Life Sciences Commons^™

Analyzing Phototaxis And Related Visual Behaviors Among Diverse Species Of Drosophila, Madeline M. Hill

Honors Theses

Phototaxis and related visual behaviors can vary between species, and thus members of the genus Drosophila make an excellent study system to examine the evolution of vision. While some existing research points to these phototactic behaviors arising due to mating requirements or due to their species-specific ecology or environmental factors, there exists a lack of understanding as to why striking behavioral differences can exist between closely related species, or between members belonging to the same genus. The present research seeks to uncover the specifics regarding these discrepancies in visual evolution and aims to provide a foundation of knowledge about visual …

Cats Of Unl: An Investigation Into The Human-Feral Cat Relationships On A University Campus In Nebraska, Jacey Skoda

Honors Theses

At the University of Nebraska-Lincoln (UNL), there exists a population of feral cats that is monitored and cared for by a group known as Husker Cats. As the cats wander the sidewalks and gardens of the university, they may appear non-threatening and pleasant to have around. However, a feral cat presence could have detrimental impacts on the surrounding ecosystem, property, and community. The first component of this project, a survey of individuals on UNL campus, ultimately seeks to understand what those in the UNL community know about the feral cats, how they feel about the feral cats, and how they …

Cell Volume As A Determinant Of Virus-Mediated Population Growth In Ciliates, Jace Miller, John Paul Delong Phd

Honors Theses

Many protists and other small aquatic organisms consume virus particles, a behavior known as virovory. Some species of protists, such as the ciliate Halteria grandinella, can grow and divide using viruses as their sole food source. Other ciliate species have previously been shown to consume large quantities of viral particles, but it is unclear if they are able to support population growth with viruses alone. Because large ciliates have a higher energy demand, we hypothesize that they will be unable to support population growth on a virus-only diet. We fed nine ciliate species a diet of chloroviruses and found …

Utilizing Markov Chains To Estimate Allele Progression Through Generations, Ronit Gandhi

Honors Theses

All populations display patterns in allele frequencies over time. Some alleles cease to exist, while some grow to become the norm. These frequencies can shift or stay constant based on the conditions the population lives in. If in Hardy-Weinberg equilibrium, the allele frequencies stay constant. Most populations, however, have bias from environmental factors, sexual preferences, other organisms, etc. We propose a stochastic Markov chain model to study allele progression across generations. In such a model, the allele frequencies in the next generation depend only on the frequencies in the current one.

We use this model to track a recessive allele …

Can Gdp Be Predictive Of Fertility Rates In Sweden?, Hannah Coleman

Honors Theses

Fertility rates in a country vary and can be influenced by numerous different aspects of an individual’s life and the society in which they live. One aspect that may influence fertility rates at the national level is the gross domestic product (GDP). GDP is an indicator of a country’s economic productivity. Because fertility is linked to both economic development and individual resources, GDP may be a useful indicator of fertility rates. If so, knowing or predicting GDP could be used to project the fertility rates of a population years into the future. To determine if a reasonable connection between GDP …

Spatiotemporal Interactions Between Deer And Cattle, Sydney Brewer

Honors Theses

Mule deer, white-tailed deer, and cattle are sympatric on the landscape throughout many portions of Nebraska and encounter each other in time and space. By considering variation in daily activity patterns and non-random patterns in the timing of passage through specific locations, we can better understand whether animals may be avoiding each other temporally when sharing space. I investigated temporal activity patterns and avoidance/attraction ratios to investigate if deer altered their activity patterns in the presence of cattle and if they exhibited avoidance at a study site near McCook, Nebraska, USA. We collected data from 19 game cameras that were …

Anthropogenic Change On The Distribution Of Marine Megafauna And Their Prey, Baylie Fadool

Honors Theses

Anthropogenic change is impacting the distribution and survival of marine megafauna and their prey. Humans are changing every aspect of the marine environment, with effects reaching as large as changing the composition of marine environments to directly overexploiting species through the fishing industry. The role that marine megafauna play in balancing ecosystems, including as top apex predators, leads to detrimental results in the absences and population declines of these species. Migrations and declines due to threats on marine apex predator species will alter their environments by causing mesopredator release and changes in community structure, which is often associated with reduced …

Diatom Morphology In Light Of A Changing Climate: A Focus On Aulacoseira Crenulata, Brighid Welchans

Honors Theses

Fossilized diatoms are arguably the most vital proxy record utilized in paleolimnology. Diatoms are unicellular microalgae that are the basis of countless food webs, are invaluable bioindicators, and generate nearly a quarter of global net primary productivity. Diatoms are affected by a variety of environmental factors but there is relatively little research on how environmental conditions impact diatom valve morphology, and in particular whether there is a correlation between incoming light and diatom pore morphology. This report focuses on the Amazon lowland lake Garzacocha, and analyzes the relationship between light levels and the corresponding size of Aulacoseira crenulata pores. We …

