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Sitvarin, Michael IanBehavioral and ecological consequences of multiple intraguild predators and connections between predators, prey, and ecosystem function
Doctor of Philosophy, Miami University, 2014, Zoology
Prey species sit at a pivotal point in food webs, serving as a connection between predators and energy sources (e.g., plants or detritus). Most prey face multiple predators and must integrate information about predation risk if they are to avoid being consumed. Meanwhile, predators interact with one another and can increase or decrease their combined pressure on prey. By interacting with their prey, predators can indirectly affect ecosystem functions, even without reducing prey population size. The goal of my dissertation was to understand how prey survive in a world with multiple predators and to uncover linkages between predators and the soil food web. I first tested hypotheses about how the wolf spider Pardosa milvina responds to cues from multiple predators (the larger wolf spider Tigrosa helluo and the ground beetle Scarites quadriceps) and how inaccurate information regarding predation threat affects survival. Pardosa were capable of distinguishing between predators and responding adaptively, though prey responses were not optimized when predators were at elevated hunger levels. As a second step, I allowed multiple predators (the wolf spider Rabidosa rabida along with Tigrosa and Scarites) to freely interact with each other and their prey (Pardosa) to test the influence of predator characteristics and the occurrence of intraguild predation on prey survival. Overall, I found support for a predictive framework of emergent multiple predator effects, though intraguild predation events caused significant deviations from model predictions. I also investigated the consumptive and nonconsumptive effects predators can have on their environment, focusing on the detrital food chain. The presence of either Pardosa or their cues impacted CO2 flux and soil nitrogen content as mediated by the detritivore Sinella curviseta, suggesting indirect top-down control of ecosystem function by predators. Finally, I tested the response of Sinella to cues indicating predation risk to determine if changes in detritivore activity linked predators to ecosystem function. Sinella responded innately to necromones but did not alter activity levels in the presence of Pardosa cues, even after a conditioning period.

Committee:

Ann Rypstra, Ph.D. (Advisor); Nancy Solomon, Ph.D. (Committee Member); Brian Keane, Ph.D. (Committee Member); Tom Crist, Ph.D. (Committee Member); Dave Gorchov, Ph.D. (Committee Member)

Subjects:

Biology; Ecology; Entomology; Organismal Biology; Soil Sciences; Zoology

Keywords:

predation; ecology; behavior; predator; prey; nonconsumptive effects; intraguild predation; emergent multiple predator effects; activity; survival; ecosystem function; soil respiration; soil nitrogen content; trait-mediated interaction; interference

Thieme, Jennifer LeeBehavioral and reproductive consequences of predator activity to grassland birds
Master of Science, The Ohio State University, 2011, Environment and Natural Resources
Grassland birds are declining at greater rates than any other habitat guild in North America, yet conservation remains difficult due to extensive habitat loss and fragmentation throughout the urbanizing Midwest. Human presence is often associated with non-native predators (e.g., cats) and anthropogenic food sources, which collectively can promote high densities of nest predators in urban landscapes. High densities of nest predators are a concern because predation is the leading source of nest failure. Behavioral responses to predators may further diminish the value of urban habitats if birds avoid areas with high levels of predator activity, which could result in lower occupancy rates or densities of birds in urban habitat patches. In my research, I examined how habitat heterogeneity and variation in the predator community influenced the breeding ecology of grassland and early successional birds in urban parks. I asked two broad questions: (1) how do birds respond behaviorally to abundance and activity of predators in urban natural areas? (2) to what extent is avian reproductive success linked to predator communities and/or activity at plot and site scales? I collected data on avian density, nest placement, and reproductive success of eight focal species of grassland birds within 46 2-ha plots at seven urban parks near Chicago, Illinois, during 2009 and 2010. Relative abundance and activity levels of potential nest predator species, including mesopredators, small mammals, snakes, and avian predators, were estimated for each plot during surveys and as part of a collaborative study. As capture rates of small mammals increased, territory densities of Field Sparrow (Spizella pusilla), Common Yellowthroat (Geothlypis trichas), and Savannah Sparrow (Passerculus sandwichensis) declined, but density of Song Sparrow (Melospiza melodia) rose. Mesopredator capture rates were negatively associated with Common Yellowthroat and Savannah Sparrow densities within 2-ha plots, as well as Eastern Meadowlark (Sturnella magna) at the site level. Whereas small mammal and mesopredator capture rates explained some of the observed variation in territory density, daily nest survival of both Field and Song Sparrows was best explained by numbers of snakes observed within plots. Interestingly, snake activity was positively associated with nest survival of Field Sparrows, though negatively associated with that of Song Sparrows. At large scales, vegetation characteristics best predicted nest survival of both species, with nest survival of Field Sparrow improving as density of groundcover increased and nest survival of Song Sparrow improving as structural complexity increased. While the structural complexity of vegetation at nest sites was not explained by predator activity, Song Sparrows selected nest sites with lower groundcover density than available as activity of Brown-headed Cowbird (Molothrus ater) increased. As a whole, these results provide evidence that breeding grassland and early successional birds respond to both habitat structure and activity of potential predators at different scales. I also found that behavioral (e.g., territory selection) and demographic (e.g., nest survival) associations with predators do not necessarily match. For example, snakes had the strongest, though sometimes counterintuitive, relationship with nest success of Field and Song Sparrows, yet appeared to elicit no response during territory or nest site selection. My results are also consistent with other studies demonstrating the importance of vegetation structure to both settlement and reproductive success. Consequently, the best management practices in urban parks will both maintain vegetation structure that promotes successful nesting and discourage activities that promote high abundances of predators.

