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Full-Text Articles in Life Sciences

Metabolic Scaling Of Aquatic Macroinvertebrates, Jacob Woelber Apr 2024

Metabolic Scaling Of Aquatic Macroinvertebrates, Jacob Woelber

Honors Thesis

The common assumption in regard to metabolic rate scaling with body size is the 3/4 law, which predicts a scaling exponent of 0.75 between log metabolic rate and log body size. Supporting evidence exists for this theory on a large, general scale. However, factors such as temperature, predation, and environment can cause the scaling exponent to deviate from 0.75. This paper takes a closer look at the effects of temperature and predation on metabolic rates via oxygen consumption in freshwater macroinvertebrate populations. To do this, 24 tanks were filled with water to allow natural populations of macroinvertebrates (predominantly Chironomidae) to …


Foraging Rates From Metabarcoding: Predators Have Reduced Functional Responses In Wild, Diverse Prey Communities, Stella F. Uiterwaal, John Delong Feb 2024

Foraging Rates From Metabarcoding: Predators Have Reduced Functional Responses In Wild, Diverse Prey Communities, Stella F. Uiterwaal, John Delong

School of Biological Sciences: Faculty Publications

Functional responses describe foraging rates across prey densities and underlie many fundamental ecological processes. Most functional response knowledge comes from simplified lab experiments, but we do not know whether these experiments accurately represent foraging in nature. In addition, the difficulty of conducting multispecies functional response experiments means that it is unclear whether interaction strengths are weakened in the presence of multiple prey types. We developed a novel method to estimate wild predators' foraging rates from metabarcoding data and use this method to present functional responses for wild wolf spiders foraging on 27 prey families. These field functional responses were considerably …


Sex And Stress Modulate Pupal Defense Response In Tobacco Hornworm, Sukhman Singh, Sakshi Watts, Ishveen Kaur, Isabella Rodriguez, Jessica Ayala, Dariela Rodriguez, Elian Martin, Rupesh R. Kariyat Oct 2023

Sex And Stress Modulate Pupal Defense Response In Tobacco Hornworm, Sukhman Singh, Sakshi Watts, Ishveen Kaur, Isabella Rodriguez, Jessica Ayala, Dariela Rodriguez, Elian Martin, Rupesh R. Kariyat

Biology Faculty Publications and Presentations

In insects, larval and adult defenses against predators have been well studied. However, pupal (also known as resting stage) defenses have been overlooked and not examined thoroughly. Although some pupa possess antipredator strategies such as hairs, spines, cryptic coloration, and exudation of chemicals, few studies have tested these responses and the factors affecting them. Here, we investigated the behavioral responses in tobacco hornworm Manduca sexta that pupates in soil by introducing an external stimulus using vibrations from an electric toothbrush to mimic predation. We observed that M. sexta made violent wriggling (twitching), followed by pulsating movements in response to the …


Dine And Dash: Changing Harbor Seal Numbers And Habitat Use At The Developing Bellingham Waterfront, Holland Conwell Apr 2023

Dine And Dash: Changing Harbor Seal Numbers And Habitat Use At The Developing Bellingham Waterfront, Holland Conwell

WWU Honors College Senior Projects

The lack of recovery of some Pacific salmon stocks (Oncorhynchus spp.) in the Pacific Northwest has been blamed in part on predation by pinnipeds, particularly the harbor seal (Phoca vitulina). A proposed non-lethal method aimed at managing seal predation on salmon is the removal of artificial haul-out sites. However, the effectiveness of this non-lethal management method has not been examined. To address this knowledge gap, I analyzed harbor seal numbers and habitat use at the developing downtown Waterfront in Bellingham, WA, USA. I examined harbor seal numbers from 2007-2023 throughout multiple log boom removal events at two known harbor seal …


I Ain't Afraid Of No Crab: Intertidal Gastropod Littorina Littorea Behavioral Response To Predation Risk By Carcinus Maenas, Isabelle Erin Smy Apr 2023

