Doctor of Philosophy / Department of Entomology / David C. Margolies / James R. Nechols / Foraging traits such as prey consumption rate and the efficiency with which predators convert their prey into offspring are important determinants of local predator-prey dynamics. However, in environments with patchy prey distribution, predator dispersal and aggregation in response to prey-induced volatile cues becomes more critical. My dissertation addressed predator-prey population dynamics in response to variation in four foraging traits in the predatory mite, Phytoseiulus persimilis (Acari: Phytoseiidae): consumption rate, conversion efficiency, dispersal, and olfactory response related to prey. The dispersal response and olfactory sensitivity in predatory mites is modified by prey-related cues. For example, the dispersal response increased with decreasing prey density in a patch and increasing prey-related volatiles from outside the prey patch. The olfactory response of predatory mites also increased with increasing numbers of prey per plant or with the length of time a plant was infested by prey. These results formed the basis for development of bioassays used to examine genetic variation in dispersal and olfactory response of predatory mites. Through artificial selection I documented additive genetic variation in all four traits. After relaxation of selection, high-level phenotypes were stable compared to their low counterparts. There were significant genetic correlations between some of the foraging traits. However, there were no correlations between foraging traits and life-history traits. The existence of genetic variation and covariation among the foraging traits suggests that predatory mites must be able to adopt different foraging strategies in the evolution of prey-finding in a tritrophic system. High consumption, high conversion efficiency and high dispersal response phenotypes interacted differently with prey in a spatially complex landscape. All foraging traits were comparable in terms of predator-prey densities and plant damage; but they were lower than the unselected control. Spatial association and correlation analysis showed that all foraging traits were positively associated with prey; but the strongest association was observed for the high conversion efficiency and dispersal lines. The variability in foraging behaviors of the predatory mite affects its ability to locate patchily distributed prey, thereby influencing foraging efficiency and population dynamics. This research provides new information about the critical link between predator foraging and population dynamics relevant to biological control.

Polar desert environments are limiting in plant available nutrients, mainly nitrogen (N) and phosphorus (P) that severely limit plant growth and establishment. Cryogenic activity regularly patterns the ground into a patchwork of frost boils – sorted circles that are associated with an increase in moisture, fertility and plant cover. Within some frost boils, the accumulation of ice-rich soil at the permafrost table can cause an upward flow of soil organic carbon (SOC) enriched permafrost material into the active layer. These diapiric intrusions are predicted to fuel microbial activity and enrich the horizon in N and P; however, the enrichment of the diapir horizon and accessibility by plants has yet to be studied. The aim of this research was to characterize the N distribution within diapir horizons located in frost boils and the effect of these intrusions on vascular plant N uptake in a polar desert ecosystem of the Canadian High Arctic. Natural abundance and enriched isotope 15N techniques were used to trace the flow of N through the soil-plant system. Surface and diapir horizons contained the highest total C and total N content within frost boils. Natural abundance δ15N analysis indicated that uptake by Salix arctica plants located on frost boils in the absence of a diapir horizon were sourcing N from the surface. However, when diapir nutrients became available, S. arctica plants began sourcing N from the diapir horizon and underlying low SOC sources in the soil, while reducing uptake from the surface. The altered foraging strategy of S. arctica in response to diapir horizon formation was further indicated by significant uptake of atom%15N nutrients that were injected directly into diapir horizons. These findings suggest diapir horizons are enriched in N and accessible by plants roots as an important nutrient source that is instrumental in their survival within frost boils of a polar desert ecosystem in the high arctic.