Committee:

Amanda Rodewald (Advisor); Stanley Gehrt (Other); Jacqueline Augustine (Other)

Subjects:

Ecology

Keywords:

predator; prey; avian; nest success; grassland; bird; reproduction; territory selection; mesopredator; nest site selection; daily survival

Guo, MengyuPredator-Induced Changes of the Green Frog (Rana clamitans)'s Diet Preference
Master of Sciences, Case Western Reserve University, 2016, Biology
Phenotypic plasticity occurs when organisms change their behavior, morphology and life history in response to environmental variation. This study aims to answer three questions: 1.how do diets with different protein content influence green frog tadpoles’ body mass; 2. how does the presence and absence of predators affect tadpoles’ diet preference; 3. how do predators affect growth and survivorship of tadpoles. In experiment I, tadpoles were exposed to three food treatments to measure the amount of food consumed, diet preference, growth, and survivorship. In experiment II, tadpoles were exposed to predator cues to compare the amount of food consumed, diet preference, growth, and survivorship in presence and absence of predators. Green frog tadpoles responded to predation risk by reducing the amount of food consumed, reducing growth, and decreasing survivorship. We found that tadpoles preferred high protein food in the absence of predator and lowered total consumption of protein food when exposed to predator.

Committee:

Michael Benard (Advisor)

Subjects:

Animal Sciences; Behaviorial Sciences; Ecology

Keywords:

Predator effects, Diet preference, Green frog

Maran, Audrey MPredator Contributions to Belowground Responses to Warming
Master of Science (MS), Bowling Green State University, 2015, Biological Sciences
Identifying the factors that control soil carbon dioxide emissions will improve our ability to predict the magnitude of climate change-soil ecosystem feedbacks. Despite the integral role of invertebrates in belowground systems, they are excluded from climate change models. Soil invertebrates have consumptive and non-consumptive effects on microbes, whose respiration accounts for nearly half of soil carbon dioxide emissions. By altering the behavior and abundance of invertebrates that interact with microbes, invertebrate predators may have indirect effects on soil respiration. This research examined the effects of a generalist arthropod predator on belowground respiration under different warming scenarios. Based on research suggesting invertebrates may mediate soil carbon dioxide emission responses to warming, predator presence was predicted to result in increased emissions by negatively affecting these invertebrates. Presence of the predator, wolf spiders (Pardosa spp.), was manipulated in mesocosms containing a community of soil invertebrates. To simulate warming, we placed mesocosms of each treatment in ten open-top warming chambers ranging from 1.5 to 5.5° C above ambient at Harvard Forest, MA. Soil carbon dioxide efflux data, microbial abundance, soil moisture, and soil temperature were measured to determine the effects of predators on belowground systems. As expected, carbon dioxide emissions increased under warming and there was an interactive effect of predator presence and warming, though the effect was not consistent through time. The interaction between predator presence and temperature was the inverse of our predictions: mesocosms with predators had lower carbon dioxide emissions at higher temperatures than those without predators. Carbon dioxide emissions were not significantly associated with microbial biomass or soil moisture. There was not find evidence of consumptive effects of predators on the invertebrate community, suggesting that predator presence mediates response of microbial respiration to warming through non-consumptive means. In this system we found a significant interaction between warming and predator presence that warrants further research into mechanism and generality of this pattern to other systems

Committee:

Shannon Pelini, Dr. (Advisor); Kevin McCluney, Dr. (Committee Member); Michael Weintraub, Dr. (Committee Member)

Subjects:

Biology; Climate Change; Ecology; Soil Sciences

Keywords:

climate change; warming; predator; soil; invertebrate; insect; ecology; carbon; carbon dioxide; linear mixed effects model; respiration

Lohrey, Anne K.The Impact of Avian Predation on the Brush-Legged Wolf Spider, Schizocosa Ocreata (Hentz), and Anti-Predator Responses to Avian Cues
MS, University of Cincinnati, 2007, Arts and Sciences : Biological Sciences
This research aimed to quantify the potential for avian predation on Schizocosa ocreata wolf spiders in the field and its impact on spider behavior. In a field study, enclosures that excluded birds had a higher proportion of spiders remaining at the end of the experiment than enclosures that allowed birds access. Additionally, observational data confirmed that some bird species seen active at the study site eat spiders presented in feeding trials. These data suggest that bird predation impacts survival of S. ocreata in the field. In the laboratory, I tested spiders‘ recognition of and behavioral responses to sensory cues indicating the presence of avian predators. Courting male S. ocreata responded to avian acoustic stimuli (bird calls) with anti-predator behavior, which supports the hypothesis that bird predation limits survival of S. ocreata and may be an important selective factor on the evolution of behavior in this species of wolf spider.

Committee:

Dr. George Uetz (Advisor)

Keywords:

Animal Behavior; Avian Predation on Spiders; Anti-predator Behavior

Schlosser, Ann MargaretTHE EFFECTS OF FEMALE BODY CONDITION, FEMALE CUE AND PREDATOR CUE PRESENCE ON THE LOCOMOTIVE AND REPRODUCTIVE BEHAVIOR OF THE MALE WOLF SPIDER PARDOSA MILVINA (ARANEAE; LYCOSIDAE)
Master of Science, Miami University, 2005, Biological Sciences
Organisms constantly make behavioral decisions regarding reproduction and predator avoidance. To aid this process, males can benefit by detecting high-quality females and by using cues in the environment. Male wolf spiders (Pardosa milvina) adjusted their activity in response to chemical/tactile cues from female Pardosa. When confronted with two females simultaneously, males showed a stronger activity response to cues from females with high than low-quality body conditions. Overall, males displayed a stronger response to the cues deposited by a predator as compared to cues deposited by female Pardosa. When confronted with female and predator cues simultaneously, the graded behavioral response to cues from the high and low-quality females disappeared. Courtship and copulation behaviors of males were affected by female cue presence and body condition. However, predator cues did not affect these behaviors. These results suggest that multiple factors may affect the reproductive decision-making processes of Pardosa.