I Ain't Afraid Of No Crab: Intertidal Gastropod Littorina Littorea Behavioral Response To Predation Risk By Carcinus Maenas, Isabelle Erin Smy

Honors College

Littorina littorea is an intertidal, invasive gastropod species common in the Gulf of Maine. In this paper, I studied the avoidance and risk-reducing behavioral responses of L. littorea to predation risk by invasive crustacean species Carcinus maenas. Avoidance and risk-reducing behavior in this study are defined by the tendency to move towards the edge and out of a simulated tide pool and the tendency to reduce feeding. The goal of this study was to determine whether the exposure to chemical cues of predators resulted in an increase in avoidance behavior, risk-reducing behavior, and a reduction in the time before the …


Revisiting Plant Defense-Fitness Trade-Off Hypotheses Using Solanum As A Model Genus, Sakshi Watts, Satinderpal Kaur, Rupesh R. Kariyat Jan 2023

Revisiting Plant Defense-Fitness Trade-Off Hypotheses Using Solanum As A Model Genus, Sakshi Watts, Satinderpal Kaur, Rupesh R. Kariyat

Biology Faculty Publications and Presentations

Plants possess physical and chemical defenses which have been found to deter herbivores that feed and oviposit on them. Despite having wide variety of defenses which can be constitutive or induced, plants are attacked and damaged by insects associated with different mouthparts and feeding habits. Since these defenses are costly, trade-offs for growth and defense traits play an important role in warding off the herbivores, with consequences for plant and herbivore growth, development and fitness. Solanum is a diverse and rich genus comprising of over 1,500 species with economic and ecological importance. Although a large number of studies on Solanum …


Bear Presence Attracts Avian Predators But Does Not Impact Lesser Snow Goose Daily Nest Attendance, Andrew F. Barnas, Brian J. Darby, David T. Iles, David N. Koons, Robert F. Rockwell, Christina A.D. Semeniuk, Susan N. Ellis-Felege Mar 2022

Bear Presence Attracts Avian Predators But Does Not Impact Lesser Snow Goose Daily Nest Attendance, Andrew F. Barnas, Brian J. Darby, David T. Iles, David N. Koons, Robert F. Rockwell, Christina A.D. Semeniuk, Susan N. Ellis-Felege

Great Lakes Institute for Environmental Research Publications

The presence of foraging bears in Arctic breeding bird colonies has been increasingly reported in the literature, and these may constitute disturbance events which cause incubating birds to leave their nest. Avian predators may associate with bears during such events, likely to capitalize on unattended nests in the presence of bears. Here, we estimated changes in daily nest attendance of lesser snow geese Anser caerulescens caerulescens in the presence of foraging bears, and estimated the association between foraging bears and avian predators. We predicted decreased nest attendance by geese on days with bears, and close associations between avian predators and …


Predation In Many Dimensions: Spatial Context Is Important For Meaningful Functional Response Experiments, Steven A. Juliano, Jonah A. Goughnour, Geoffrey D. Ower Mar 2022

Predation In Many Dimensions: Spatial Context Is Important For Meaningful Functional Response Experiments, Steven A. Juliano, Jonah A. Goughnour, Geoffrey D. Ower

Faculty Publications – Biological Sciences

For simplicity and to minimize variation, functional response experiments frequently use environments of simple physical structure and small size. Less attention is paid to similarity of the experimental environment to the natural environment where predation occurs. Assumptions about predator and prey use of space are often implied in the choice of experimental environment. We illustrate how these assumptions may affect conclusions with an experiment testing how arena size affects a functional response. Toxorhynchites rutilus preyed upon larval Culex restuans in containers differing in volume by 15x, but spanning a similar range of prey/liter. The most plausible Type II model included …


Forage Database: A Compilation Of Functional Responses For Consumers And Parasitoids, Stella Uiterwaal, Ian T. Lagerstrom, Shelby R. Lyon, John Delong Jan 2022