The following thesis presents the results of a mixed-design study (quasi-experimental and true experimental) testing an integrated model of human risk-taking behavior, defined statistically as a preference for variance in outcomes. The research presented examines the relationships among early-life environmental conditions (i.e., harshness and unpredictability), life-history strategy, and risk-taking behavior for primary resources under various "resource-budget" conditions consisting of deprivation and non-deprivation in two areas: (1) Social-inclusion and (2) caloric "Energy-budget." Two hundred and forty seven (N=247) university students participated in the research. In session one, participants completed multiple questionnaires assessing levels of environmental harshness and unpredictability experienced during development and individual life-history strategy. In session two, participants were pseudo-randomly assigned to experience laboratory induced deprivation or non-deprivation in one of two possible areas: Social-inclusion or caloric "Energy-budget." Following the experimental manipulations, participants played two different behavioral risk-taking tasks: (1) The Wheel Spin Risk Task which required participants to select between a low variance "safe" wheel and a high variance "risky" wheel in an attempt to earn either points or food rewards (depending upon study condition). (2) The Operant Risk Taking Task which required participants to select between a low variance "safe" keyboard key which produced constant rewards and a high variance "risky" keyboard key which produced variable rewards (points or food, depending upon study condition). The results of the multivariate analyses supported main effects only (no moderation) between the characteristics of the early-life environment, life-history strategy, and the experimental manipulations on risk-taking behavior. Specifically, early-life harshness was significantly associated with a faster life-history strategy in participants. Participants with a faster life-history strategy were significantly more likely to select the risky spin wheel on the Wheel Spin Risk Task than were slower life-history strategy participants who were more likely to select the safe spin wheel. Furthermore, participants who experienced the deprivation experimental manipulations behaved more risky on the Operant Risk-Taking Task (for reward amount) than did participants exposed to the non-deprivation manipulations in the study. Interestingly, this effect was domain-general in that deprivation in either Social-inclusion or Energy-budget was associated with risk taking for both social points and for food rewards. The results of this study suggest that life-history strategy is predictive of instrumental risk-taking behavior for reward amount and that deprivation in adaptive areas like Social-inclusion and Energy-budget enhances risk-taking behavior for primary rewards in a domain-general manner as opposed to a domain-specific manner.

Natural enemies are members of complex ecological communities, and their ability to contribute to the biological control of pest organisms is strongly influenced by a convoluted network of ecological interactions with many other organisms within these communities. Researchers must develop an understanding of the mechanisms that shape trophic webs to predict and promote top-down effects of predators. The behavior of predators can have a strong influence on their potential as biological control agents. Web-building spiders are a useful example organism for the study of natural enemy behavior because of the experimentally tractable nature of their foraging behavior. Specifically, patterns in microhabitat utilization and web construction by spiders provide insights into foraging behavior and pest-suppression potential. In field collections, spiders were found to utilize microhabitats in a species-specific manner. Molecular gut-content analysis and a mathematical model showed that two spiders belonging to different web-building guilds differed in their dependence on microhabitat-specific prey activity-densities. In particular, the sheet-weaving guild constructed webs in microhabitats with the highest densities of springtails (Collembola). High dependence on this non-pest prey also correlated with evidence of increased intraspecific competition, and implies a potential negative effect of springtails on the consumption of pest insects, such as aphids. In laboratory two-choice assays, sheet-weaving spiders selected microhabitats and constructed webs in a flexible, stepwise manner, which allowed spiders to regulate their investment of silk resources to match the profitability of the microhabitat. Spiders also exhibited prey-specific shifts in foraging behavior, constructing webs in the presence of mobile, non-pest springtails, but utilizing active foraging tactics in the presence of sedentary, pest aphids. However, in factorial no-choice assays, pest-consumption rates were not significantly affected by the presence of non-pest springtails, indicating that prey-specific foraging-mode shifts are compatible with biological control. From these results, it is clear that the flexible foraging behavior of web-building spiders has a strong influence on their roles in ecological communities and their position within food webs. This dissertation highlights the importance of understanding the nuances of natural-enemy behavior for properly assessing and promoting biological control services.

<p>Företag som bedriver handel via nätet på sajter som inriktar sig mot privatpersoner satsar idag mycket på att utvecklas för att på bästa sätt stödja kunden mot sitt mål. Dock har företag som inriktar sig mot andra företag (B2B-business to business) inte hängt med i samma utsträckning. Den här rapporten syftade till att undersöka hur man kan arbeta för att ta fram ett designförslag på en B2B-sajt, närmare bestämt vilka metoder och teorier man kan dra nytta av. Metoder och teorier som har använts är effektkartläggning, Coopers målinriktade designmetod, Nielsens designprinciper för användbarhet och information foraging. Arbetet resulterade i en prototyp kring vilken en diskussion fördes följt av slutsatsen att valet av metoder och teorier tycks vara en lämplig kombination vid utveckling av B2B-sajter men att ytterligare forskning krävs för att skapa en enhetlig metod.</p>