Committee:

Ann Rypstra (Advisor)

Subjects:

Biology, Zoology

Keywords:

Pardosa milvina; predator cue; female cue; female body condition; wolf spider

Wrinn, Kerri M.Impacts of an herbicide and predator cues on a generalist predator in agricultural systems
Doctor of Philosophy, Miami University, 2010, Zoology
Animals use chemical cues for signaling between species. However, anthropogenic chemicals can interrupt this natural chemical information flow, affecting predator- prey interactions. I explored how a glyphosate-based herbicide influenced the reactions of Pardosa milvina, a common wolf spider in agricultural systems, to its predators, the larger wolf spider, Hogna helluo and the carabid beetle, Scarites quadriceps. First, I tested the effects of exposure to herbicide and chemical cues from these predators on the activity, emigration, and survival of P. milvina in laboratory and mesocosm field experiments. In the presence of H. helluo cues in the laboratory, P. milvina always decreased activity and increased time to emigration. However, in the presence of S. quadriceps cues, these spiders only decreased activity and increased time to emigration when herbicide was also present. Presence of predator cues and herbicide did not affect the emigration of P. milvina from field mesocosms, but survival was highest for spiders exposed to S. quadriceps cues alone and lowest for those exposed to herbicide alone. Secondly, I tested the effects of predator cues, herbicide and prey availability on foraging and reproduction in female P. milvina. Spiders offered more prey captured and consumed more, while those exposed to H. helluo cues consumed less. Availability of prey and exposure to predator cues and herbicide in foraging trials had interactive effects on P. milvina’s subsequent reproductive success. In the low prey treatments, exposure to predator cues and herbicide each reduced reproductive success. In the high prey treatments, exposure to herbicide reduced reproductive success for spiders also exposed to S. quadriceps cues, but increased reproductive success for spiders also exposed to H. helluo cues. Finally, I exposed juvenile P. milvina to S. quadriceps cues and herbicide but found no effect of either on the spider’s growth and development. Together, these results indicate that predation risk and herbicide application likely interact in complex ways to affect the movement, reproduction and survival of a major arthropod predator in agricultural systems, and thus may have complex effects on the food web.

Committee:

Ann Rypstra, PhD (Advisor); Michelle Boone, PhD (Committee Member); Thomas Crist, PhD (Committee Member); Maria Gonazlez, PhD (Committee Member); David Gorchov, PhD (Committee Member)

Subjects:

Zoology

Keywords:

wolf spiders; glyphosate; herbicide; predator cues

Jones, Jared K.THE ALTERATION OF HABITAT USE BY CRAYFISH (ORCONECTES RUSTICUS) IN RESPONSE TO PREDATOR (ICTALURUS PUNCTATUS) CUES
Master of Science (MS), Bowling Green State University, 2012, Biological Sciences
The use of shelters by crayfish is influenced by the presence or absence of predatory cues. Crayfish are able to detect sensory cues in the environment and use the information gathered to make behavioral changes to reduce the risk of becoming a predator’s next prey item. Factors such as mechanical cues or chemical cues in the water may determine the extent to which the crayfish alter not only the use of shelter, but also other behaviors, such as walking speed and exploratory behaviors. This thesis set out to address which factor elicits the strongest response in behavior alteration and use of shelter. To tease apart the mechanical and chemical cues, five sets of trials were conducted. The first set of trials acted as a control in which a baseline of behavior and shelter use could be determined. The second set of trials exposed the crayfish to the scent of a channel catfish (Ictalurus punctatus), but not to the mechanical cues of the predator. The third set of trials exposed the crayfish to the mechanical cues of a model channel catfish, but not the chemical cues. The fourth set of trials exposed the crayfish to the chemical cues of a channel catfish and mechanical cues of the model channel catfish simultaneously. The fifth and final set of trials exposed the crayfish to the chemical and mechanical cues of a channel catfish. By observing the behaviors under the various experimental designs, the research shows us that the mechanical cues of the model channel catfish had the greatest effects on the behaviors demonstrated by the crayfish. The results from these experiments show us that the crayfish relied more on the mechanical cues in the environment than the chemical cues when considering predator avoidance and behavior modification.

Committee:

Paul Moore (Advisor); Robert McKay (Committee Member); Jeffrey Miner (Committee Member)

Subjects:

Animal Sciences; Aquatic Sciences; Behavioral Sciences; Biology

Keywords:

crayfish; catfish; predator-prey interactions; shelter use; habitat use; chemical cues; mechanical cues

Neal, Orin J.Responses to the audio broadcasts of predator vocalizations by eight sympatric primates in Suriname, South America
MA, Kent State University, 2009, College of Arts and Sciences / Department of Anthropology

The selective pressures exerted on primate populations from threat of predation have led to numerous behavioral and morphological adaptations that allow for pre-emptive detection and evasion of predators. Predators evolve counterstrategies, and an arms race is born. Anti-predator strategies are costly, in the sense that employing them may divert energy from activities more directly related to fitness, such foraging or mating. Therefore, one would expect higher frequencies of more severe anti-predator behaviors to be expressed by primates who have regular interactions with potential predators, because temporal allocation of those behaviors would be reinforced.

A snapshot of natural primate populations reveals that predation is often a substantial source of mortality. Here I investigate the anti-predator strategies of eight sympatric primates in Suriname, South America, to examine how astute wild primates are at detecting predators by only audio cues, how strategies vary by taxa, and whether these strategies vary depending on level or perception of risk within a location. The results suggest that neotropical primates can identify predators as such by vocalizations alone, that anti-predator strategies are highly variable, and that some degree of experience and reinforcement is required for an appropriate level of response behavior. Further, primates in the neotropics appear to evaluate the relative safety of their surroundings and make decisions based on them when confronted with the perceived presence of predators.

Committee:

Marilyn Norconk, PhD (Committee Chair); Richard Meindl, PhD (Committee Member); Kimberley Phillips, PhD (Committee Member)

Subjects:

Animals; Biology; Physical Anthropology

Keywords:

predation; anti-predator strategies; alarm calls

Beattie, Molly C.Diet and familiarity influence on predator recognition by chemical cues in crayfish
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

Keywords:

diet; chemical cues; predator-prey; naivety; behavior; crayfish

Duffy, Sean DavidWhy the Rise in Drones
Master of Arts (MA), Wright State University, 2015, International and Comparative Politics
What are the reasons for the increasing number of drone strikes between 2002 and 2012 by the United States? This study examines the various aspects of the United States government which led to this increase in the number of strikes. Specifically, this study examines the military capabilities, the military leadership bureaucracy and presidential aspects of drone use. Through the division of this time period into three sections, this study seeks to find explain the events which led to the increase in the use of drones by the United States. This study concludes with a discussion on what the future may hold for the United States Unmanned Aerial Combat Vehicle program.