Forage Database: A Compilation Of Functional Responses For Consumers And Parasitoids, Stella Uiterwaal, Ian T. Lagerstrom, Shelby R. Lyon, John Delong

School of Biological Sciences: Faculty Publications

Functional responses, the relationships between consumer foraging rate and resource (prey) density, provide key insights into consumer–resource interactions while also being a major driver of population dynamics and food web structure. We present a global database of 2598 standardized functional responses and parameters extracted from the published literature. We refit the functional responses with a Type II model using standardized methods and report the fitted parameters along with data on experimental conditions, consumer and resource taxonomy and type, as well as the habitat and dimensionality of the foraging interaction. The consumer and resource species covered here are taxonomically diverse, from …


Functional Response Of Harmonia Axyridis To The Larvae Of Spodoptera Litura: The Combined Effect Of Temperatures And Prey Instars, Yasir Islam, Farhan Mahmood Shah, Ali Güncan, John Paul Delong, Xingmiao Zhou Jan 2022

Functional Response Of Harmonia Axyridis To The Larvae Of Spodoptera Litura: The Combined Effect Of Temperatures And Prey Instars, Yasir Islam, Farhan Mahmood Shah, Ali Güncan, John Paul Delong, Xingmiao Zhou

School of Biological Sciences: Faculty Publications

Functional responses are central to predator–prey dynamics and describe how predation varies with prey abundance. Functional responses often are measured without regard to prey size (i.e., body mass) or the temperature dependence of feeding rates. However, variation in prey size within populations is ubiquitous, and predation rates are often both size and temperature-dependent. Here, we assessed functional responses of larvae and adult Harmonia axyridis on the 1st, 2nd, and 3rd instars of the prey Spodoptera litura across a range of temperatures (i.e., 15, 20, 25, 30, and 35◦C). The type and parameters of the functional responses were determined using logistic …


Efficacy Of Predator Exclusion Methods And Id Of Nest Predators For Interior Least Terns And Piping Plovers At Off-Channel Nesting Sites Along The Central Platte River, Nebraska, Usa, Kaley Keldsen Sep 2021

Efficacy Of Predator Exclusion Methods And Id Of Nest Predators For Interior Least Terns And Piping Plovers At Off-Channel Nesting Sites Along The Central Platte River, Nebraska, Usa, Kaley Keldsen

Biology Theses, Dissertations, and Student Creative Activity

Nest predation is a major cause of failed shorebird reproduction. Management to increase reproductive success and survival of nesting interior least terns (Sterna antillarum athalassos; hereafter, least tern), and piping plovers (Charadrius melodus) that nest along the Central Platte River focuses on constructing and managing off-channel nesting habitats that are protected and monitored for least tern and piping plover productivity (i.e., nesting success and fledging success). However, nest and brood fates of unknown outcome, failed to unknown causes, or failed due to predation have been high for both species. These uncertainties lead to the investigation of avian and mammalian predator …


Phenotypic Diversity And Costs Of Early Hatching In Lizards, Zachary Winstead Jun 2021

Phenotypic Diversity And Costs Of Early Hatching In Lizards, Zachary Winstead

USF Tampa Graduate Theses and Dissertations

Early hatching is a form of environmentally cued hatching in which embryos can emerge early to improve chances of survival and is considered a means of antipredator defense. Early hatching as a response to predation has been well documented in amphibians, but its prevalence among other animal groups is unknown. Moreover, any trade-offs between early hatching and other traits, and thus survival, are not well understood. There is anecdotal evidence that lizards exhibit early hatching behavior, but quantitative evidence is limited to one study. In the present study, I tested for the presence of early hatching in six species of …


Switching Effects Driven By Predation On Diffusive Predator Prey System, Anal Chatterjee, Samares Pal Jun 2021

Switching Effects Driven By Predation On Diffusive Predator Prey System, Anal Chatterjee, Samares Pal

Applications and Applied Mathematics: An International Journal (AAM)

No abstract provided.