An understanding of the spatio-temporal dynamics of marine predator populations is essential for the sustainable management of marine resources. Tagging studies are providing ever more information about the movements and migrations of marine predators and much has been learned about where these predators spend their time. However little is known about their underlying motivations, making it difficult to make predictions about how apex predators will respond to changing environments. While much progress has been made in behavioural ecology through the use of optimality models, in the marine environment the necessary costs and benefits are difficult to quantify making this approach less successful than with terrestrial studies. One aspect of foraging behaviour that has proved tractable however is the optimisation of random searches. Work by statistical physicists has shown that a specialised movement, known as Lévy flight, can optimise the rate of new prey patch encounters when new prey patches are beyond sensory range. The resulting Lévy flight foraging (LFF) hypothesis makes testable predictions about marine predator search behaviour that can be addressed with the theoretical and empirical studies that form the basis of this thesis. Results presented here resolve the controversy surrounding the hypothesis, demonstrating the optimality of Lévy searches under a broader set of conditions than previously considered, including whether observed Lévy patterns are innate or emergent. Empirical studies provide robust evidence for the prevalence of Lévy search patterns in the movements of diverse marine pelagic predators such as sharks, tunas and billfish as well as in the foraging patterns of albatrosses, overturning a previous study. Predictions from the LFF hypothesis concerning fast moving prey are confirmed leading to simulation studies of ambush predator’s activity patterns. Movement analysis is then applied to the assessment of by-catch mitigation efforts involving VMS data from long-liners and simulated sharks.

Disturbance from engineering works is an increasing problem in terrestrial and marine ecosystems throughout the world. Many reported declines in population size, breeding success and body condition have been diagnosed as the result of anthropogenic disturbance, however little is known about the effect of long-term disturbance from large-scale engineering works. Understanding the mechanisms by which animals respond to anthropogenic activities is fundamental to explaining interactions, and resolving potential conflicts between humans and wildlife. This thesis focuses on the factors affecting the habitat use and foraging decisions in wintering shorebirds and wildfowl. The first half of this thesis considers the direct and indirect impacts on waterbirds of a major engineering project in central Scotland; construction of the new Clackmannanshire Bridge at Kincardine-on-Forth. For individual bird species in close proximity to the bridge site, round-the-clock construction work had consequences ranging from neutral to considerably negative. Cormorant Phalacrocorax carbo declined in the area, probably as a result of the disturbance of an important low tide roost. Redshank Tringa totanus, previously abundant in the prey-rich areas adjacent to the construction site, were displaced into poorer areas for most of the construction period; where they may also have suffered from increased interference competition and elevated risk from raptorial predators. Some positive effects of industrial development were also revealed; radio-transmitters combined with tilt-switch posture sensors indicate that Redshank were able to capitalise on the improved nocturnal visibility in areas around Grangemouth docks to assist with foraging and predator detection. Evidence is presented that birds switched foraging strategy (from sight to touch feeding) depending on ambient light levels; whereby artificial light was used in a similar manner to moonlight to assist with prey detection. Redshank also avoided riverine areas at night that were used frequently by day, probably in response to an elevated threat from nocturnal predators. As the predator landscape changes from day into night, birds adopt different strategies to minimise the risk from nocturnal predators. It is clearly important, therefore, that information on nocturnal distributions is available to inform decisions on site management, especially where anthropogenic activity continues throughout the diel cycle. Behavioural decisions were shown to vary widely within a species depending on individual state, metabolic demands and previous exposure to human disturbance. Prey resources were shown to change dramatically over the course of a winter. In response to this decline, the home range of Redshank contracted over a winter season. Similarly, animals responded less and took greater risks in response to experimental disturbance events later in the winter than earlier in the winter, and on days when the temperature was lower. This effect was strongest for individuals occupying heavily disturbed areas, which were possibly already compensating for lost feeding time and a negative energy balance. The results were consistent with the hypothesis that those individuals that respond most obviously to human disturbance were those least likely to suffer fitness consequences. This is the opposite from what is commonly assumed when behaviour is used as an index of disturbance impacts, most notably in the use of flush distance in the design of wildlife buffer zones. In conclusion, this study demonstrated various negative impacts of disturbance, including local displacement, due to construction activity on overwintering waterbirds. It also revealed two key, but poorly understood, phenomena relating to mechanisms for coping with anthropogenic disturbance: routine utilisation of artificial light to extend night-time feeding opportunities amongst Redshank and an adaptive flexibility in escape responses across a range of species under varying conditions of risk.

