Doctor of Philosophy, University of Akron, 2024, Integrated Bioscience

In this thesis, a novel type of hydraulically-actuated robophysical model was used to test hypotheses concerning the relationship between head kinematics and the force and work required for burrowing through damp granular media by amphisbaenians, a clade of mostly limbless, burrowing squamates. The design of the robot was intended to mimic a simplified, limbless body plan similar to that found among burrowing squamates, having an extendable cylindrical shaft and an oscillating, bullet-shaped head. Forces and work of an actuated head and shaft were compared while forward penetration occurred simultaneously with head oscillation amplitudes of 5, 10, and 15 degrees from a centerline, at a ratio of 1 and 2 oscillations per push distance, and compared to a control group with no head movement. An intermittent push strategy was also investigated in which the oscillation of the head was decoupled from the forward penetration of the shaft so that the machine alternated between a forward push and a head oscillation phase. The distance traveled by the robot between each oscillation phase was varied, and force and work were observed for distances of 2cm, 4cm, and 8cm between each oscillation phase, with either 1 or 2 head oscillations per phase. The peak force experienced, and the total work done by the shaft decreased with a 15 degree head oscillation amplitude, but any reduction in these variables is more than offset by the increase in force and work required to rotate the head. Amphisbaenians are a relatively diverse clade, well adapted to subterranean locomotion, but despite their diversity they are understudied. Understanding the significance of head kinematics could be informative for bioinspired digging machines, and could shed light on the biology of the animals. Meanwhile, the suitability of crushed, expanded perlite as a proxy for other damp granular media in laboratory experiments was explored, with implications for similar experiments as well as interpreting data fr (open full item for complete abstract)

Committee: Henry Astley (Advisor); Petra Gruber (Committee Member); Julian Tao (Committee Member); Rachel Olson (Committee Member); Philip Bergmann (Committee Member); Peter Niewiarowski (Committee Member) Subjects: Biology; Biomechanics; Robotics

Master of Science in Biological Sciences, Youngstown State University, 2021, Department of Biological Sciences and Chemistry

Geomyid and heteromyid rodents demonstrate a range of limb morphology. In particular, subterranean/fossorial pocket gophers have hypertrophied forelimbs with large mechanical advantage (MA) for burrowing, whereas those of semi-fossorial pocket mice and kangaroo rats are smaller in size and lack MA, yet these taxa are capable of digging elaborate burrow systems similar to gophers. To better understand the functional capacity of their forelimb musculature, dissections of Botta's pocket gopher (Thomomys bottae; N = 10), desert pocket mouse (Chaetodipus penicillatus; N = 5), and Merriam's kangaroo rat (Dipodomys merriami; N = 3) were conducted to quantify limb MA, muscle architectural properties, and myosin heavy chain (MHC) isoform content. As expected, metrics indicating MA varied significantly larger in T. bottae than in both C. penicillatus and D. merriami. With the exception of the humeral retractors, however, the latter two taxa generally have longer, parallel fascicles and shorter moment arms in the power stroke muscle functional groups resulting in larger fascicle length to muscle length (LF/ML) and fascicle length to moment arm (LF/rm) ratios than pocket gophers. Nevertheless, the humeral retractors of C. penicillatus and D. merriami are observed to have large force per unit mass by physiological cross-section area to muscle mass (PCSA/MM) ratios nearly 2x those of T. bottae. PCSA/MM ranged from 1.0–3.0 in all pocket mouse and K-rat muscle groups analyzed. MHC content is also notably faster in C. penicillatus and was the only species to express fast MHC-2B, where as slow MHC-1 isoform expression was low, but specific to T. bottae. All three species mainly expressed fast MHC-2A and -2X with each isoform showing some relationship with body size. The findings provide evidence that pocket mice and K-rats compensate for their lack of MA by their forelimb muscles being capable of both large intrinsic contractile velocity and size-scaled force production, which match (open full item for complete abstract)

Committee: Michael Butcher PhD (Advisor); Thomas Diggins PhD (Committee Member); Alexis Moore-Crisp PhD (Committee Member) Subjects: Anatomy and Physiology; Biology; Biomechanics; Zoology

Doctor of Philosophy, The Ohio State University, 2021, Evolution, Ecology and Organismal Biology

The overarching goal of my dissertation is to ameliorate the North American primary burrowing crayfish taxonomic impediment by describing new species and revising taxonomic classifications. I specifically focus on revising the taxonomy of Cambarus diogenes and other members of what I provisionally term the Devil Crayfish Group (DCG) using an integrative taxonomic approach. My work elucidates the evolutionary relationships between the species in this group and generates a robust taxonomic framework that will help managers identify and prioritize species for conservation. In chapter 2, I take the first steps towards resolving the taxonomy of the DCG by testing the hypothesis that this group is monophyletic through phylogenetic analyses of mitochondrial DNA sequence data (mtDNA) from multiple specimens of the eight DCG species and a broad sampling of taxa representing approximately 70% of the species in what is currently recognized as the genus Cambarus. My analyses show that seven of the eight species from the DCG form a clade that is distinct from the remainder of what has traditionally been recognized as Cambarus. Based on these results and on unique morphological and ecological characteristics, I split seven of the eight DCG species from Cambarus and elevate the subgenus Lacunicambarus to generic rank to accommodate them. I redescribe Lacunicambarus and the devil crayfish sensu stricto (Lacunicambarus diogenes comb. nov.) and designate a neotype for the species to facilitate subsequent revisionary work. In chapters 3, 4 and 5, I continue my investigation of what is now the genus Lacunicambarus. In each case, I increase depth and breadth of my sampling as I gradually collect additional specimens to use in my morphological and molecular analyses. As my datasets increase in size, so too does my understanding of Lacunicambarus, allowing me to describe several new species. Specifically, in chapter 3, I describe the Crawzilla Crawdad, Lacunicambarus chimera, a specie (open full item for complete abstract)

