Master of Public Health, The Ohio State University, 2021, Public Health

In production industries, such as aquaculture, there is a lack of invertebrate animal regulation, even with the Red Swamp Crayfish (Procambarus clarkii), which accounts for over $200 million in business for the United States. To Louisiana, crayfish are not only a crucial part of their rich culture, but also an important aspect of their aquaculture industry. Despite this, limited knowledge is available about the potential risks associated with eating farm-raised crayfish in the United States. Current food safety guidance lacks the information specific to crayfish populations within the United States allowing for the correct identification of potential hazards. In addition to food safety, biosecurity and biosafety practices associated with crayfish used in laboratory animal settings are limited. The objectives of this study are to evaluate the specific zoonotic pathogens present on Red Swamp Crayfish (Procambarus clarkii) from the southeastern part of the United States, Alabama & Louisiana, and determine the effectiveness of pathogen reduction in traditional food preparation techniques. Crayfish and their shipping containers were sampled for the presence of Escherichia coli, Salmonella, Staphylococcus aureus, and Vibrio spp. Additional subsets of crayfish were dissected to look for Paragonimus kellicotti. Vibrio was the most prevalent bacteria cultured. One hundred percent of samples collected from live crayfish (60/60) and 81% of all environmental samples (13/16) resulted in characteristic growth. Additionally, only 5% (3/60) samples grew characteristic E. coli colonies. It was also found that traditional cooking techniques were effective in reducing pathogen load in crayfish. One hundred percent (10/10) of live crayfish samples taken before boiling returned characteristic growth of Vibrio, while 10% (1/10) of boiled unseasoned crayfish samples grew minimally characteristic colonies. The remaining zoonotic pathogens, P. kellicotti, Salmonella, and S. aureus were not (open full item for complete abstract)

Committee: Thomas Wittum (Advisor); Raphael Malbrue (Committee Member); Antoinette Marsh (Committee Member); Jennifer Hefner (Committee Member) Subjects: Microbiology; Public Health; Veterinary Services

Master of Science, The Ohio State University, 2021, Environment and Natural Resources

As the dominant consumers of leaf litter in streams, crayfish play a critical role in the transformation of energy by breaking down leaf material. Yet the replacement of native crayfish by non-natives can result in the alteration of ecosystem processes. In particular, the non-native Rusty crayfish, Faxonius rusticus, has been shown to reduce standing leaf litter stocks in streams outside of their native range. Additionally, leaf breakdown rates by crayfish may be species-specific, driven by differences in behavioral traits. Non-native Rusty crayfish have begun to competitively displace native Sanborn crayfish, Faxonius sanbornii, in Ohio. The impact of this species replacement on leaf breakdown is poorly understood. Here, my two main objectives were to 1) determine species-level differences in behavioral and physiological traits in Rusty and Sanborn crayfish related to foraging, and 2) determine species-level differences in leaf consumption and decomposition rates in a stream dominated by Rusty crayfish and a stream dominated by Sanborn crayfish. I predicted that if Rusty crayfish are bolder than Sanborn crayfish, they would consume more prey items and excrete more than Sanborn crayfish. Additionally, I predicted that if Rusty crayfish consumed more prey items than Sanborn crayfish, they would consume more leaf material and accelerate leaf decomposition at sites where they were present. To test these predictions, I completed a series of laboratory experiments to quantify differences in boldness, foraging behavior, and excretion in Rusty and Sanborn crayfish. I also quantified leaf consumption between species. Finally, I completed a field leaf pack experiment to quantify leaf decomposition in one stream dominated by Rusty crayfish and one stream dominated by Sanborn. Results of my experiments suggest that there are species level differences in boldness and foraging behavior, but that excretion rates are more associated with the amount of prey consumed and differences (open full item for complete abstract)

Committee: Lauren Pintor (Advisor); Mazeika Sullivan (Committee Member); Suzanne Gray (Committee Member) Subjects: Aquatic Sciences; Behaviorial Sciences; Biology; Conservation; Environmental Science; Environmental Studies; Freshwater Ecology; Natural Resource Management

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, The Ohio State University, 2021, Environment and Natural Resources

Environmental heterogeneity in stream conditions and anthropogenic stressors, such as species introductions, can lead to intraspecific variation in traits of stream-dwelling crayfish. The rusty crayfish, Faxonius rusticus, and virile crayfish, Faxonius virilis, are distributed across a wide geographic range largely due to introductions outside of the native ranges. Previous research on these two species have demonstrated significant intraspecific variation in behavior traits across populations of both species. In this study I investigated: 1) whether behavioral differences across populations of the rusty crayfish are associated with their invasion status (e.g. native vs non-native), and 2) what environmental drivers (predation risk, resource availability, and climate) are associated with variation in behavior of both rusty and virile crayfish. I predicted that selection during the invasion process would result in non-native rusty crayfish being bolder, more active, and foraging more than native rusty crayfish, and that there would be less variance in behavior in non-native crayfish than native crayfish. I predicted that crayfish behavioral traits would be predictably associated with differences in predation risk, resource availability, and climate across populations. Furthermore, I predicted that crayfish from sites with lower predation pressure, sites with poor resource availability, and colder sites would be more bold, active and forage more than crayfish from sites with higher predation pressure, sites with abundant resource availability, and warmer sites respectively. To test whether behavior varied as a function of invasion status and environmental drivers, I quantified behavioral differences across multiple populations of rusty and virile crayfish from streams across the Midwest. Furthermore, at each stream, I measured predation pressure, macroinvertebrate resource availability, benthic algal resource availability, stream temperature, and crayfish density. I f (open full item for complete abstract)

Committee: Lauren Pintor (Advisor); Mažeika Sullivan (Committee Member); Lindsey Reisinger (Committee Member); Robert Gates (Committee Member) Subjects: Aquatic Sciences; Behavioral Sciences; Ecology; Environmental Science

Doctor of Philosophy, The Ohio State University, 1970, Graduate School

Committee: Not Provided (Other) Subjects: Biology

Master of Science, The Ohio State University, 1971, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science, The Ohio State University, 1971, Graduate School

Committee: Not Provided (Other) Subjects:

Master of Science (MS), Bowling Green State University, 2024, Biological Sciences

Fertilizers rich in nitrogen and phosphorus have been implicated in toxic algal blooms and the eutrophication of Lake Erie. One method for mitigating nutrient runoff is the use of wetlands. Wetlands sequester and process nutrients via biogeochemical processes, decreasing the concentrations of nutrients that eventually reach a large body of water. Research on nutrient cycling in aquatic systems has mainly focused on the sediment, the plants, and the water. Few consider the potential impacts of animals in the system despite the evidence that animals play an important role in nutrient cycling in freshwater systems. Animals can directly move nutrients in and out of aquatic systems, as well as indirectly affect the nutrient budget by altering the ecosystem. The combined direct and indirect effects of animal-mediated nutrient cycling in a wetland system have not been adequately assessed. A few wetland mesocosm experiments have examined the influence of animals on wetland nutrient cycling, but most focus on one functional feeding group. In this study, I evaluated the role of aquatic macroinvertebrates from two functional feeding groups in wetland nutrient sequestration using in-field mesocosms containing macrophytes, in the recently constructed H2Ohio wetland at Oakwoods Nature Preserve (Findlay, OH, USA). Nitrogen and phosphorus content of the water column was measured over six days in response to the presence of each invertebrate. Six replicates of three treatments (snails, crayfish, or control) were installed for a total of 18 mesocosms. A nutrient pulse was added to mesocosms at the end of the experiment to mimic natural nutrient dynamics in an agricultural-adjacent wetland system and nutrient uptake was measured. The results suggest that the crayfish treatment altered nutrient cycling, increasing total nitrogen and total phosphorus iv levels and a decreasing light transmission. These changes could be attributed to bioturbation as the crayfish cre (open full item for complete abstract)

Committee: Kevin McCluney Ph.D. (Advisor); Christopher Ward Ph.D. (Committee Member); Helen Michaels Ph.D. (Committee Member) Subjects: Biology; Conservation; Ecology; Freshwater Ecology

PHD, Kent State University, 2023, College of Arts and Sciences / Department of Biological Sciences