Committee:

Vaughn Shannon, Ph.D. (Committee Chair); Jonathan Winkler, Ph.D. (Committee Member); R. William Ayres IV, Ph.D. (Committee Member)

Subjects:

International Relations; Military History; Military Studies; Political Science

Keywords:

Drones; UCAV; Robotics; Military Doctrine; UAV; Reaper; Predator; Rumsfeld; Gates; Bush; Drone Strike;

Rincon Rueda, Diego FernandoDelphastus catalinae and the silverleaf whitefly, Bemisia tabaci biotype B, on tomato: modeling predation across spatial scales
Doctor of Philosophy, The Ohio State University, 2015, Entomology
Understanding behavioral traits that determine the ability of predators to suppress pest populations at spatial scales larger than those evaluated in the laboratory may help in selecting the right species and release rates for biological control programs. My thesis is that predation rates within whole plants are driven by the interaction between prey distribution, individual predator patch-to-patch behavior and consumption rates within patch units. I propose that results derived from simple laboratory settings can be useful to predict predation rates within whole plants, if they are combined with spatially explicit descriptions of prey distribution and predator movement patterns. I assume that the leaflet is a spatial scale at which predators and prey behave as in laboratory settings, at least in experiments without replacement of consumed prey. My study extended from the leaflet to the plant scale, encompassing both the relatively homogeneous prey patch unit, leaflet, and the more structurally complex combination of leaflets, leaves, branches and main stem. My study system consisted of the silverleaf whitefly (SWF), Bemisia tabaci biotype B, and the coccinellid predator Delphastus catalinae inhabiting greenhouse tomato plants. To support my thesis, I evaluated key predator behavioral patterns by modeling the interaction between SWF spatial distribution and the search behavior of D. catalinae. First, I developed an algorithm to generate within-plant spatial distributions of the SWF, based on aggregation patterns observed within and among tomato leaves. Second, I described the spatial interaction between the SWF and D. catalinae at the within-plant scale and examined its effects on D. catalinae predation rates and functional response. I found that prey and predator prefer different plant regions and that predation rates and the functional response at the scale of a leaflet are comparable to what have been observed in the laboratory. In contrast, I observed that predation rates are lower and that the functional response changes qualitatively when the scale of observation is increased from the leaflet to the plant. To gain understanding of the processes that drive such a change in predation rates and functional response with scale transition, I developed an individual-based model that incorporates the observed behavioral patterns of D. catalinae individuals when preying on SWF nymphs within tomato plants. I found that the number of leaflets visited per plant by predators and the degree of spatial alignment between predator and prey distributions impact predation rates significantly at the spatial scale of the whole plant. Also, I demonstrated that simple measures of prey distribution and predator foraging patterns can be used to scale up functional responses estimated through laboratory settings. Altogether, my research shows that non-random distributions and movement patterns of prey and predators can be predicted, at least within plant structures, and that simple measures of such patterns can be used to accurately model predation rates within plants using observations from laboratory settings. My thesis can be applied to overcome current limitations in the extrapolation of data collected in the laboratory to the field, which ultimately will help fine-tune release procedures of biological control programs.

Committee:

Luis Canas, Ph.D. (Advisor); Casey Hoy, Ph.D (Advisor); Robin A. J. Taylor, Ph.D. (Committee Member); Laurence Madden, Ph.D. (Committee Member); Larry Phelan, Ph.D (Committee Member)

Subjects:

Ecology; Entomology

Keywords:

Algorithm; Biological control; Functional response; Intra-plant spatial distribution; Predator-prey models; Search behavior; Spatially explicit individual-based model

Kinney, Kaitlin AlyseThe role of biotic resistance through predation on the invasion success of the green porcelain crab (Petrolisthes armatus) into nearshore oyster reef communities.
Master of Science, The Ohio State University, 2017, Environment and Natural Resources
The northward spread of the non-native, invasive filter feeding crab Petrolisthes armatus into oyster reef communities along the Southeastern US is hypothesized to be limited by cold snaps associated with northern winters. However, several native predators in oyster reefs have been shown to consume this abundant and profitable prey item, suggesting that biotic resistance through predation may be an additional factor limiting its northward spread. My objectives were to 1) determine if the per capita predation risk exerted by native predators might be a factor that explains the current distribution of P. armatus, and 2) test whether the relative abundance of alternative native prey affects the consumption and preference of P. armatus by a native predatory crab Panopeus herbstii. I conducted a field study to quantify predation risk across 8 invaded estuary sites from St. Augustine, FL to North Inlet, SC and conducted a lab experiment to quantify the consumption of P. armatus when in low to high abundance relative to alternative native prey. While predation rates were high (68.2 – 98.2%) across sites, there was no relationship between predation and latitude across the 8 invaded estuaries. Furthermore, while P. herbstii increased consumption of P. armatus in response to increased abundance in the tank, P. herbstii always showed a preference for native prey regardless of its relative abundance. Overall, I found no evidence of biotic resistance through predation, suggesting that native predators do not prevent the spread of P. armatus and this species is likely to continue its expansion into northern waters as sea temperatures increase with climate change.

