Life Sciences Commons^™

Modeling The Effect Of Post-Dispersal Seed Predation On Tropical Tree Species In Panama, Justin Tirrell

Fall Student Research Symposium 2018

Palm trees provide a unique opportunity to study what conditions optimize the probability that a seed will grow successfully. The seeds of palm trees, endocarps, are large and easy to locate. When they don't grow, predators leave marks on them that tell the story of their fate. The focus of my experiment is to determine how the current distribution pattern of parent palm trees in Panama Palm trees affects the the future distribution of seedlings. I have programmed a versatile model that takes the assumption that bruchid beetles are the sole predators acting on the seeds, and that these fall …

The Nesting Ecology Of Woodpeckers In The Eastern Cascades And Their Interactions With Nest Competitors And Predators, Samuel D. Cowell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Woodpeckers create nesting cavities for other birds and animals in forests. This creates dynamic interactions between both woodpeckers and these other animals. Using video cameras, we documented direct behavioral interactions between nesting woodpeckers and other animals in the Eastern Washington Cascades during the 2015 and 2016 breeding seasons. Additionally, we offered 937 students in a General Biology laboratory course to participate in this original research opportunity and described and the impact the experience had on the participants as well as the researchers.

In 2015, Western Blubebirds took over two active Black-backed Woodpecker nests by physically attacking the woodpeckers. In 2016, …

Occurrence Of Camponotus Pennsylvanicus (Hymenoptera: Formicidae) In Trees Previously Infested With Enaphalodes Rufulus (Coleoptera: Cerambycidae) In The Ozark Mountains Of Arkansas, Robin M. Verble-Pearson, Fred M. Stephen

Robin M. Verble

Black carpenter ants, Camponotus pennsylvanicus (DeGeer), are nearly ubiquitous in North American forests. These ants are documented as predators of red oak borer, Enaphalodes rufulus (Haldeman), a native longhorn beetle that experienced an unprecedented population increase synonymous with an oak decline event in the oak hickory forests of the Ozark Mountains of Arkansas from the late 1990s until 2005. We examined previous red oak borer emergence holes, tree crown conditions, and site aspects in 13 pre-established vegetation monitoring plots and correlated these forest and tree attributes with the presence or absence of black carpenter ants. At each site, all red …

Predators Modify The Temperature Dependence Of Life-History Trade-Offs, Thomas M. Luhring, Janna M. Vavra, Clayton E. Cressler, John Delong

School of Biological Sciences: Faculty Publications

Although life histories are shaped by temperature and predation, their joint influence on the interdependence of life-history traits is poorly understood. Shifts in one life-history trait often necessitate shifts in another—structured in some cases by trade-offs— leading to differing life-history strategies among environments. The offspring size–number trade-off connects three traits whereby a constant reproductive allocation (R) constrains how the number (O) and size (S) of offspring change. Increasing temperature and size-independent predation decrease size at and time to reproduction which can lower R through reduced time for resource accrual or size-constrained fecundity. We investigated how O, S, and R in …

Population Dynamics Of The Threatened Staghorn Coral, Acropora Cervicornis, And The Development Of A Species-Specific Monitoring Protocol, Elizabeth Goergen

HCNSO Student Theses and Dissertations

Historically, Acropora cervicornis was found in high densities on many Caribbean, Florida, and Gulf of Mexico reefs. A disease outbreak in the late 1970s and 80s caused up to 99% loss of A. cervicornis cover at some sites, leaving populations sparsely distributed throughout its range and typically found as isolated colonies. Even though populations are depauperate causing a decrease in sexual reproduction, its fast growth rate and ability to reproduce through asexual fragmentation affords this species the potential for quick recovery and population growth. However, limited to no natural recovery has been documented. Many of these populations are poorly studied …

Competition And Predation: Interactions Between American Eels (Anguilla Rostrata) And Brook Trout (Salvelinus Fontinalis) In Virginia Mountain Streams, Jonathan Studio

Masters Theses, 2010-2019

Competition has played a large role in structuring natural communities, especially with regards to vulnerable organisms. Brook trout and American eel populations have declined in the Mid-Atlantic Region of the United States as a result of anthropogenic development around freshwater ecosystems, and thus, subsequent conservation efforts of both species have included habitat restoration. Conservation efforts have increased the co-occurrence of these predatory fish species that are known to require similar resources. The main objective of this research was to elucidate the potential for competition between brook trout and American eels through analysis of their preferred prey, diet overlap, and supplementary …

Predator-By-Environment Interactions Mediate Bacterial Competition In The Dictyostelium Discoideum Microbiome, R Fredrik Inglis, Odion Asikhia, Erica Ryu, David C. Queller, Joan E. Strassmann