Over the past few decades, the massive anthropogenic increase in PPCP consumption and their subsequent release, ubiquitous distribution, and pseudo-persistence in the environment have compelled many people to monitor PPCPs in rivers, lakes, drinking water, groundwater, and sediments. PPCPs can also enter drinking water treatment plants via either surface water or sometimes through groundwater. Despite their widespread distribution, PPCP monitoring is not mandatory in DWTPs according to federal or state regulations in the US, thereby limiting our understanding of PPCP occurrence, distribution, and subsequent removal in DWTPs. The removal of PPCPs in DWTPs also depends on the specific treatment processes (conventional or advanced) and the molecular structures of the removed compounds. Despite some studies focusing on PPCP occurrence and removal from DWTPs, there is still a significant knowledge gap regarding compound-specific removal of PPCPs both seasonally and treatment-wise (conventional vs. advanced). There is also insufficient knowledge about the removal of mixed PPCPs in sand-anthracite biofilters, particularly for drinking water. Moreover, their effects (microbial and biochemical) on benthic aquatic invertebrates are not well investigated. The overall goal of this dissertation was to understand the distribution of PPCPs in the surface and drinking water, their chemical and biological removal from water, and their effects on benthic aquatic invertebrates. Specifically, I aimed to understand how PPCPs are distributed in the surface and drinking waters of Northern Ohio, how they are removed from the finished waters in water treatment plants, how microbial community changes with the removal and/or interactions of PPCPs from drinking water in sand-anthracite biofilters and finally how PPCPs induce microbial and biochemical changes in freshwater crayfish.

Committee: Xiaozhen Mou Ph.D (Advisor); Laura Leff Ph.D (Advisor) Subjects: Chemistry; Ecology; Microbiology

Master of Science (MS), Bowling Green State University, 2023, Biological Sciences

Agonistic interactions between individuals are influenced by a variety of complex factors both internal and external. Due to the complex nature of interactions, it can be difficult to determine the specific driving factors that influence the outcome of agonistic interactions. In many species, physical and chemical signals are utilized to deliver specific cues to potential opponents and mitigate interactions. In aquatic systems chemical signals are often used and designed to be carried by the flow of the water to deliver ranged information. This information can include status, sexual availability, aggression, and other important cues that may not be discernable in the water column through other channels. Crustaceans are a well-known group for modeling dominance hierarchies due to their overt demonstrations for dominance and repetition of agonistic behaviors over time. The goal of this research was to investigate the role that chemical cue reception plays in determining dominance in agonistic interactions in female crayfish. To accomplish this, we generated groups of individuals and grouped them by size, form, and species to receive either the control or ablation treatment. Chemosensory ablation removed the animal's ability to detect chemical signals with their antennules through an extensive lesioning process which lysed the cells on that sensory organ. We discovered that lesioning of the antennules resulted in changes in duration and level of escalation of agonistic interactions among the crayfish species tested. Additionally, the size of the crayfish was a contributing factor to the duration and intensity of the interaction. Lesioned crayfish of larger size spend longer at low intensity agonistic behavior, likely due to the loss of chemical information from lesioning.

Committee: Paul Moore Ph.D. (Committee Chair); Rachelle Belanger Ph.D. (Committee Member); Daniel Pavuk Ph.D. (Committee Member) Subjects: Behaviorial Sciences; Biology; Communication

Master of Science (MS), Bowling Green State University, 2023, Biological Sciences

Selective serotonin reuptake inhibitors (SSRI) are a growing group of pollutants that are increasingly causing detrimental changes to aquatic ecosystems. Upon entering aquatic habitats, these chemicals affect both vertebrates and invertebrates by influencing fecundity, aggression, exploration, and mortality in non-target organisms. In crustaceans, more specifically in crayfish and lobsters, since serotonin (5-Hydroxytryptamine, 5-HT) has been linked to a suite of stress responses and agonistic behaviors, SSRIs have the potential to harm these organisms significantly. In this study, we aimed to quantify the effects of a twenty-one day exposure of citalopram on the behavior and physiology of the rusty crayfish (Faxonius rusticus). Crayfish were exposed to an environmentally relevant concentration (1 μg / L) of citalopram in their tank water for 21 days and perform physiological (oxygen consumption and stress analysis) and behavioral (flight initiation distance) assays. Changes in behavior (reaction distance), physiology (oxygen consumption), and neurotransmitter levels (stress) were used to quantify any effects due to citalopram exposure. We found that as the length of exposure increased, regardless of citalopram presence, the oxygen consumption rate decreased significantly. Females that were injected with supplemental 5-HT froze closer to a novel stimulus than males or individuals from other treatment groups. Females also took longer to explore the arena than males, regardless of treatment. The amount of 5-HT present in individuals increased with mass, but this was not observed in individuals exposed to an external stressor regardless of the presence or absence of citalopram in their system. Exposure to 1 μg / L of citalopram for 21 days did not significantly impact crayfish behavior, but behavior and oxygen consumption were impacted by sex and isolation length, respectively. While this concentration of citalopram did not alter behavior or physiology, further work is (open full item for complete abstract)