Committee:

Lauren Pintor, Dr. (Advisor); Stuart Ludsin, Dr. (Committee Member); Christopher Tonra, Dr. (Committee Member); James Byers, Dr. (Committee Member)

Subjects:

Ecology; Environmental Studies; Natural Resource Management

Keywords:

biological invasion; biotic resistance; green porcelain crab; Petrolisthes armatus; geographic range; nonnative species; predator-prey; optimal foraging theory

Kearns, Laura J.Avian Responses to Predator Communities in Fragmented, Urbanizing Landscapes
Doctor of Philosophy, The Ohio State University, 2012, Environment and Natural Resources
Behavioral responses to predators during the breeding season can critically affect the nest success of songbirds. However, the ability of birds to modify behavior based upon perceived and actual predation risk at multiple spatial scales (e.g. local (within-site), site, and landscape) and in novel (e.g., urban) environments remains poorly understood. In this dissertation, I explored how information about predation risk influenced the nest-site selection and nestling provisioning behavior of two species of songbirds – northern cardinals (Cardinalis cardinalis) and Acadian flycatchers (Empidonax virescens), which are two relatively common forest songbirds of eastern North America with contrasting responses to urbanization. I studied the use of information regarding predation risk and behavioral responses of birds during the 2006-2010 breeding seasons at riparian forest sites within the urbanizing landscapes of central Ohio. Specifically, I investigated the following questions: 1) how do cardinals and flycatchers choose nest locations based on information about local-scale nest predator activity patterns, 2) do cardinals and flycatchers incorporate private (i.e. detectable information only known to the individual) and public (i.e. detectable information known to all individuals) information about predation risk in nest-site selection, and 3) are provisioning rates to nestlings adjusted relative to public information about site-level predation risk? The ways that birds used information about predation risk varied with species, type of behavior, and the scale of information. Cardinals incorporated local scale information about predator activity, previous nest fate, and at times, actual predation risk at the site scale, to modify nest-site selection. They demonstrated sensitivity to information at multiple scales and an apparent ability to adjust nesting behaviors in ways that may allow them to thrive in urban areas. On the other hand, flycatchers used only local-scale predator activity information in selecting nest-sites, were less responsive to site-scale information, but likely recognized and responded to predator information or other cues of habitat quality at the landscape level when making breeding decisions. Both songbird species exhibited more cautious breeding behaviors when faced with certain types of predation risk, but seemed sensitive to the scale of predator information in choosing to do so. Thus, differences in use of information about predation risk may reflect constraints on the relative behavioral flexibility of cardinals and flycatchers. Not only does this study reveal ways in which behavioral plasticity can vary between songbirds with different affinities for urbanizing landscapes, but also illuminates the importance of studying various scales and types of information in evaluating songbird responses to predators.

Committee:

Amanda Rodewald, PhD (Advisor); Stanley Gehrt, PhD (Committee Member); Charles Goebel, PhD (Committee Member); Mazeika Sullivan, PhD (Committee Member)

Subjects:

Ecology

Keywords:

songbird;predator;information;predation risk; nest; parental care; behavioral plasticity;urbanization

Kautz, Andrea RLocal Management and Landscape Effects on the Predator Guild in Vegetable Crops, with a Focus on Long-legged Flies (Diptera: Dolichopodidae)
Master of Science, The Ohio State University, 2015, Entomology
Biological control is a vital ecosystem service provided by a diverse guild of predators in agroecosystems. Biodiversity is thought to be linked to ecosystem functioning through more efficient resource capture via niche partitioning. Understanding the factors that impact the diversity of predators in agroecosystems is therefore important to our understanding of how to enhance biological control services. Long-legged flies (Diptera: Dolichopodidae) are a particularly ubiquitous yet understudied group of insect predators that are common in all habitats in Ohio, including agricultural systems. Previous studies have shown that these flies are sensitive to environmental changes, at least in natural systems like grasslands and reed marshes. The goal of this study was to determine how local management and landscape-scale factors such as composition and heterogeneity influence the community assemblage of Dolichopodidae, and the predator community as a whole, found in agroecosystems. During the summer of 2013 and 2014, pan trapping was used to sample the long-legged fly community present in produce farms across northeast Ohio that represented a gradient of landscape complexity and management intensity. Communities found within sweet corn, summer squash, and unmanaged old fields were surveyed. Over 3,000 flies representing eleven dolichopodid genera and 33 species were found across both years. Dolichopodid abundance was actually higher in crop habitats than unmanaged habitats, but habitat preference varied by genus. Landscape factors influencing the abundance of Dolichopodidae varied from year to year. Identifying which factors are driving the diversity of this family of flies will help us understand how to maximize the biological control services being provided. During the same time, above-ground and ground dwelling predators were also sampled in sweet corn and summer squash using yellow sticky cards and pitfall traps in order to quantify the predator guild as a whole. Over 26,000 predatory arthropods were counted over the two summers. Predator abundance was generally higher in squash, but community composition varied between crops. Therefore, crop diversity in a farmscape may be important for supporting a diverse predator guild. In general, more agricultural habitat in the surrounding landscape had a negative effect on the predator guild, so diversification at the landscape scale may also be an important way to promote diverse predator guilds and biological control services.

Committee:

Mary Gardiner, PhD (Advisor); Celeste Welty, PhD (Committee Member); Norman Johnson, PhD (Committee Member)

Subjects:

Agriculture; Ecology; Entomology

Keywords:

Dolichopodidae, long-legged flies, predator guild, biological control, agroecosystems, biodiversity ecosystem function, landscape composition, farm management, vegetable crops, entomology