Density Dependent Growth Of Pseudomonas Fluorescens In The Presence And Absence Of C. Elegans Predation In Liquid Media, Jack Landmann Apr 2021

Density Dependent Growth Of Pseudomonas Fluorescens In The Presence And Absence Of C. Elegans Predation In Liquid Media, Jack Landmann

Honors Theses

The purpose of this study was to understand the predator-prey relationship between C. elegans worms and P. fluorescens bacteria in liquid media. We were aiming to create a predation model of the relationship between these two species.

This study was performed through three experiments. Using 96-well plates, we were able to measure the change in optical density (OD) of these wells and calculate the growth rate. This growth rate was then graphed and analyzed. The first experiment contained P. fluorescens and KB liquid media, this study demonstrated that the bacterial population has a carrying capacity. We were also able to …


Data From: Recovery From Discrete Wound Severities In Side-Blotched Lizards (Uta Stansburiana): Implications For Energy Budget, Locomotor Performance, And Oxidative Stress, Susannah S. French, Spencer B. Hudson Feb 2021

Data From: Recovery From Discrete Wound Severities In Side-Blotched Lizards (Uta Stansburiana): Implications For Energy Budget, Locomotor Performance, And Oxidative Stress, Susannah S. French, Spencer B. Hudson

Browse all Datasets

Wounding events (predation attempts, competitive combat) result in injuries and/or infections that induce integrated immune responses for the recovery process. Despite the survival benefits of immunity in this context, the costs incurred may require investment to be diverted from traits contributing to immediate and/or future survival, such as locomotor performance and oxidative status. Yet, whether trait constraints manifest likely depends on wound severity and the implications for energy budget. For this study, food intake, body mass, sprint speed, and oxidative indices (reactive oxygen metabolites, antioxidant capacity) were monitored in male side-blotched lizards (Uta stansburiana) healing from cutaneous wounds of discrete …


Spiders (Araneae) Collected As Prey By The Mud-Dauber Wasps Sceliphron Caementarium And Chalybion Californicum (Hymenoptera: Sphecidae) In Southeastern Nebraska1, Tyler B. Corey, Earl Agpawa, Eileen Hebets Jan 2021

Spiders (Araneae) Collected As Prey By The Mud-Dauber Wasps Sceliphron Caementarium And Chalybion Californicum (Hymenoptera: Sphecidae) In Southeastern Nebraska1, Tyler B. Corey, Earl Agpawa, Eileen Hebets

Eileen Hebets Publications

Predator diets represent a potential interaction between local prey availability, prey antipredator defenses, and predator foraging behavior. Female spider-specialist muddauber wasps (Hymenoptera: Sphecidae) collect spiders and provision them intact, but paralyzed, to their developing larvae, providing a unique means of quantifying the diversity and abundance of prey that they capture. Mud-dauber wasps are hypothesized to be a major source of selection on antipredator defenses in web-building spiders, and the spiny and thickened abdomens of female spiny orb-weaving spiders (Araneae: Araneidae) are hypothesized to function as antiwasp defenses. We inventoried spider prey from nests of the mud-dauber wasps Sceliphron caementarium (Drury) …


Trophic Cascades Alter Eco-Evolutionary Dynamics And Body Size Evolution, Thomas M. Luhring, John Delong Nov 2020

Trophic Cascades Alter Eco-Evolutionary Dynamics And Body Size Evolution, Thomas M. Luhring, John Delong

School of Biological Sciences: Faculty Publications

Trait evolution in predator–prey systems can feed back to the dynamics of interacting species as well as cascade to impact the dynamics of indirectly linked species (eco-evolutionary trophic cascades; EETCs). A key mediator of trophic cascades is body mass, as it both strongly influences and evolves in response to predator–prey interactions. Here, we use Gillespie ecoevolutionary models to explore EETCs resulting from top predator loss and mediated by body mass evolution. Our four-trophic-level food chain model uses allometric scaling to link body mass to different functions (ecological pleiotropy) and is realistically parameterized from the FORAGE database to mimic the parameter …