Committee: Paul Moore Ph.D (Committee Chair); Anya Goldina Ph.D (Committee Member); Verner Bingman Ph.D (Committee Member) Subjects: Biology; Ecology; Experiments; Freshwater Ecology; Neurobiology; Organismal Biology; Pharmaceuticals; Toxicology

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2022, Biological Sciences

Chemical exposure and the effects toxicants have on organisms is often described by the magnitude or concentration at which the toxicant is applied. However, other components of exposure paradigms, such as the duration and frequency of exposure events also contribute to the overall toxicological effects seen in behavior and physiology of impacted organisms. Additionally, joint toxic action of multiple toxicants in the form of complex mixtures can lead to higher or lower toxicity than what is predicted by the concentration curves of individual mixture components and complicates discussions about risk assessment of multiple stressors. My dissertation investigated the role of the main components of chemical exposure, magnitude, duration, and frequency, in shaping the effects to behavior and physiology of Faxonius rusticus, the rusty crayfish. Finally, in order to address complex mixtures, a binary mixture of two common pharmaceutical compounds was applied to crayfish to determine if joint toxic action was occurring and affecting behavior and physiology.

Committee: Paul Moore Ph.D. (Committee Chair); Robert Huber Ph.D. (Committee Member); Louise Stevenson Ph.D. (Committee Member); Robert Satterlee Ph.D. (Other); Raymond Larsen Ph.D. (Committee Member) Subjects: Biology

Master of Science (MS), Bowling Green State University, 2022, Biological Sciences

Northwest Ohio has been heavily impacted by ditching and draining of the landscape as well as impoundment and pond construction. These features can reduce baseflows, alter wetland hydroperiods, or otherwise impair ecosystem services. However, they may also create aquatic habitat, serve as refuges from wetland habitat loss and promote connectivity of wildlife populations. It is critical to identify the effects of hydromodification on semiaquatic fauna such as the common muskrat (Ondatra zibethicus), the American mink (Neovison vison) and cambarid crayfishes (Cambaridae), which may be sensitive to associated changes in fine- and coarse-scale wetland habitat and landscape characteristics. To evaluate potential wetland habitat use patterns, sign and nocturnal spotlight surveys were conducted in the Oak Openings Region from May 15th to October 18th 2021. Habitat, environmental and spatial data were also collected. As predicted, focal organisms used modified wetlands to a lesser degree, although the effect depended on organism and wetland type. As expected further, muskrats and crayfishes were more likely to use higher order or deep streams/ditches; crayfishes were more likely to use seasonal and restored wetlands. Results were consistent with isolation-area based predictions of habitat use insofar as mink and muskrats were more likely to use large nonlinear wetlands, and muskrats used less isolated wetlands. Crayfish and, unexpectedly, mink used more isolated wetlands. Open canopy and anthropogenic landcover classes in the landscape neighborhood of wetlands featured in many habitat use models. Fine-scale habitat variables tended to predict habitat use as well as or better than coarser-scale variables. Treating presence or relative activity of each organism as a predictor variable in habitat use models of the other organisms produced competitive models, although results for mink occurrence were inconsistent with predictions based on predator-prey relationships. Results su (open full item for complete abstract)

Committee: Karen Root Ph.D. (Committee Chair); Enrique Gomezdelcampo Ph.D. (Committee Member); Jeffrey Miner Ph.D. (Committee Member) Subjects: Biology; Ecology; Wildlife Conservation; Wildlife Management

Master of Science (MS), Bowling Green State University, 2022, Biological Sciences

Organisms use chemical cues in their environment to extract relevant information in order to perform a variety of tasks. To forage effectively, organisms must locate and assess the quality of food sources based on these chemical cues. When determining the quality of these food sources, crayfish use chemical cues in the form of amino acids to both locate food and to determine consumption. However, whether crayfish foraging in flowing systems is altered by differing amino acid concentration is currently unknown. Rusty crayfish collected from two different watershed locations were exposed to fish gelatin containing increasing concentrations of the amino acid β-Alanine (attractive amino acid) and L-Tyrosine (aversive amino acid). The gelatin was weighed before and after each 24-hour trial to determine consumption. The addition of an attractive amino acid (β-Alanine) caused a significant drop in consumption but only for crayfish collected from one of the locations (p = 0.04). The addition of an aversive amino acid (L-Tyrosine) had no effect on crayfish consumption from either location. This study demonstrates that the foraging and feeding behaviors of organisms are influenced by the presence of amino acids located in food sources.