Shortridge, Megan GDiet Analysis of Maumee River Fishes using Cytochrome C Oxidase (COI) DNA Metabarcoding ― Insights into a Critical Time of Year
Master of Science (MS), Bowling Green State University, 2016, Biological Sciences
In recent years, DNA barcoding, the sequencing of a common marker region for taxonomic identification, has become integrated into U.S. agency protocols and procedures. Chapter 1 provides an overview of areas where DNA barcoding is currently being used by U.S. agencies to address questions of management concern; the benefits and limitations of using barcoding in an agency setting are considered, as well as how the technology may evolve in the near future. A diet metabarcoding study was then conducted in Chapter 2, which addressed a question of fisheries management concern, the diet of Maumee River fishes at an important time of year using cytochrome c oxidase (COI) DNA metabarcoding, with a particular focus on detecting predation on early life stages (ELS) of walleye (Sander vitreus). DNA amplified from the homogenized gut contents of fishes captured in the Maumee River during early spring was analyzed using next generation sequencing. Walleye eggs and larvae were present when predators were collected, although at lower densities than previously reported at peak density in the Maumee River. Despite the presence of walleye ELS in the system, the number of fishes with sequences assigned to walleye was lower than initially expected. One female white perch (Morone americana), one male white bass (Morone chrysops), and two emerald shiners (Notropis atherinoides) that were caught in the spawning grounds (Orleans Park) had gut content sequences assigned to walleye. Relatively low density of walleye in the system, the presence of alternative prey items (e.g., chironomids), lower overall feeding intensity by predator fishes near the onset of spawning, and/or turbidity in the Maumee River acting as a predation refuge may explain the lower than expected predation on walleye ELS, however, this requires further investigation and confirmation. Overall, sequences assigned to 7 phyla of metazoans were detected using DNA metabarcoding, including 9 genera of chironomids. Unexpected diet items were encountered, including potential predation on the bryozoan, Plumatella casmiana, by emerald shiner. This study reinforced the utility of DNA barcoding in providing insight where morphological identification is difficult as described in Chapter 1, but also points to areas where methods need improvement.

Committee:

Jeff Miner (Advisor); Daniel Heath (Committee Member); Michael McKay (Committee Member); Christine Mayer (Committee Member)

Subjects:

Biology; Ecology; Molecular Biology; Zoology

Keywords:

walleye; Maumee River; Lake Erie; DNA barcoding; DNA metabarcoding; predator-prey interaction; predation; fish; emerald shiner; white bass; white perch; sportsfish; recruitment; fisheries management; next generation sequencing;

Clark, JessicaThe Sensory Mechanisms of Crayfish (Orconectes rusticus) Used in Detecting Predatory Threats
Master of Science (MS), Bowling Green State University, 2017, Biological Sciences
Organisms are exposed to numerous environmental stimuli in which they must be able to distinguish threats from food sources. In order to make such distinctions, organisms rely upon sensory mechanisms, including chemoreception, vision, and mechanoreception. With the reception of chemical, visual, and/or mechanical cues prey species can determine the location, size, and movement of a nearby predator. Then, with the information gathered, prey can determine the severity of the threat and respond accordingly, whether to flee or to display a defensive stance. Various studies suggest that several aquatic species, including crayfish, rely on the integration of sensory modalities to accurately assess predatory threats. This study aimed to determine whether a hierarchy in the reliance upon sensory modalities exists in crayfish (Orconectes rusticus) and if this hierarchy is altered across different sensory environments (such as flowing and non-flowing environments). We also sought to determine the significance of sensory multimodality in crayfish. To study the relevance of each of the sensory modalities, as well as the integration of these modalities, in crayfish combinations of lesions/blocks were conducted. Two sensory mechanisms (chemical and mechanical, chemical and visual, or visual and mechanical) were lesioned/blocked at once, leaving one sensory mechanism (vision, mechanoreception, or chemoreception) functional. Each of the crayfish were then exposed to a predatory largemouth bass (Micropterus salmoides) in either a flowing or non-flowing stream where their behavior was recorded for 30 minutes. The behaviors and movements of the crayfish were then analyzed with the use of Ethovison Noldus XT. Linear mixed models were then conducted to determine the impact of the lesions, flowing environments, and the combination of iv the lesions and flowing environments on the ability of crayfish to detect predatory stimulus. Significant Least Squares Means (LSM) test were followed by Type II Wald Chisquare tests. Results from this study support the significance of sensory multimodality in crayfish for accurately detecting and assessing predatory threats. When the sensory multimodality of crayfish was eliminated the animals were challenged to successfully assess the severity of the predator. Crayfish with only the full use of chemoreceptors or mechanoreceptors showed a greater avoidance of the predator, indicating that these individuals could detect the threat but could not accurately locate the source. Results from this study also suggest that a hierarchy in the reliance upon sensory modalities does exist in crayfish, with a bias towards chemoreception, followed by mechanoreception, and finally vision.

Committee:

Paul Moore (Advisor); Jeffrey Miner (Committee Member); Daniel Wiegmann (Committee Member)

Subjects:

Aquatic Sciences; Behavioral Sciences; Biology; Ecology

Keywords:

sensory modalities; multimodality; sensory hierarchy; crayfish;predator-prey interactions; nonconsumptive effects

Jurcak, Ana MDefining the reaction space of predator-prey interactions
Doctor of Philosophy (Ph.D.), Bowling Green State University, 2018, Biological Sciences
This dissertation contributed to the call for a greater comprehension of sensory ecology within predator-prey interactions, particularly in the non-consumptive effects (NCEs) of predators. I investigated how stimulus modality, predator movement, environmental transmission, prey sensory ecology, pollution, and the interaction of these factors modify prey behavioral responses to predators. Specifically, I experimentally tested three research questions: 1) how the reaction space of predators with different hunting modes in different flow environments altered prey behavior, 2) how modulating signal intensity and prey detection thresholds altered the reaction space, and 3) how the exposure to anthropogenic chemicals altered the reaction space of prey. First, I placed prey (crayfish) in two different environments (flow and no flow) in one of three predator treatments (active predator [bass], sit-and-wait predator [catfish], no predator) and monitored the behavior of the crayfish in a resource patchy environment. Predator hunting mode changed prey behavior, but only in flowing water that would enhance the transmission of predator cues. The most significant interaction between predator treatment and flow environment was found with the active predator in flowing habitats, but this same interaction did not alter NCEs from a sit-and-wait predator. Second, I exposed virile and rusty crayfish to low, medium, or high concentration of odor from largemouth bass and to controls without bass odor and monitored crayfish. The results showed that the behavior of virile crayfish was significantly altered across concentrations more than rusty crayfish, indicating that the virile crayfish may have larger reaction space. Finally, I exposed virile and rusty crayfish to a pesticide (carbaryl) then placed the crayfish in a two-choice flume containing predator odor and clean river water to monitor their behavior. I found that the exposure to a carbaryl did not affect the anti-predator behavior of either species. The findings show that each factor of the reaction space is important in understanding and altering NCEs of predators. Additionally, NCEs may be hidden unless the interaction of factors is taken into consideration. Investigating the sensory environment of predator-prey interactions is crucial for better understanding the mechanisms driving the NCEs of predators and their consequences.