Predators As Agents Of Selection And Diversification, Jerald B. Johnson, Mark C. Belk Oct 2020

Predators As Agents Of Selection And Diversification, Jerald B. Johnson, Mark C. Belk

Faculty Publications

Predation is ubiquitous in nature and can be an important component of both ecological and evolutionary interactions. One of the most striking features of predators is how often they cause evolutionary diversification in natural systems. Here, we review several ways that this can occur, exploring empirical evidence and suggesting promising areas for future work. We also introduce several papers recently accepted in Diversity that demonstrate just how important and varied predation can be as an agent of natural selection. We conclude that there is still much to be done in this field, especially in areas where multiple predator species prey …


Identification Of Predation Events In Wild Fish Using Novel Acoustic Transmitters, Amy A. Weinz, Jordan K. Matley, Natalie V. Klinard, Aaron T. Fisk, Scott F. Colborne Aug 2020

Identification Of Predation Events In Wild Fish Using Novel Acoustic Transmitters, Amy A. Weinz, Jordan K. Matley, Natalie V. Klinard, Aaron T. Fisk, Scott F. Colborne

Great Lakes Institute for Environmental Research Publications

Background: Acoustic telemetry is a commonly used tool to gain knowledge about aquatic animal ecology through the study of their movements. In telemetry studies researchers must make inferences regarding the movements and the fates of tagged animals. Until recently, predation has been inferred in telemetry data using a variety of methods including abrupt changes in movement patterns or habitat use. An acoustic telemetry transmitter has been developed to detect predation events of tagged animals, and while they have performed well in controlled laboratory trials, literature regarding the application of these novel transmitters in field settings is limited. The objective of …


The Effects Of Leaf Litter On Predation Cue Response In Gray Tree Frog Tadpoles, Hyla Versicolor, Dani Mccauley Apr 2020

The Effects Of Leaf Litter On Predation Cue Response In Gray Tree Frog Tadpoles, Hyla Versicolor, Dani Mccauley

Undergraduate Distinction Papers

Plant litter is an important resource for consumers, particularly in freshwater environments where it influences the development processes of larval amphibians. Leaf litter alters the physiochemical environment by lowering dissolved oxygen while increasing nitrogen, tannin, and phenolic acid levels. Many anuran species show plastic responses to the threat of predation. This is communicated through a kairomone when a tadpole is consumed, allowing surviving tadpoles to alter their behavior and morphology to evade predators. The purpose of this study was to analyze the interactive effects of leaf litter and predation on gray treefrog tadpoles (Hyla versicolor). The chemical output of the …


Predator-Based Selection And The Impact Of Edge Sympatry On Components Of Coralsnake Mimicry, Lauren E. Wilson Jan 2020

Predator-Based Selection And The Impact Of Edge Sympatry On Components Of Coralsnake Mimicry, Lauren E. Wilson

Electronic Theses and Dissertations

Studying warning coloration and mimicry is an effective way to understand predator-driven selection and phenotypic diversity. The presence (sympatry) or absence (allopatry) of a toxic model plays a role in shaping mimetic phenotypes. However, the impact of edge sympatry and allopatry on predation of mimetic phenotypes is not well understood. We studied coralsnake mimicry to test how edge sympatry and allopatry affect predation on mimetic phenotypes. Specifically, we tested 1) if overall attack rates varied with edge sympatry of coralsnakes 2) which color patterns conferred a fitness advantage 3) which specific mimetic signal components are important in driving predatory attacks …


Trade-Offs Between Morphology And Thermal Niches Mediate Adaptation In Response To Competing Selective Pressures, Stella F. Uiterwaal, Ian T. Lagerstrom, Thomas M. Luhring, Miranda E. Salsbery, John P. Delong Jan 2020

Trade-Offs Between Morphology And Thermal Niches Mediate Adaptation In Response To Competing Selective Pressures, Stella F. Uiterwaal, Ian T. Lagerstrom, Thomas M. Luhring, Miranda E. Salsbery, John P. Delong

