Anthropogenic landscape changes threaten our ecologically and economically critical honey bees by decreasing the availability of quality foraging resources. Importantly, waggle dance analysis provides a versatile and relatively cost-effective tool for investigating the obstacles that honey bees face, such as habitat loss, in our changing landscapes. While this emerging tool has improved our understanding of honey bee foraging in specific landscape contexts, additional research is needed to identify broad trends that span across landscapes. For this dissertation, I used waggle dance decoding and analysis to investigate honey bee foraging, and sublethal stress responses, across three ecologically distinct landscapes in Virginia. In Chapter 1, I introduce waggle dances as a model study system for investigating honey bee foraging and sublethal stress responses by summarizing modern methodological advances in its analysis and emerging research gaps. In Chapter 2, I tested the effects of sublethal imidacloprid exposure on honey bee foraging and recruitment using a semi-field feeder experiment. In doing so, I report that honey bees decreased their foraging, but not recruitment, to an imidacloprid-laced sucrose solution, compared to a control solution. Together, these effects could potentially harm honey bee health by increasing their exposure to pesticides and decreasing their food intake. In Chapter 3, I compared the foraging distances communicated by waggle dancing nectar and pollen foragers across landscapes to explore the economic forces driving foraging to these resources. I observed higher overall and monthly nectar foraging distances compared to pollen foraging distances. Such results suggest that nectar foraging cost dynamics are driven by supply, while pollen foraging cost dynamics are driven by demand. In Chapter 4, I used waggle dance decoding to map and quantify foraging to agricultural grasslands in a mixed-use landscape. In doing so, I demonstrate that honey bees recruit to agricultural grasslands throughout the season, but that this land type was not more attractive than the broader landscape after correcting for foraging distance, which is a relevant cost that flying bees must consider. Additionally, I qualitatively observe a foraging hot spot, representing high honey bee interest, over a highly heterogenous section of the landscape. The collective results of this chapter identify agricultural grasslands as a potential management target and support the importance of landscape heterogeneity to honey bees/pollinators. In Chapter 5, I used waggle dance decoding to investigate honey bee foraging spatial patterns in the context of optimal foraging theory. In particular, I explore whether co-localized honey bee colonies forage optimally by converging on the same resource patches, or by partitioning the landscape in to distinct foraging territories. Spatial analysis revealed that the colonies widely distributed their foraging at the landscape-scale, with dances from the same and different colonies being similarly distributed, while also establishing distinct, patch-scale, colony-specific, foraging aggregations. Together, these results suggest that the honey bee foraging system produces an emergent foraging pattern that may decrease both within- and among-colony foraging competition. Finally, in Chapter 6, I place my research findings in the context of historical and current trends in honey bee behavioral ecology. Overall, my dissertation improves our understanding of honey bee foraging ecology across landscape contexts using waggle dance analysis, while demonstrating its versatility and effectiveness as a tool for ecologists. / Doctor of Philosophy / Honey bees collect nectar (carbohydrate source) and pollen (protein source) from flowers as their food for survival and reproduction. Human activities, such urbanization, change landscapes and threaten our critically important honey bees by decreasing the availability of flower-rich habitats. Importantly, honey bees share the location of good food sources with their nest mates using a communication behavior called the waggle dance. Interestingly, scientists can estimate the approximate location of the food sources communicated by waggle dancing bees through close observation and cutting-edge analysis. Therefore, we can "decode" honey bees' waggle dances to map their food collection, or foraging, patterns and investigate the obstacles that they face in our changing landscapes. For this dissertation, I used waggle dance decoding and analysis to investigate honey bee foraging across three different landscapes in Virginia. In Chapter 1, I introduce waggle dances as a tool for investigating honey bee behavior by summarizing the modern improvements in its analysis and areas where research is needed. In Chapter 2, I tested the effects of a sublethal exposure to a pesticide, imidacloprid, by observing the foraging and waggle dance behavior of bees visiting feeders with artificial food. I report that honey bees decreased their foraging, but not recruitment, while collecting an imidacloprid-laced sugar solution, compared to a solution without imidacloprid. In Chapter 3, I compared the foraging distances communicated by waggle dancing nectar and pollen foragers across landscapes to explore the economic forces driving foraging to these resources. I observed higher overall and monthly nectar foraging distances compared to pollen foraging distances. Such results suggest that nectar foraging is driven by supply, while pollen foraging is more driven by demand. In Chapter 4, I used waggle dance decoding to map and quantify foraging to agricultural grasslands (pastures and hay fields) in a landscape characterized by diverse land uses. In doing so, I demonstrate that honey bees recruit to agricultural grasslands throughout the season, but that this land type was not more attractive than the broader landscape after correcting for foraging distance. Additionally, I qualitatively observe a foraging hot spot, representing high honey bee interest, over a highly heterogenous section of the landscape. The collective results of this chapter identify agricultural grasslands as a potential management target and support the importance of landscape heterogeneity to honey bees/pollinators. In Chapter 5, I used waggle dance decoding to investigate the spatial patterns of honey bee foraging in the context of optimal foraging theory, which attempts to explain efficient resource collection strategies. In particular, I explore whether neighboring honey bee colonies forage optimally by converging on the same resource patches, or by dividing the landscape in to distinct foraging territories. We found that colonies distributed their foraging widely at the landscape-scale, with dances locations from the same and different colonies being similarly distributed, while also establishing distinct, patch-scale, colony-specific, foraging areas. Together, these results suggest that honey bees use a foraging strategy that decreases both within- and among-colony foraging competition. Finally, in Chapter 6, I place my research findings in the context of historical and current trends in honey bee behavioral ecology. Overall, my dissertation uses waggle dance analysis to improve our understanding of honey bee foraging behavior, while demonstrating its versatility and effectiveness as a tool for ecologists.