An Analysis Of Social Dominance In The Feeding Of Ex Situ Humboldt Penguins (Spheniscus Humboldti), Robert Gabel

Honors Theses

In the field of ecology, complex social structures, including dominance hierarchies, have been demonstrated in a variety of fauna, including bird species. While wild Humboldt Penguins (Spheniscus humboldti) do not exhibit a feeding hierarchy, captive penguins are under very different conditions. Humboldt penguins feed on schooling fish in the wild, but in captivity are hand fed from a zookeeper. I investigated whether there is a nonrandom pattern of dominance in the feeding order of the penguins at the Lincoln Children’s Zoo, in Lincoln, NE, USA. Using a camera and tripod, with assistance from four of the zookeepers, I …

Cercarial Parasitism Of Freshwater Snails In Sandhills Ponds Versus Streams, Caroline Emily Spethman

Honors Theses

Parasite prevalence was calculated for all aquatic snails collected from four freshwater localities in Western Nebraska from Summer 2016 to 2019: Dunwoody Pond, Haythorn Ranch, Neven’s Restoration, and Breen’s Flyaway. With data of increasing trematode cercarial infection specifically at Dunwoody Pond, this community was further studied. In Summer 2019, a total of 217 freshwater snails representing species of Physa sp., Stagnicola elodes (Say,1821), and Helisoma anceps (Menke,1830) were collected from Dunwoody Pond and Dunwoody stream, near Ogallala, Nebraska. Eighty-one snails were collected from Dunwoody Pond, 76 snails were collected 31 meters upstream, and 60 snails were collected 61 meters upstream …

Demographics Of A Painted Turtle (Chrysemys Picta) Population Responding To Drought In The Nebraska Sandhills, Allyson Beard

Honors Theses

A large portion of herpetofauna species are declining as a result of anthropogenic influences such as habitat destruction and climate change, and turtles are no exception. Studying demographics of turtle populations in a wide variety of settings could help establish a baseline for future species management because demographics such as survival and movement are essential to understanding the ecology of a species. We conducted a long-term mark-recapture study on painted turtles (Chrysemys picta) in a permanent pond in the Nebraska Sandhills to exam population size, survival, and movement of an aquatic turtle as drought conditions changed in a …

Using Unmanned Aerial Vehicle Technology To Enhance Conservation Biology Research, Ann Briggs

Honors Theses

This study examined the most effective ways to utilize unmanned aerial vehicles (UAV) for wildlife conservation. More specifically, a UAV platform was created that can perform multiple data collection tasks by utilizing interchangeable modules. The prototype produced in this study has the capability to perform many tasks through the use of interchangeable modules. These tasks include, but are not limited to aerial surveys and collection of biological samples. This innovative technology will provide invaluable assistance to conservation efforts by reducing research and subject injury or death while maximizing efficiency. The modular design of the prototype was developed for retail to …

Olfactory Learning Capabilities Of Paraphrynus Laevifrons, John Perez

Honors Theses

Amblypygids, a species of nocturnal arachnids from the tropics and subtropics are incredibly intelligent and are able to not only navigate through difficult tropical terrain but also, it is believed, possess olfactory learning capabilities that aid in navigation and recollection of environments. It is hypothesized that through sensitive olfactory receptors on their antenniform legs and highly developed mushroom bodies, Amblypygi can not only learn smells but also learn to associate smells with certain stimuli such as a crevice to take refuge in. To test this hypothesis, Paraphrynus laevifrons, a species of amplypygid was subjected to four different learning treatment groups …

One Signal, Two Behaviors: Odor Discrimination In Unmated Versus Mated Female Green Bottle Flies, Lucilia Sericata, George Iannantuono

Honors Theses

The green bottle fly, Lucilia sericata, is of critical importance in the field of forensic entomology since it is one of the first insects to arrive at a freshly deceased carcass. These flies use a highly tuned and selective olfactory system to identify and locate the carcass; response to the decomposition odor usually occurs within minutes. Male flies use the carcass for a small protein meal and for locating females while females use the carcass for feeding (unmated) and egg-laying (mated). This divergence in behavior to a common odor cue is the subject of this thesis proposal: do unmated …

Biodiversity, Ecosystem Function And The Pollination Ecology Of Urban Gardens In Dayton, Ohio, Angela Nicole Giaquinto

Honors Theses

Urban agriculture is an ancient concept that is gaining momentum in the United States in connection with urban renewal projects and efforts to mediate urban food deserts. These agriculture efforts represent a potential habitat for pollinator communities within the urban hardscape. Pollinator communities are threatened by urban landscape transformation, and bee species, in particular, are in a state of global decline due to various stressors. Urban agriculture has the potential to sustain both human and ecological communities, and the pollinators that visit gardens may provide pollination to plant species in the surrounding area. We investigated the influence of urban land …