School of Biological Sciences: Faculty Publications

Abstract

The effects of climate change—such as increased temperature variability and novel predators—rarely happen in isolation, but it is unclear how organisms cope with multiple stressors simultaneously. To explore this, we grew replicate Paramecium caudatum populations in either constant or variable temperatures and exposed half to predation. We then fit thermal performance curves (TPCs) of intrinsic growth rate (rmax) for each replicate population (N = 12) across seven temperatures (10°C–38°C). TPCs of P. caudatum exposed to both temperature variability and predation responded only to one or the other (but not both), resulting in unpredictable outcomes. These changes in …


Trade-Offs Between Morphology And Thermal Niches Mediate Adaptation In Response To Competing Selective Pressures, Stella F. Uiterwaal, Ian T. Lagerstrom, Thomas M. Luhring, Miranda E. Salsbery, John P. Delong Jan 2020

Trade-Offs Between Morphology And Thermal Niches Mediate Adaptation In Response To Competing Selective Pressures, Stella F. Uiterwaal, Ian T. Lagerstrom, Thomas M. Luhring, Miranda E. Salsbery, John P. Delong

School of Biological Sciences: Faculty Publications

The effects of climate change—such as increased temperature variability and novel predators—rarely happen in isolation, but it is unclear how organisms cope with mul- tiple stressors simultaneously. To explore this, we grew replicate Paramecium caudatum populations in either constant or variable temperatures and exposed half to predation. We then fit thermal performance curves (TPCs) of intrinsic growth rate (rmax) for each replicate population (N = 12) across seven temperatures (10°C–38°C). TPCs of P. caudatum exposed to both temperature variability and predation re- sponded only to one or the other (but not both), resulting in unpredictable outcomes. …


Territorial Behavior Of The Ozark Zigzag Salamander, Plethodon Angusticlavius, Altered By Mode Of Predator Cue And Sex Of Intruder, Sarah E. Heimbach May 2019

Territorial Behavior Of The Ozark Zigzag Salamander, Plethodon Angusticlavius, Altered By Mode Of Predator Cue And Sex Of Intruder, Sarah E. Heimbach

MSU Graduate Theses

Territorial defense in many species must be balanced with trade-offs in activities such as reproduction and predator avoidance. Adjusting behavior based on current assessments of predation risk and the cost of maintaining or gaining a territory is one way that individuals can balance trade-offs to maximize fitness. I conducted two experiments to determine how Ozark zigzag salamanders, Plethodon angusticlavius, adjust their territorial behavior-based predation risk. First, I tested whether male and female territorial intruders changed their competitive behavior according to whether predation risk is assessed via unimodal (chemical) or multimodal (chemical + physical) cues. Females and males responded differently to …


Using Molecular Diet Analysis To Inform Invasive Species Management: A Case Study Of Introduced Rats Consuming Endemic New Zealand Frogs, Bastian Egeter, Cailín Roe, Sara Peixoto, Pamela Puppo, Luke J. Easton, Joana Pinto, Phillip J. Bishop, Bruce C. Robertson May 2019

Using Molecular Diet Analysis To Inform Invasive Species Management: A Case Study Of Introduced Rats Consuming Endemic New Zealand Frogs, Bastian Egeter, Cailín Roe, Sara Peixoto, Pamela Puppo, Luke J. Easton, Joana Pinto, Phillip J. Bishop, Bruce C. Robertson

Biological Sciences Faculty Research

The decline of amphibians has been of international concern for more than two decades, and the global spread of introduced fauna is a major factor in this decline. Conservation management decisions to implement control of introduced fauna are often based on diet studies. One of the most common metrics to report in diet studies is Frequency of Occurrence (FO), but this can be difficult to interpret, as it does not include a temporal perspective. Here, we examine the potential for FO data derived from molecular diet analysis to inform invasive species management, using invasive ship rats (Rattus rattus) …


Comparing Feeding Accuracy Between High And Low Predation Trinidad Guppies, Lydia J. Bonnell Apr 2019

Comparing Feeding Accuracy Between High And Low Predation Trinidad Guppies, Lydia J. Bonnell

Honors College Theses

Efficient feeding accuracy could increase an organism’s survival. Although local adaptation in Trinidad guppies is common, the effects on accuracy are unknown. Guppies were wild caught in 2015 and 2017, filmed while capturing prey. Accuracy wasn’t different within samples but differed across samples, possibly due to the prey types used.