Committee: Paul Moore PhD (Advisor); Karen Root PhD (Committee Member); Shannon Pelini PhD (Committee Member) Subjects: Biology; Freshwater Ecology; Organismal Biology

Master of Science (MS), Ohio University, 2020, Environmental Studies (Voinovich)

Urban stormwater runoff has become of increasing concern as urban sprawl has increased over decades. With more impervious surfaces, stormwater quickly passes into freshwater ecosystems with little to no water percolating into the soil. Even if there are not impervious surfaces, stormwater may pass over agricultural lands where nitrogen and phosphorus are easily available to flow into aquatic environments. Management plans are now using different strategies to filter out sediment and nutrients before they enter lotic or large lentic ecosystems. These small ponds or constructed wetlands have larger pieces of sediment settle before they have an opportunity to flow into a larger water body. While this has shown to be a successful and useful tool to filter out materials, horizontal (lateral) movement of water during flood events has become a concern. Species in a wetland can migrate in and out of the wetland into a lentic or lotic ecosystem, returning for refuge and breeding habits. If the wetland and larger water body become cut off they develop their own line of succession. The purpose of this study is to understand and characterize the water quality between an urban stormwater wetland and the headwaters of the Hocking River. Evaluate differences of biotic assemblages in the two water bodies and present information to the neighboring AHA! A Hands-On Adventure A Children's Museum. These goals are done by conducting: fish, invertebrate, crayfish and field parameter tests.

Committee: Natalie Kruse Daniels (Advisor); Nancy Stevens (Advisor); Kelly Johnson (Committee Chair) Subjects: Agricultural Education; Animal Sciences; Aquaculture; Aquatic Sciences; Art Education; Arts Management; Biology; Chemistry; Climate Change; Communication; Early Childhood Education; Earth; Ecology; Education; Entomology; Environmental Education; Environmental Studies; Hydrology; Industrial Arts Education; Multimedia Communications; Museum Studies; Museums; Pedagogy; Physical Education; Sustainability; Teacher Education; Teaching; Technical Communication; Urban Planning

Doctor of Philosophy (Ph.D.), Bowling Green State University, 2020, Biological Sciences

The interactions between predators and their prey are complex and drive much of what we know about the dynamics of ecological communities. When prey animals are exposed to threatening stimuli from a predator, they respond by altering their morphology, physiology, or behavior to defend themselves or avoid encountering the predator. The non-consumptive effects of predators (NCEs) are costly for prey in terms of energy use and lost opportunities to access resources. Often, the antipredator behaviors of prey impact their foraging behavior which can influence other species in the community; a process known as a behaviorally mediated trophic cascade (BMTC). In this dissertation, predator odor cues were manipulated to explore how prey use predator information to assess threats in their environment and make decisions about resource use. The three studies were based on a tri-trophic interaction involving predatory fish, crayfish as prey, and aquatic plants as the prey's food. Predator odors were manipulated while the foraging behavior, shelter use, and activity of prey were monitored. The abundances of aquatic plants were also measured to quantify the influence of altered crayfish foraging behavior on plant communities. The first experiment tested the influence of predator odor presence or absence on crayfish behavior. Crayfish spent more time foraging and less time in shelter in the presence of predator odor cues compared to predator absent controls. The crayfish also consumed greater quantities of two macrophyte species in the presence of threatening odors. In the second experiment, crayfish were exposed to odors from predators that were fed four different diets and varied in their size relative to the size of the crayfish. The crayfish responded to the relative size ratios between themselves and their predators, but the direction of the response was determined by the predator's diet. The third experiment exposed individual crayfish to odors from individual predators (open full item for complete abstract)

Committee: Paul Moore PhD (Advisor); Robert Green PhD (Other); Shannon Pelini PhD (Committee Member); Andrew Turner PhD (Committee Member); Daniel Wiegmann PhD (Committee Member) Subjects: Aquatic Sciences; Behavioral Sciences; Ecology

PHD, Kent State University, 2019, College of Arts and Sciences / Department of Biological Sciences

