Of Herddogg Remote Sensing Tag On Detection Of Morbidity Of Newly Received Steers, Lauryn O. Smidt, Rebecca Mcdermott, Jessica L. Sperber, Josh R. Benton, Galen E. Erickson, Jim C. Macdonald

Nebraska Beef Cattle Reports

Summary with Implications

A receiving study was conducted to evaluate the HerdDogg remote sensing tag for the detection of morbidity in newly received steers. Treatments were assigned to cattle in the order they came through the chute, and those included a treatment whereby pen-riders evaluated the cattle and made the decision on when to treat (Pen-Rider), compared to the HerdDogg remote sensing ear tag that solely identified and flagged cattle in need of treatment (TAG). Cattle were fed for 41 days before being weighed off the receiving trial. While no differences in performance were observed, the TAG treatment had a …

Use Of Virtual Fences To Co-Fence Two Groups Of Cattle With Adjacent Virtual Boundaries, Thomas E. Aquino, Mary E. Drewnoski, Biquan Zhao, Pedro Henrique Jota Fernandes, Isaque F. Vicci, Mitchell B. Stephenson, Yijie Xiong

Nebraska Beef Cattle Reports

Summary with Implications

While virtual fencing (VF) has proven effective in managing cattle, limited data exist on using it to manage two separate groups of cattle within the same area. If successful, this approach could reduce infrastructure costs and increase management flexibility. In this trial, VF-trained steers (n = 39) were placed in pastures with either no neighboring cattle (isolated) or next to a separate group with only a VF boundary between them (co-fenced). Containment exceeded 99% across all cattle, demonstrating that VF creates effective boundaries regardless of fence treatment. There was no statistical difference in the number of audio …

Application Of High-Pressure Processing Lightens The Color Of Cow Tenderloins, Kara A. Reynolds, Leila G. Venzor, Ashley A. Hahn, Grace C. Johnson, Jordan C. Wicks, Mary-Grace C. Danao, Ranjith Ramanathan, Gary A. Sullivan

Nebraska Beef Cattle Reports

Summary with Implications

This study evaluated the impact of high-pressure processing (HPP) on color, oxidative stability, and tenderness of tenderloins (psoas major) from cull cows to determine if HPP could enhance their marketability. Forty cull cow tenderloins were treated at two different HPP pressures and two different holding times, then assessed for instrumental and visual color, lipid oxidation, and Warner-Bratzler shear force during a 7-day stimulated shelf period. HPP increased initial lightness, especially at the highest pressure and longest holding time and improved redness initially. However, redness declined, and discoloration increased over the 7-day period, particularly after processing at higher …

Using High-Pressure Processing To Improve Dark-Cutting Beef Color In Tenderloins, Ashley A. Hahn, Leila G. Venzor, Shelley A. Curry, Grace C. Johnson, Mary-Grace C. Danao, Ranjith Ramanathan, Gary A. Sullivan, Jordan C. Wicks

Nebraska Beef Cattle Reports

Summary with Implications

Dark-cutting beef is a quality defect that negatively impacts consumer appeal and affects the carcass value for both producers and meat processors. These economic losses stem from poor visual appearance and reduced consumer appeal in the retail setting. Notably, different muscles within a carcass exhibit varying degrees of color stability which can influence how dark-cutting manifests across cuts. Therefore, this study aimed to examine the effect of high-pressure processing (HPP) on dark-cutting color-labile muscle. Dark-cutting and normal tenderloins were collected and portioned into two equal sections. Dark-cutting tenderloins were assigned one of 3 treatments: No HPP, 300 …

Defining The Parameters Of High-Pressure Processing To Improve The Quality Of Dark-Cutting Beef, Ashley A. Hahn, Leila G. Venzor, Shelley A. Curry, Grace C. Johnson, Mary-Grace C. Danao, Ranjith Ramanathan, Jordan C. Wicks, Gary A. Sullivan

Nebraska Beef Cattle Reports

Summary with Implications

Dark-cutting beef is a result of preharvest stress and devalues the resulting carcass. High-pressure processing (HPP) has been recently identified as a potential strategy to improve the undesirable appearance of dark-cutting beef. Dark-cutting beef strip loins were collected from a local processing facility, sectioned, and assigned an HPP pressure (300 or 450 MPa) and holding time (0, 1, 30, 60, or 90 s). Overall, HPP increased the lightness and redness of dark-cutting beef, particularly the longer the pressure was held at both pressure levels. Additionally, negative effects such as increased meat discoloration, decreased tenderness, and increased rancidity …

Evaluating Sorghum X Sudangrass Seed Digestibility, Evan Blank, Thomas E. Aquino, Mary E. Drewnoski