The Demographic And Life-History Costs Of Fear: Trait-Mediated Effects Of Threat Of Predation On Aedes Triseriatus, Geoffrey D. Ower, Steven A. Juliano Mar 2019

The Demographic And Life-History Costs Of Fear: Trait-Mediated Effects Of Threat Of Predation On Aedes Triseriatus, Geoffrey D. Ower, Steven A. Juliano

Faculty Publications – Biological Sciences

  1. Predators alter prey populations via direct lethality (density-mediated effects), but in many taxa, the indirect nonlethal threat of predation may be almost as strong an effect, altering phenotypically plastic traits such as prey morphology, behavior, and life history (trait-mediated effects). There are costs to antipredator defenses and the strength of prey responses to cues of predation likely depends on both the perceived level of risk and food availability.
  2. The goal of this study was to test the hypothesis that the costs of nonlethal trait-mediated interactions impacting larvae can have carryover effects that alter life-history traits, adult characteristics, and ultimately population …


Lower Rotational Inertia And Larger Leg Muscles Indicate More Rapid Turns In Tyrannosaurids Than In Other Large Theropods, Eric Snively, Haley O'Brien, Donald M. Henderson, Heinrich Mallison, Lara A. Surring, Michael E. Burns, Thomas R. Holtz Jr., Anthony P. Russell, Lawrence M. Witmer, Philip J. Currie, Scott A. Hartman, John R. Cotton Feb 2019

Lower Rotational Inertia And Larger Leg Muscles Indicate More Rapid Turns In Tyrannosaurids Than In Other Large Theropods, Eric Snively, Haley O'Brien, Donald M. Henderson, Heinrich Mallison, Lara A. Surring, Michael E. Burns, Thomas R. Holtz Jr., Anthony P. Russell, Lawrence M. Witmer, Philip J. Currie, Scott A. Hartman, John R. Cotton

Research, Publications & Creative Work

Synopsis: Tyrannosaurid dinosaurs had large preserved leg muscle attachments and low rotational inertia relative to their body mass, indicating that they could turn more quickly than other large theropods.

Methods: To compare turning capability in theropods, we regressed agility estimates against body mass, incorporating superellipse-based modeled mass, centers of mass, and rotational inertia (mass moment of inertia). Muscle force relative to body mass is a direct correlate of agility in humans, and torque gives potential angular acceleration. Agility scores therefore include rotational inertia values divided by proxies for (1) muscle force (ilium area and estimates of m. caudofemoralis …


Density And Distribution Of Piscivorous Fishes In The Sacramento – San Joaquin Delta, Christopher M. Loomis Jan 2019

Density And Distribution Of Piscivorous Fishes In The Sacramento – San Joaquin Delta, Christopher M. Loomis

Cal Poly Humboldt theses and projects

Predatory fishes, including numerous introduced species, are common to the Sacramento – San Joaquin Delta, but abundance data for most species is insufficient to determine the Delta-wide distribution and ecological impacts of these species. Predatory fishes (e.g. Striped Bass, Largemouth Bass have long been suspected of contributing to the decline of native species, including salmonids, but data has been insufficient to investigate this hypothesis. In this study, I present a novel method to assess predator fish populations across the southern Delta using DIDSON acoustic cameras and analyze the environmental associations that form the landscape and fine-scale distribution of predatory fishes. …


Modeling The Effect Of Post-Dispersal Seed Predation On Tropical Tree Species In Panama, Justin Tirrell Dec 2018

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 …