As wild edibles gain in popularity both on restaurant menus and as a form of recreation through their collection, research on contemporary foragers/wildcrafters/gatherers of wild edibles has so increased from varied disciplinary perspectives. Through an exploration of gatherers in Vermont, I examine the relationships between practice and identity. By employing intersectionality through feminist ethnographic methods, this research recognizes the complex intersections of individuals' identities that challenge a more simplified, additive approach to definitions of race, class, gender and the myriad identities that inform one's experience of privilege and oppression. As prior scholarship has established, people from diverse ethnicities, genders, religions, class affiliations, rural and urban livelihoods, and ages gather wild edibles. This thesis draws connections between the intersectional identities of gatherers and the diversity of their gathering practices. This project includes a discussion of how intersectionality may be applied and employed as analytical theory and as methodological foundation to better approach connections between identity and practice. Key questions driving the analysis are: what are the intersectional identities of gatherers of wild edibles in Vermont, and to what extent are these intersectional identities informing, or informed by, harvest and post-harvest practices? This research contributes to scholarship on foragers from a qualitative methodological perspective and attempts to support the body of literature on intersectionality as methodology as well as research that focuses on the connections between people, practice, and wild foods.

A fundamental question in biology is how animals efficiently locate and use diverse resources. Pollinators foraging on flowers are one of our most thoroughly studied examples of generalist foraging behavior and cognition. Individual pollinators typically specialize on a subset of flowering species available to them. Specialization by nectar-foraging pollinators is often the consequence of learned or innate preferences for floral display traits such as color, pattern, and scent. Pollinators must also typically learn to extract nectar from each floral type. By specializing, pollinators reduce costs associated with learning and forgetting nectar extraction routines. Specialization also benefits the plant by enhancing conspecific pollen transfer. Yet nectar is not the only floral reward. The pollen of hundreds of thousands of plant species is collected by pollinators such as bees, beetles, and flies. In fact, solitary and social bees must collect both pollen and nectar to survive. However, much of the vast literature on bee foraging behavior concerns the collection of nectar. This research investigated mechanisms by which generalist bumblebees (Bombus impatiens) specialize on diverse floral resources. Most foragers in a colony were reward generalists over their lifetime, but specialized daily on either pollen or nectar collection. Lifetime patterns of pollen collection were associated with interindividual differences in sensory morphology. Pollen-foraging bumblebees had weak innate preferences, but learned strong preferences for pollen-only plant species, with preferences mediated primarily by anther properties. The anthers provided indirect cues of concealed pollen, and bees learned to prefer properties of the anthers to select potentially rewarding flowers. While learning was involved in the formation of floral preferences by pollen foragers, pollen extraction behavior relied little on learning. Specifically, floral sonication, which is used by bees to extract concealed pollen, was modified only modestly with experience. Furthermore, bees foraged efficiently for pollen from diverse floral resources without relying on instrumental (associative) learning. Efficient foraging involved switching between two distinct motor routines: floral sonication and scrabbling. Switching was regulated by two ubiquitous floral cues: chemical anther cues eliciting sonication and mechanical pollen cues suppressing it (and eliciting scrabbling). I discuss how mechanisms of floral specialization by generalist pollen-foraging bees could drive floral trait evolution.

The aim of this thesis was to understand the function of the frontal lobes during different types of decisions thusfar mostly neglected in cognitive neuroscience. Namely, I sought to understand how decisions are made when comparisons are not about a simple set of concrete options presented, but rather require a comparison with one specific encounter and a sense of the value of the current environment <b>(Chapter 2-3)</b>. Additionally, I wanted to understand how decisions between concrete options can be contextualized by the current environment to allow considerations about changing environmental constraints to factor into the decision making process <b>(Chapter 4-5)</b>. At last, I wanted to test how the potential for future behaviours within an environment has an effect on peoples decisions <b>(Chapter 6)</b>. In other words, how do people construct prospective value when it requires a sense of own future behaviours? All this work was informed by concepts and models originating from optimal foraging theory, which seeks to understand animal behaviours using computational models for different ecological types of choices. Thus, this thesis offers a perspective on the neural mechanisms underlying human decision making capacities that relates them to common problems faced by animals and presumably humans in ecological environments <b>(Chapter 1 and 7)</b>. As optimal foraging theory assumes that solving these problems efficiently is highly relevant for survival, it is possible that neural structures evolved in ways to particularly accommodate for the solution of those problems. Therefore, different prefrontal structures might be dedicated to unique ways of solving ecological kinds of decision problems. My thesis as a whole gives some evidence for such a perspective, as dACC and vmPFC were repeatedly identified as constituting unique systems for evaluation according to different reference frames. Their competition within a wider network of areas appeared to ultimately drive decisions under changing contexts. In the future, a better understanding of those changing interactions between these prefrontal areas which generate more complex and adaptive behaviours, will be crucial for understanding more natural choice behaviours. For this temporally resolved neural measurements as well as causal interference will be essential.