Committee: Marymegan Daly (Advisor); Rachelle Adams (Committee Member); Catherine Montalto (Committee Member); John Freudenstein (Advisor) Subjects: Animals; Biology; Ecology; Environmental Science; Evolution and Development; Systematic; Zoology

Master of Science (MS), Ohio University, 2021, Geological Sciences

Studies of the relationship between extant trace makers, known environmental conditions, and the morphology of their biogenic structures allow for the interpretation of continental ichnofossils. This study examined the burrowing techniques, behaviors, and trace morphologies of three extant species of burrowing beetles, Tenebrio molitor, Zophobas morio, and Phyllophaga sp., from their larval to adult life stages under normal and stressed environmental conditions in a laboratory setting. Tenebrio molitor and Z. morio burrowed using their mandibles to compact the substrate, while Phyllophaga sp., burrowed by excavation and backfilling. The three species primary behaviors were locomotion, mobile deposit feeding, intermittent resting, and pupation. Larvae burrows of T. molitor and Z. morio included open boxworks, while Phyllophaga sp. larvae generated elongate backfilled burrows which terminated in an open chamber. All three species created ovoid to ellipsoidal chambers when preparing for pupation. During their adult stage, T. molitor and Z. morio created conical traces and chambers, while Phyllophaga sp. produced loosely backfilled burrows. The environmental stresses tested were related to sediment sand and water content as well as sediment compactness. Higher trace abundance was produced in sediments with decreased sand content, increased water content, and low compactness, although trace morphologies did not change. Highly compacted substrates had little activity, but distinct trace morphologies. The total level of bioturbation, quantified with the ichnofabric index, produced by multiple specimens of each species in large enclosures filled with layered sediment varied from 1 (T. molitor and Phyllophaga sp.) to 2-5 (Z. morio). Quantitative analyses of the quantitative properties of the different traces showed that, despite having similar morphologies, the traces produced by the three species were dissimilar, but also showed variation within species. Understanding extan (open full item for complete abstract)

Committee: Daniel Hembree Ph.D (Advisor); Alycia Stigall Ph.D (Committee Member); Xizhen Schenk Ph.D (Committee Member) Subjects: Geology; Paleontology

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2016, Biological Sciences

The ability to navigate successfully to and from sites rich in resources is essential for survival for many organisms. In particular, the ability to repeatedly locate a shelter is critical for avoiding predation. Way finding behaviors are observed across the animal kingdom, with both vertebrates and invertebrates demonstrating highly efficient methods of navigating. The spatial scale of the movement may vary with some animals traveling several hundred kilometers while others may only need to travel a few meters. With a rich behavioral repertoire and relatively simple nervous system crayfish prove to be excellent models for comparative research. Studies have demonstrated their abilities to learn locations in arenas using both place and response cues. However, relatively little is known about crayfish in terms of their abilities to return to shelters from foraging excursions. The work presented here aimed to explore the behavioral mechanisms utilized by crayfish when homing to their burrows. Additionally, this study examined two comparative species of crayfish, both of which utilize burrows, but only one constructs the burrows (primary burrowers). More specifically are there differences in their abilities to navigate to the burrows? The crayfish species were selected based on the varying complexity of the environments within which they reside as well as the amount of energy invested in constructing burrows. The research conducted as part of this dissertation highlighted that i) crayfish do home to artificially constructed burrows within a lab setting ii) there were differences in homing behavior between two species with differing use of burrows (highlighting differences in their behavioral ecology) iii) homing to burrow was not based on a local cue associated directly with the burrow and iv) the mechanism for homing to burrows may be similar in both species. The goal of this dissertation was to examine short range homing behaviors in both a primary and tertiary (open full item for complete abstract)

Committee: Paul Moore (Advisor); Verner Bingman (Committee Member); Wendy Manning (Other); Shannon Pelini (Committee Member); Daniel Wiegmann (Committee Member) Subjects: Biology; Ecology; Neurosciences

Master of Science, University of Toledo, 2006, Biology (Ecology)

It is well known that invasive species, such as the dreissenid mussels in the Great Lakes, play significant roles in changing the substrate, community species composition, and habitat. This study examined the role of Dreissena, (zebra mussel, D. polymorpha and quagga mussel, D. bugensis) as an invasive “paver”, which compacts the sediment, and its effects on two native bioturbators, Hexagenia (burrowing mayflies; H. limbata and H. rigida) and unionid bivalve mollusks. Resulting consequences on sediment properties, infaunal invertebrates, and microbial community composition were analyzed. I further examined the spatial relationship between Dreissena and Hexagenia. Experiments showed that Hexagenia density increased in the presence of Dreissena, nematodes decreased, and oligochaetes and microbes were unaltered. In the absence of Dreissena, bioturbating species altered sediment water content and increased infaunal invertebrate densities, microbial activity, and microbial functional diversity. In further exploration of the relationship between Dreissena and Hexagenia, Hexagenia preferred habitat with 50-100% spatial coverage of live Dreissena clusters. These experiments thus revealed habitat facilitation by an invasive ecosystem engineer on a native ecosystem engineer, Hexagenia, with opposite effects on invertebrates, microbes, and sediment properties.

Committee: Christine Mayer (Advisor) Subjects: