Master of Science in Biological Sciences, Youngstown State University, 2024, Department of Biological Sciences and Chemistry

Black-tailed prairie dogs (Cynomys ludovicianus) excavate burrow systems for predatory avoidance and social organization. As such, they have evolved a suite of musculoskeletal traits in their forelimbs that are employed for scratch-digging (i.e., digging motion performed by alternating power and recovery strokes). However, the degree to which their muscular anatomy has become modified in response to the selective pressures of their semi-fossorial lifestyle is unknown. To better understand the functional capacities of their forelimb musculature, dissections of C. ludovicianus (N=9) were conducted to quantify limb mechanical advantage, muscle architectural properties, and myosin heavy chain (MHC) isoform content. Compared with previous data from ground squirrels, forelimb muscle mass distribution is broadly similar with a large investment of scapular and shoulder muscle mass that accounts for two-thirds of the total forelimb muscle mass. The majority of muscles have long fascicles with correspondingly high LF/ML ratios, whereas aside from FCR and ECU, the main digital flexors/extensors, selected intrinsic shoulder flexors/extensors, and the smallest elbow extensors, most muscles have low PCSA/MM ratios. Notably, only the massive PECS was considered to be a high-power muscle by its architectural properties, although several muscles are modified for large joint torque or torque range, including PECS, LAT, and a well-developed m. triceps brachii long head. Mechanical advantage is correspondingly greatest at the shoulder joint, appreciable at the elbow joint, and low at the carpal joint. Lastly, muscle composition is faster-contracting by moderate expression of fast MHC-2B and low expression of slow MHC-1. That said, %MHC isoform content shows a predominance of MHC-2A as predicted, which progressively increases distally throughout the forelimb. These findings collectively suggest that C. ludovicianus is less-specialized among burrowing rodents as hypothesized. Its forelim (open full item for complete abstract)

Committee: Michael Butcher PhD (Advisor); Thomas Diggins PhD (Committee Member); Jillian Tall PhD (Committee Member) Subjects: Animal Sciences; Animals; Biology; Biomechanics; Comparative; Comparative Literature; Experiments; 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

Master of Science (MS), Bowling Green State University, 2019, Biological Sciences

Crayfish use burrows for predator avoidance, desiccation prevention, foraging, and brood care. Based on their burrow ecology, species of crayfish can be categorized as tertiary, secondary, or primary burrowers. Primary burrowers are semi-terrestrial and highly dependent on burrows for survival. Secondary and tertiary burrowers have decreased burrow dependence and complexity. While most literature provides information about the function of burrows, there has been limited investigation into specifics of burrow structure. The purpose of this study is to describe burrow structure of four crayfish species: the primary burrowing species Lacunicambarus diogenes Girard, 1852 and Creaserinus fodiens Cottle, 1863, and the tertiary burrowing species Faxonius rusticus Girard, 1852 and Faxonius propinquus Girard, 1852. In the field, 17 crayfish burrows were filled with polyester resin. Cured burrow casts were excavated, and photogrammetry was used to recreate casts as 3-D models. Burrow depth, number and widths of openings, number and widths of chambers, and number of branches were recorded. Multiple factor analysis (MFA) was performed on burrow casts, with response variables separated into two groups: soil particle classification and burrow characteristics. In regard to variance in data, 33.1% was explained by dimension one (burrow size), and 20.9% was explained by dimension two (fine-grained sediment). On the MFA plot, 95% confidence interval ellipses for F. rusticus and F. propinquus overlapped, with both ellipses to the left of the vertical axis and below the horizontal axis. The C. fodiens ellipse was to the left of the vertical axis and above the horizontal axis. The L. diogenes ellipse was to the right of the vertical axis, and the mean was above the horizontal axis. Each species was also found to create a stereotyped burrow shape. This study contributes to the growing body of work on crayfish burrow structure, which has implications for future work on crayfish biology.

Committee: Paul Moore PhD (Advisor); Moira van Staaden PhD (Committee Member); Daniel Wiegmann PhD (Committee Member) Subjects: Biology; Ecology

Master of Science, University of Akron, 2011, Biology

Physiological development is a function of an organism's genotype, its environment, and the interaction between these two factors. Assessing the relative influence of these factors on an animal's physiology has occupied researchers for decades. Clonal offspring, such as those in the nine-banded armadillo (Dasypus novemcinctus) provide a unique opportunity to essentially eliminate genotypic variation and focus on environmental causes of physiological variation. Typically, variation in offspring physiology is significantly less within litters than between litters, a phenomenon known as the “sibling effect”. Ten D. novemcinctus neonates were removed from their mother following birth and hand-reared in identical environments. As juveniles, the armadillos, comprised of four litters, were exposed to acute hypoxia/hypercapnia, mimicking severe burrow conditions, and O2 consumption and CO2 production were measured via flow through respirometry. The physiological challenge of burrow conditions provides a view of sibling variation under stress. Although, the gas stressor in this study was acute, the burrow conditions in the wild are chronic for neonates. Resting O2 consumption and CO2 excretion were also measured to determine mass-specific basal metabolic rate (BMR). D. novemcinctus is known for having a lower mass-specific BMR and lower body temperature in comparison to other mammals. Although adult armadillos have been reported as a unique mammal in regards to energetics, the armadillo juveniles follow the same trends as other mammalian neonates and juveniles. Armadillo juveniles, similar to other mammalian juveniles, follow a trend toward decreased mass-specific BMR over time. When exposed to acute hypoxia/hypercapnia, an increase in mass-specific O2 consumption and mass-specific CO2 production was seen in all armadillo juveniles, consistent with previous research of neonatal mammals exposed to hypoxia and hypercapnia. By controlling the neonatal environment (i.e. feeding (open full item for complete abstract)

Committee: Brian Bagatto Dr. (Advisor); Francisco Moore Dr. (Committee Member); Rolando Ramirez Dr. (Committee Member) Subjects: Biology