Today, the tranquil stillness of night or the symphony of an early morning bird chorus are likely to be replaced with the discordant sounds of automobiles, jackhammers, or water boat engines. Common human activities, such as transportation and urban construction, produce outdoor noise pollution that is unhealthy for people but also has a negative impact on nearby fauna. This understanding has led to new areas of research focus: understanding soundscape ecology and testing the effects of anthropogenic noise pollution. Many studies have examined these topics using wildlife, marine mammals, and fish. However, studies examined the effect of invertebrates on the composition of natural soundscapes and their response to anthropogenic noise pollution has not been well studied. Furthermore, early studies focused on the effect of noise pollution on a relatively few species of birds and whales. These studies have provided valuable insight into the bioacoustics ecology of many ecosystems. However, the increasing threat of anthropogenic noise pollution in freshwater ecosystems has only recently been understood. In many parts of the world, traffic is one of the biggest contributors to the increasing levels of anthropogenic noise. Researchers Arevalo and Blau studied the impact of road networks on protected areas. They found that soundscapes in many areas were directly affected by road proximity and that natural sounds were often masked near roads with heavy use or large vehicle traffic. They proposed that this contributes to the degradation of habitats through the loss of natural sounds. Others have recommended management efforts in national parks should not only maintain good quality habitat, but also preserve the natural soundscapes. Thus, research is needed to identify characteristics of natural soundscapes and also test how they are altered in areas with noise pollution. In my first study, I used recorded sound to investigate the impact that submersed aquati (open full item for complete abstract)

Committee: Ferenc de Szalay (Advisor) Subjects: Aquatic Sciences; Ecology

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 (MS), Bowling Green State University, 2019, Biological Sciences

The adoption of genetically modified (GM) crops has occurred rapidly in the United States. The transfer of GM corn byproducts from agricultural fields to nearby streams after harvest is significant and occurs well into the post-harvest year. These corn leaves, stems and cobs then become a detrital food source for organisms such as shredders in the stream ecosystem. Considering non-target effects of Bt corn have been observed in some terrestrial organisms, we aimed to assess whether Bt toxins affect an important aquatic organism, juvenile F. rusticus crayfish. Juvenile crayfish were fed six distinct diet treatments: two varieties of Bt corn, two varieties of herbicide tolerant corn, and two controls: fish gelatin and river detritus. Juveniles were fed these diets while housed in flow-through artificial streams that received natural stream water from a local source. Specific growth rate and survivorship of the crayfish were measured throughout the study. Juveniles fed corn diets grew significantly less and had reduced survival when compared to juveniles fed fish gelatin or river detritus diets. Furthermore, juveniles fed one Bt variety of corn (VT Triple Pro) exhibited significantly less growth than those fed one of the herbicide tolerant varieties (Roundup Ready 2). Our study shows that corn inputs to streams near agricultural fields may be detrimental to the growth and survivorship of juvenile crayfish and that certain Bt varieties may exacerbate these negative effects. These effects on crayfish will have repercussions for the entire ecosystem, as crayfish are conduits of energy between many trophic levels.

Committee: Paul Moore PhD (Advisor); Eric Hellquist PhD (Committee Member); Helen Michaels PhD (Committee Member) Subjects: Agriculture; Environmental Science

Master of Science (MS), Bowling Green State University, 2018, Biological Sciences

Prey often alter their morphology, physiology, and/or behavior when presented with predatory cues. Alteration in behaviors (i.e. habitat use, food consumption) are consequences of non-consumptive effects that can alter the dynamics of prey resources and cause changes in food web structures. One key factor in determining predation threat level by predators is the composition of the diet of the predator. We wanted to test the ability of prey to determine threat level based on cues produced by different predators on various diets. Odors from two different species of fish, bass (Micropterus salmoides), a natural predator of crayfish, and cichlid (Oreochromis aureus x Oreochromis niloticus), a non-natural predator of crayfish that were fed a vegetarian pellet, a protein diet, a heterospecific crayfish, and a conspecific crayfish were collected. Anti-predator behavior was tested by placing the prey, crayfish (Orconectes virilis), in a y-maze and analyzing the side of choice arena the crayfish spent time in, shelter usage of the crayfish, walking speed, walking forward and backward, climbing, and posture when presented with predator odors. Our results show that crayfish spent less time in odors containing conspecific diets, but when in this odor, crayfish spent most of the time hiding in the shelter when odors were emitted from a natural bass predator. However, these results were not present when exposed to non-predatory cichlid odors. Therefore, crayfish can determine different threat levels based off of chemical signals emitted from a potential or real threat, when paired with diet, eliciting predator avoidance behaviors.

Committee: Paul A. Moore Dr. (Advisor); Verner P. Bingman Dr. (Committee Member); Daniel D. Wiegmann Dr. (Committee Member) Subjects: Animals; Behavioral Sciences; Biology; Ecology; Freshwater Ecology