Committee:

Paul Moore (Advisor); Emily Freeman Brown (Committee Member); Jeffrey Miner (Committee Member); Shannon Pelini (Committee Member); Delbert Smee (Committee Member)

Subjects:

Biology

Keywords:

reaction space; predator-prey; NCEs;

Pavlic, Theodore P.Optimal Foraging Theory Revisited
Master of Science, The Ohio State University, 2007, Electrical Engineering
Optimal foraging theory explains adaptation via natural selection through quantitative models. Behaviors that are most likely to be favored by natural selection can be predicted by maximizing functions representing Darwinian fitness. Optimization has natural applications in engineering, and so this approach can also be used to design behaviors of engineered agents. In this thesis, we generalize ideas from optimal foraging theory to allow for its easy application to engineering design. By extending standard models and suggesting new value functions of interest, we enhance the analytical efficacy of optimal foraging theory and suggest possible optimality reasons for previously unexplained behaviors observed in nature. Finally, we develop a procedure for maximizing a class of optimization functions relevant to our general model. As designing strategies to maximize returns in a stochastic environment is effectively an optimal portfolio problem, our methods are influenced by results from modern and post-modern portfolio theory. We suggest that optimal foraging theory could benefit by injecting updated concepts from these economic areas.

Committee:

Kevin Passino (Advisor)

Keywords:

robotics; automation; autonomous vehicles; behavior; behavioral ecology; intelligent control; portfolio theory; modern portfolio theory; MPT; post-modern portfolio theory; PMPT; optimal foraging theory; OFT; optimal diet selection; predator; prey

Kennedy, Sara IWhite-tailed Deer (Odocoileus virginianus) Fawn Survival and Seasonal Movement Patterns of White-tailed Deer and Coyotes (Canis latrans) in the Cleveland Metropolitan Area
Master of Science, The Ohio State University, 2015, Environment and Natural Resources
White-tailed deer (Odocoileus virginianus) and coyotes (Canis latrans) are challenging wildlife species to manage in urban areas. Deer often reach densities which exceed cultural and ecological carrying capacities. Varied public opinions of both species present additional challenges. Cleveland Metroparks implements a population model to guide management efforts to reduce deer densities. However, two elements of the model lacking reliable estimates are fawn survival and migration across park boundaries. Also, the influence of coyotes on deer dynamics is unknown for urban systems. To develop better estimates of survival and habitat use and to understand the coyote-deer relationship, we conducted a multi-year study to quantify coyote and doe movement and fawn survival. Six coyotes were collared with GPS transmitters. Twenty-nine adult deer were captured; seven pregnant does received a radio collar and vaginal implant transmitter. Fifty-seven neonatal fawns were captured and fitted with expandable radio collars. We recorded 22 fawn mortalities. Vehicle strikes and culling were the most common causes of mortality. Average six month survival was 78%. Factors with the potential to influence fawn survival were modeled using known-fate models in Program Mark in a two-step process, first incorporating intrinsic covariates and then adding spatial and habitat covariates to the best-supported model from the first step. The best supported models varied with the time period of the analysis, but all included age class. Additional covariates included in one or more top models included habitat composition, home range size, and road density. Habitat use and selection were examined on a seasonal basis. For does, location data was divided into pre-parturition and post-parturition. Fawn locations were examined at three age classes: birth to two weeks, two to eight weeks, and older than eight weeks. Coyote locations were classified into three periods of differing levels of fawn vulnerability: pre-fawn (March – April), hiding (May – June), and fleeing (July – August). For coyotes, we calculated overlap indices between seasonal home ranges and core use areas. Both does and fawns used natural habitat out of proportion with availability. Both showed little seasonal change in habitat use or selection, although some does increased their use of open habitat post-parturition. Habitat use by fawns showed more variation between individuals than between seasons. Coyotes showed substantial individual variation in all spatial metrics, but a majority increased their use of forested habitat during the hiding period. Seasonal overlap indices varied from 6.2% to 82.5% for home ranges and from 0.0% to 42.9% for core use areas. Improved estimates of population parameters for urban white-tailed deer can aid in management of this potentially overabundant species. Our work demonstrates that fawn survival can be high in urban areas and reinforces the link between urban parkland and surrounding residential areas for managing urban wildlife.

Committee:

Stanley Gehrt (Advisor); Jeremy Bruskotter (Committee Member); Stephen Matthews (Committee Member); Terry Robison (Committee Member)

Subjects:

Animals; Biology; Ecology; Natural Resource Management; Wildlife Conservation; Wildlife Management

Keywords:

white-tailed deer, Odocoileus virginianus, coyote, Canis latrans, urban ecology, fawn survival, spatial ecology, predator-prey, ecology of fear