Biology Faculty Publications & Presentations

Interactions between species and their environment play a key role in the evolution of diverse communities, and numerous studies have emphasized that interactions among microbes and among trophic levels play an important role in maintaining microbial diversity and ecosystem functioning. In this study, we investigate how two of these types of interactions, public goods cooperation through the production of iron scavenging siderophores and predation by the social amoeba Dictyostelium discoideum, mediate competition between two strains of Pseudomonas fluorescens that were co-isolated from D. discoideum. We find that although we are able to generally predict the competitive outcomes between …

Changes In Hatchery Subsidies Of Chinook Salmon In The Salish Sea: Implications For Predators, Fisheries, And Conservation, Benjamin Nelson, Eric John Ward, Ole Shelton, Joseph H. Anderson

Salish Sea Ecosystem Conference

Historically, salmon hatcheries were designed to increase fishery production and to recover depleted native populations. As demands of human protein consumption increase and wild populations continue to decline due to anthropogenic impacts like climate change and habitat loss, hatcheries and stocking programs will be called on to provide food security and to supplement threatened populations. Since 1950 over 3.7 billion Chinook salmon have been released into the Salish Sea and its tributaries in Washington State and southern British Columbia. However, relatively little research has been conducted that considers the impact of hatchery subsidies on estuarine and nearshore marine ecosystems in …

Interannual Variation In Early Marine Survival Patterns Of Puget Sound Steelhead Smolts Indicates Shifting Predation Pressures, Barry A. Berejikian, Megan Moore, Steve Jeffries

Salish Sea Ecosystem Conference

Marine survival of steelhead smolts during their two week migration from river mouths to the Strait of Juan de Fuca has been estimated at 20% or less for several populations originating in Puget Sound. Low survival rates likely reduce overall smolt-to-adult return rates and limit recovery of Puget Sound steelhead populations. Harbor seals are generalist predators known to eat juvenile salmon in the Salish Sea. Harbor seals were captured in 2014 (12 seals) and 2016 (16 seals) and outfitted with acoustic telemetry receivers and GPS tags to quantify likely predation events and estimate foraging area overlap with acoustically tagged steelhead …

Foraging Opportunity: A Method Of Monitoring Shorebird Migration And Overwintering Sites In A Changing Environment, James Rourke, Wendell Challenger, Ron Ydenberg

Salish Sea Ecosystem Conference

Roberts Bank within the Fraser River estuary, BC contains important migratory stopover and overwintering habitat for shorebirds such as the western sandpiper (Calidris mauri) and the Pacific dunlin (Calidris alpina pacifica). Shorebirds are especially abundant during northward migration, with single-day counts numbering into the hundreds of thousands of birds. Previous research and ecological theory have demonstrated that site usage by shorebirds is influenced by numerous factors, including prey availability and predation risk. We developed a concept termed “foraging opportunity” that quantifies shorebird food availability (biofilm, meiofauna, and macrofauna) in relation to predation danger from hunting falcons. Foraging opportunity was determined …

African Penguins Follow The Gaze Direction Of Conspecifics, Christian Nawroth, Egle Trincas, Livio Favaro

Christian Nawroth, PhD

Gaze following is widespread among animals. However, the corresponding ultimate functions may vary substantially. Thus, it is important to study previously understudied (or less studied) species to develop a better understanding of the ecological contexts that foster certain cognitive traits. Penguins (Family Spheniscidae), despite their wide interspecies ecological variation, have previously not been considered for cross-species comparisons. Penguin behaviour and communication have been investigated over the last decades, but less is known on how groups are structured, social hierarchies are established, and coordination for hunting and predator avoidance may occur. In this article, we investigated how African penguins (Spheniscus demersus) …

Predator Presence And Size Variation Alters Community Structure Through Multiple Trophic Cascades, Robin Baker, Howard Whiteman Ph.D.

Murray State Theses and Dissertations

Predation plays a crucial role in shaping community structure and can initiate trophic cascades that can alter abundances across adjacent trophic levels. Recent research has suggested that variation among individual predators may have stronger effects on ecological dynamics than previously appreciated. Intraspecific variation within predators could lead to differential levels of top-down control with implications for trophic cascade strength. In this experiment, we manipulated the body size variation of predatory mole salamanders (Ambystoma talpoideum) within experimental mesocosms and monitored a suite of abiotic and biotic response variables. We predicted that predator populations with increased body size variation would …

Comparing The Effects Of Two Tillage Operations On Beneficial Epigeal Arthropod Communities And Their Associated Ecosystem Services In Sugar Beets, Rudolph J. Pretorius, Gary L. Hein, Erin E. Blankenship, Foster F. Purrington, Robert G. Wilson, Jeff D. Bradshaw

Department of Entomology: Faculty Publications

Beneficial arthropods provide important ecosystem services in terms of arthropod pest and weed management, but these services can be adversely affected by farming practices such as tillage. This study investigated the impact of two tillage operations (zone tillage and moldboard plow) on the activity density of several beneficial, epigeal arthropod taxa, and postdispersal weed seed and prey removal in sugar beet agroecosystems. In addition, four omnivorous ground beetle species were selected for a weed-seed choice feeding assay, whereas a single species was selected for a weed-seed age preference assay. Ground beetles were the most commonly collected taxon (via pitfall sampling), …