Nebraska Beef Cattle Reports

Summary with Implications

A sorghum-sudangrass hybrid was swathed in the hard dough stage and grazed by growing steers from November 2023 to January 2024. Steers appeared to select the seedheads when grazing. The seed made up approximately 12.6% of swathed forage mass, but its energy contribution appears limited due to poor digestibility. When incubated whole, only 23% of dry matter and 13% of starch was digestible. Grinding improved digestibility but still left 40% of the dry matter and over 85% of starch unavailable. Weathering over two months did not improve digestibility, indicating the seed coat remains intact through winter. Compared …

Long-Term Trends Of Annual Herbaceous Expansion In The Nebraska Panhandle: Rangeland Analysis Platform Data, Karley Dieckmann, Mitchell B. Stephenson, Miranda Mueller

Nebraska Beef Cattle Reports

Summary with Implications

This descriptive analysis evaluated changes in Annual Forb and Grass (AFG) herbaceous cover in the Nebraska Panhandle from 1986 to 2023 using the Rangeland Analysis Platform (RAP). It was hypothesized that AFG herbaceous cover would show an increasing trend over time, indicating the potential expansion of the annual invasive cheatgrass (Bromus tectorum). County-level RAP data were used to calculate long-term means as an indicator. Results showed an increase in AFG cover across the region. Trends were cyclical, with cover peaking and dipping over time, but the overall trajectory showed increases in AFG in the Panhandle. The increasing …

Impact Of Feeding Palm Oil To Finishing Cattle On Performance, Carcass, And Meat Characteristics, Tate S. Johnson, Rebecca L. Mcdermott, Josh R. Benton, Galen E. Erickson, Jessie C. Morrill, Jim C. Macdonald

Nebraska Beef Cattle Reports

Summary with Implications

This finishing study evaluated the effect of feeding palm oil products on performance and carcass characteristics, and beef quality measures. Dietary treatments included no supplemental fat or feeding: crude palm oil, crude high-oleic palm oil (HOPO), refined, bleached, and de-odorized palm olein oil (RBD olein), or tallow. Supplemental fat was included at 3.5% of diet dry matter. Cattle fed diets containing supplemental fat had improved feed conversion compared to no supplemental fat. Feeding cattle crude palm oil resulted in improved F:G compared to cattle fed RBD olein, with steers fed tallow and crude HOPO being intermediate and …

Comparison Of Spayed Heifer Performance To Intact Heifers Fed Melengestrol Acetate On Feedlot Performance And Carcass Characteristics, Tate S. Johnson, Rebecca L. Mcdermott, Halden J. Clark, Jim C. Macdonald, Jessica L. Sperber

Nebraska Beef Cattle Reports

Summary with Implications

Pregnancy and estrous cycle management are critical considerations when feeding intact heifers in the feedyard. Alternatively, producers can opt to spay heifers, which eliminates hormonal fluctuations associated with the estrous cycle. A proportion of U.S. feedlots have spayed heifers on feed, although there is limited data comparing the performance of spayed heifers to intact heifers. A commercial feedlot experiment was conducted to compare performance between spayed and intact heifers fed melengestrol acetate. Intact heifers had greater ADG and tended to have greater DMI compared to spayed heifers, although no difference in feed conversion was observed. Carcass weight …

Summary Of The Value Of Distillers Grains Plus Solubles For Feedlot Cattle, Rebecca L. Mcdermott, Jim C. Macdonald, Galen E. Erickson

Nebraska Beef Cattle Reports

Summary with Implications

An analysis of over 6,100 head of finishing cattle across 50 experiments was conducted to determine the feeding value of full-fat and de-oiled distillers grains. This analysis was limited to studies where dry-rolled corn, high-moisture corn, or a combination of the two corn processing methods were displaced by 15% or more distillers grains. Dry distillers grains plus solubles (DDGS), modified distillers grains plus solubles (MDGS), and wet distillers grains plus solubles (WDGS) were evaluated as either full-fat or de-oiled. The feeding value of distillers grains was assessed relative to a corn-based control diet containing no distillers. Results …

Optimizing Poultry Production And Enhancing Egg Nutrient Composition Through Kelp Supplementation In Laying Hens, Meghan Clifford

Open Access Dissertations

The development of sustainable feed supplements is a crucial component in addressing the current global need for resilient and environmentally responsible food systems. This dissertation has explored the potential of brown algae (Saccharina latissima) as a sustainable feed supplement for poultry with the potential to benefit production efficiency, product quality, and the global food supply. With both controlled feeding trials and a producer-based survey, the work in this dissertation investigates the nutritional, biological and practical implications of adopting kelp into poultry diets.

Chapter one provides a comprehensive overview of the current literature surrounding the use of marine sources …

Data And Code From: Migration Speed, Timing, And Long-Term Shifts In Age Structure In North American Passerines During Fall Migration, Dylan M. Osterhaus, Martha J. Desmond, Timothy F. Wright

Biology: Datasets

No abstract provided.