Malpass, Jennifer SEffects of food and vegetation on breeding birds and nest predators in the suburban matrix
Doctor of Philosophy, The Ohio State University, 2015, Environment and Natural Resources
The expansion of urbanization globally has prompted scientists to examine the effects of human developments on wildlife communities, often using birds as a focal taxa. My research investigates population and community-level consequences of anthropogenic food and vegetation resources in the suburban matrix, focusing on breeding birds and their nest predators. I combine observational and experimental approaches to test how anthropogenic subsidies and habitat modification affect avian population demography and predator-prey interactions, and compare these patterns between developed (i.e. residential yards) versus undeveloped (i.e. forested parks) areas within suburban landscapes. During April- August 2011-2014, I examined resource availability, and nest predators, and nest survival of two common birds (American robin, Turdus migratorius and northern cardinal, Cardinalis cardinalis) in seven suburban neighborhoods in the Columbus, Ohio metropolitan area. For the first component of my work, I evaluated demographic differences of robins and cardinals breeding in riparian forest parks and adjacent residential neighborhoods and tested if nest predation was higher in yards. Both robins and cardinals experienced similar nest survival rates in residential yards and forest parks, but there were clear differences in which species were responsible for depredation events. Specifically, domestic cats (Felis catus) were over 5x as frequently documented depredating cardinal nests in yards versus forest parks. For the second component of my work, I tested the hypothesis that wildlife-friendly gardening programs that promote planting trees and shrubs (i.e. increasing woody cover) have the unintended consequence of attracting predators of avian nests by examined relationships between woody cover and diurnal activity patterns of nest predators. Predator activity varied widely among individual yards, but contrary to my hypothesis, the availability of woody cover at either yard or neighborhood scales was not a strong predictor of diurnal activity of five common nest predators. For the third component of my work, I used observational and experimental approaches to investigate how the most common anthropogenic food subsidy, bird feeders, affected predator-prey dynamics in between birds and nest predators in yards. Bird feeders were positively associated with diurnal activity of two nest predators, but the relationship among birdfeeders, nest predators, and nest survival was complex. Nest survival for robins declined with increasing number of bird feeders but only where American crows (Corvus brachyrhynchos) were most frequently detected. For cardinals, nest survival rates showed no association with either feeder availability or predator activity. For the final component of my work, I examined the extent to which nest sites in the residential matrix may offer protection from predation by testing the ability of vegetation characteristics of nest sites and features unique to the urban environment (i.e. roads, buildings, and anthropogenic foods) to predict nest survival. I found that nest site characteristics failed to predict nest survival for cardinals and height was the only significant predictor of robin nest survival. I suggest that the lack of relationship between nest site characteristics and nest fate stem from a diverse predator community that effectively precludes any nest site from being predictably safe for birds breeding in the suburban matrix.

Committee:

Stephen Matthews (Advisor); Amanda Rodewald (Advisor); Stanley Gehrt (Committee Member); Jeremy Bruskotter (Committee Member)

Subjects:

Ecology; Environmental Science; Wildlife Conservation; Wildlife Management

Keywords:

urban ecology; nesting success; predator-prey dynamics; species interactions; anthropogenic resources; subsidies; suburban; nest predators

Smiley-Walters, Sarah AnnInteractions between Pigmy Rattlesnakes (Sistrurus miliarius) and a Suite of Prey Species: A Study of Prey Behavior and Variable Venom Toxicity
Doctor of Philosophy, The Ohio State University, 2017, Evolution, Ecology and Organismal Biology
Interactions between predators and prey are widespread in nature but the ecological and evolutionary factors that shape these interactions are poorly understood. In my dissertation, I use pigmy rattlesnakes (Sistrurus miliarius) and their prey as a system in which to examine several aspects of this species interaction where different ecological and evolutionary factors may be shaping variation in adaptive traits. In Chapter 1, I review factors affecting predator-prey interactions and explain why the pigmy rattlesnake system is valuable for addressing important research questions. In Chapter 2, I present research on the behavioral component of this interaction, demonstrating that native cotton mice do not change their foraging behavior in the presence of a sit-and-wait rattlesnake predator. In Chapter 3, I explore the toxicity of venom to native prey versus non-native "models" to determine to what extent non-native species are representative of prey in the same broad taxonomic group. I show that native prey have higher resistance to venom than non-natives and encourage the use of native prey in future toxicity work. In Chapter 4, I use native treefrog prey from two different populations in Florida and venom from snakes in the same populations to see if there is a signal of local adaptation present in these populations. I show that detection of a signal of local adaptation depends on the measure of venom function used: evidence for local adaptation was observed in the time to death measure of mortality but not in the 24 hour mortality measure. In Chapter 5, I look at the function of venom at a smaller scale by exploring the amount of functional variation present across and within populations of snakes using a lizard model prey. I found the individual component of venom toxicity to be larger than the population-level differences that have been the focus of previous research. Overall, this dissertation demonstrates that rattlesnake venom function differs at both the individual and population scale and that toxicity is relative, depending on the specific prey species tested.

Committee:

H. Lisle Gibbs, Ph.D. (Advisor); Ian Hamilton, Ph.D. (Committee Member); Thomas Hetherington, Ph.D. (Committee Member); Stuart Ludsin, Ph.D. (Committee Member)

Subjects:

Animals; Behavioral Sciences; Biology; Ecology; Evolution and Development; Toxicology; Zoology

Keywords:

predator-prey; venomous snakes; LD50; Peromyscus gossypinus; Hyla squirella; Anolis sagrei; adaptive traits; local adaptation; giving-up density; rodent foraging; individual variation

Marcello, Gregory JamesThe Effects of Predation and Supplemental Food on Foraging and Abundance of White-Footed Mice (Peromyscus Leucopus) in Relation to Forest Patch Size
Master of Science, Miami University, 2005, Zoology
The purpose of this study was to examine some of the possible causes for the negative density-area relationship reported for the white-footed mouse, Peromyscus leucopus. I examined predation and food availability in three small and three large forest fragments. Giving up density trays and various odors were used to test the variation in foraging behavior in the presence of a predator odor. Nest boxes and counts of periodical cicada emergence holes were used to test the effects of an emergence of periodical cicadas on P. leucopus population densities. Predator odors had no effect on foraging behaviors. P. leucopus responded to indirect, but not direct, cues of predation. Estimated densities of periodical cicada emergence holes were strongly related to the relative population density of P. leucopus. Continued study of predation and food differences in forest fragments of different sizes is needed to further examine the negative density-area relationship of P. leucopus.

Committee:

Douglas Meikle (Advisor)

Keywords:

Peromyscus leucopus; periodical cicada; supplemental food; predator odor; giving-up density; patch size; fragmentation