An Historical Overview And Update Of Wolf-Moose Interactions In Northeastern Minnesota, L. David Mech, John Fieberg, Shannon M. Barber-Meyer

USGS Northern Prairie Wildlife Research Center

Wolf (Canis lupus) and moose (Alces americanus) populations in northeastern Minnesota, USA, have fluctuated for decades and, based on helicopter counts, moose numbers declined to a new low from 2006 to about 2012. Other steep declines were found in 1991 and 1998 during periods when moose counts were done with fixed-wing aircraft; these declines also appeared to be real. Winter wolf numbers, monitored in part of the moose range, had been increasing since about 2002 to the highest population in decades in 2009. However, from 2009 to 2016, wolves decreased precipitously, and the moose- population decline leveled …

Context-Dependent Interactive Effects Of Non-Lethal Predation On Larvae Impact Adult Longevity And Body Composition, Karthikeyan Chandrasegaran, Samyuktha Rao Kandregula, Suhel Quader, Steven A. Juliano

Faculty Publications – Biological Sciences

Predation impacts development, behavior and morphology of prey species thereby shaping their abundances, distribution and community structure. Non-lethal threat of predation, specifically, can have a strong influence on prey lifehistory characteristics. While investigations often focus on the impact of predation threat on prey in isolation, tests of its interactive effects with food availability and resource competition on prey survival and fitness can improve understanding of costs, benefits and trade-offs of anti-predator strategies. This study, involving Aedes aegypti mosquitoes as a model organism, investigates both simple and interactive effects of predation threat during the larval stage on survival, size at and …

Intercanine Width Measurements To Aid Predation Investigations: A Comparison Between Sympatric Native And Non-Native Carnivores In The Mexican Wolf Recovery Area, Tana Verzuh, David L. Bergman, Scott C. Bender, Maggie Dwire, Stewart W. Breck

USDA Wildlife Services: Staff Publications

Mexican wolves (Canis lupus baileyi) share their range with a number of sympatric carnivores, many of which are a concern to livestock producers because they can prey on livestock. Determining which predator species is responsible for killing livestock is important for determining appropriate management actions and for the conservation of Mexican wolves. A variety of information can be used to decipher which carnivore species was responsible for making a kill, and mandibular (upper) and maxillary (lower) intercanine width measurements (i.e., bite mark analysis) can aid this process. No research has been conducted to validate the usefulness of bite …

Evaluating An Alleged Mimic Of The Monarch Butterfly: Neophasia (Lepidoptera: Pieridae) Butterflies Are Palatable To Avian Predators, Dale A. Halbritter, Johnalyn M. Gordon, Kandy L. Keacher, Michael L. Avery, Jaret C. Daniels

USDA Wildlife Services: Staff Publications

Some taxa have adopted the strategy of mimicry to protect themselves from predation. Butterflies are some of the best representatives used to study mimicry, with the monarch butterfly, Danaus plexippus (Lepidoptera: Nymphalidae) a well-known model. We are the first to empirically investigate a proposed mimic of the monarch butterfly: Neophasia terlooii, the Mexican pine white butterfly (Lepidoptera: Pieridae). We used captive birds to assess the palatability of N. terlooii and its sister species, N. menapia, to determine the mimicry category that would best fit this system. The birds readily consumed both species of Neophasia and a palatable control species but …

Life On The Edge: Risk Of Predation Drives Selection Of Habitat And Survival Of Neonates In Endangered Sierra Nevada Bighorn Sheep, Shannon Forshee

Graduate Student Theses, Dissertations, & Professional Papers

Long-term viability of endangered populations requires development of effective management strategies that target the population vital rate with the highest potential to influence population trajectories. When adult survival is high and stable, juvenile recruitment is the vital rate with the greatest potential to improve population trajectories. For my thesis I examined how lactating Sierra Nevada Bighorn sheep (Ovis Canadensis sierra) balance forage and predation risk during the neonatal period. I first identified resource selection strategies employed by lactating females to promote survival of neonates and then determined the primary factors affecting survival of neonates. I found lactating females selected for …

Temporal Variation In Predation Risk May Explain Daily Rhythms Of Foraging Behavior In An Orb-Weaving Spider, J. Colton Watts, Thomas C. Jones, Ashley Herrig, Madeleine Miller, Brigitte Tenhumberg

School of Biological Sciences: Faculty Publications

Daily rhythms occur in numerous physiological and behavioral processes across an immense diversity of taxa, but there remain few cases in which mechanistic links between rhythms of trait expression and organismal fitness have been established. We construct a dynamic optimization model to determine whether risk allocation provides an adaptive explanation for the daily foraging rhythm observed in many species using the orb-weaving spider Cyclosa turbinata as a case study. Our model predicts that female C. turbinata should generally start foraging at lower levels of energy reserves (i.e., should be less bold) during midday when predators are most abundant. We also …