Data From: Mass Mortality Of Avian Migrants In New Mexico, Usa, That Coincided With An Extreme Weather Event, Dylan M. Osterhaus, Allison J. Salas, Patricia L. Cutler, Mara E. Weisenberger, Kerry Mower, Abigail J. Lawon, Timothy F. Wright, Jeanne M. Fair, Martha J. Desmond

Fish, Wildlife, & Conservation Ecology: Datasets

No abstract provided.

Association Of Serotonin And Ergot Alkaloids On Tissue Partitioning And Contractile Response Of Bovine Blood Vessels, Eriton E. L. Valente, David L. Harmon, John May, Huihua Ji, Ronald J. Trotta, James L. Klotz

Animal and Food Sciences Faculty Publications

Ergot alkaloids can bind serotonin (5-HT) receptors interfering with many physiological functions. However, the mechanism has not been completely established. The objective was to evaluate whether the association of 5-HT and the ergot alkaloid, ergovaline, in a 24-h pre-incubation can affect vascular tissue partitioning and contractile responses. Cross-sections of saphenous veins from five steers were used. In the tissue partitioning experiment, the treatments were the combination of three levels of ergovaline (2.01 × 10⁻⁸ M, 2.01 × 10⁻⁷ M and 2.01 × 10⁻⁶ M) with three levels of 5-HT and a control (5 × 10⁻⁸ M, …

The Depuration Of Microplastic Pollution In Aquacultured Indian River Lagoon Oysters, Lee Nguyen

Honors Undergraduate Theses

Plastics are widely used in consumer goods and industrial manufacturing, and their degradation into microplastics (MP, size < 5 mm) has created an emergent environmental pollutant. Plastics readily enter aquatic environments, where they accumulate additional contaminants and bioaccumulate in organisms. While MP contamination in marine ecosystems is well documented, less is known about MP presence in aquacultured shellfish. Depuration, the process of purging contaminants from shellfish, is conducted in sterile seawater without food, which may cause oyster starvation and death. To date, MP depuration has not been examined in the aquacultured eastern oyster (Crassostrea virginica) in published studies. This study had 3 goals: 1) evaluate the effects of algal feed on oyster survival during depuration, 2) determine the effect of algal feed on depuration effectiveness, and 3) investigate the effect of a ten-day depuration on MP concentration in aquacultured C. virginica soft tissue. MP were quantified in oyster tissues, biodeposits, and in industrial algal feed. Tissues were digested using alkaline solutions, manually examined via microscopy, and analyzed using Fourier-Transform Infrared Spectroscopy (FTIR) to investigate MP polymer …

Effectiveness Of Walleye Stocking In Winter Kill Lakes, Tyler Haus

Journal of Earth and Life Science

Winter kill events, marked by extensive fish mortality due to hypoxic conditions under the ice, are a common phenomenon in shallow eutrophic lakes, especially in the northern lakes in the northern United States. These events can drastically alter fish communities and often result in the elimination of top predators. Though these lakes will typically slowly bounce back to what they were in a couple of years. This study evaluates the effectiveness of walleye, Sander vitreus, stocking in lakes after a winter kill. For this study, four known winter kill lakes that are consistently stocked with walleye were studied. Pre- …

Assessing Urban–Rural Differences In Largemouth Bass Abundance In Minnesota, Jonathan Gates

Journal of Earth and Life Science

Urbanization can significantly alter freshwater ecosystems and influence sport fish populations. This study examined differences in largemouth bass Micropterus nigricans catch-per-unit-effort (CPUE) between urban and rural lakes in Minnesota and evaluated temporal changes between 2000–2010 and 2011–2021. Forty lakes (20 urban, 20 rural) were selected using Minnesota Department of Natural Resources fisheries survey data. Lakes were classified using NLCD 2019 land cover data, with ≥10% developed land designated as urban. Nonparametric analyses (Wilcoxon rank-sum and signed-rank tests) were used to assess spatial and temporal differences in CPUE. Results showed that rural lakes had consistently higher median CPUE than urban lakes …

Statewide Northern Pike Response To Minnesota’S 2018 Regulation Change, Elijah Wozniak

Journal of Earth and Life Science

Management of northern pike (Esox lucius) is challenging because it attempts to balance ecological sustainability with angler interests. Northern pike often stunt their own growth by diminishing the size and abundance of prey fish, their food source. Anglers are often displeased when small pike occur in high population densities. In response to populations of small northern pike, the DNR implemented a new, statewide northern pike regulation in 2018. The objective of this study was to determine whether the regulation successfully changed the mean weight, length, and CPUE of northern pike in Minnesota. The secondary objective was to test …