No description available.

Bumble bees (bombus spp.) are significant pollinators of many plants, and are particularly attracted to mass-flowering crops such as Oilseed Rape (Brassica Napus), which they cross-pollinate. B. napus is both wind and insect-pollinated, and whilst it has been found that wind is its most significant pollen vector, the influence of bumble bee pollination could be non-trivial when bee densities are large. Therefore, the assessment of pollinator-mediated cross-pollination events could be important when considering containment strategies of genetically modified (GM) crops, such as GM varieties of B. napus, but requires a landscape-scale understanding of pollinator movements, which is currently unknown for bumble bees. I developed an in silico model, entitled HARVEST, which simulates the foraging and consequential inter-patch movements of bumble bees. The model is based on principles from Reinforcement Learning and Individual Based Modelling, and uses a Linear Operator Learning Rule to guide agent learning. The model incoproates one or more agents, or bees, that learn by ‘trial-and-error’, with a gradual preference shown for patch choice actions that provide increased rewards. To validate the model, I verified its ability to replicate certain iconic patterns of bee-mediated gene flow, and assessed its accuracy in predicting the flower visits and inter-patch movement frequencies of real bees in a small-scale system. The model successfully replicated the iconic patterns, but failed to accurately predict outputs from the real system. It did, however, qualitatively replicate the high levels of inter-patch traffic found in the real small-scale system, and its quantitative discrepancies could likely be explained by inaccurate parameterisations. I also found that HARVEST bees are extremely efficient foragers, which agrees with evidence of powerful learning capabilities and risk-aversion in real bumble bees. When applying the model to the landscape-scale, HARVEST predicts that overall levels of bee-mediated gene flow are extremely low. Nonetheless, I identified an effective containment strategy in which a ‘shield’ comprised of sacrificed crops is placed between GM and conventional crop populations. This strategy could be useful for scenarios in which the tolerance for GM seed set is exceptionally low.

Whether species interactions are static or change over time has wide-reaching ecological and evolutionary consequences. However, species interaction networks are typically constructed from temporally aggregated interaction data, thereby implicitly assuming that interactions are fixed. This approach has advanced our understanding of communities, but it obscures the timescale at which interactions form (or dissolve) and the drivers and consequences of such dynamics. We address this knowledge gap by quantifying the within-season turnover of plant-pollinator interactions from weekly censuses across 3years in a subalpine ecosystem. Week-to-week turnover of interactions (1) was high, (2) followed a consistent seasonal progression in all years of study and (3) was dominated by interaction rewiring (the reassembly of interactions among species). Simulation models revealed that species' phenologies and relative abundances constrained both total interaction turnover and rewiring. Our findings reveal the diversity of species interactions that may be missed when the temporal dynamics of networks are ignored.

Optimal Foraging Theory (OFT) has its origin in processualistic ideas in 1960s with traces back to the dawn of the archaeological science in the 19th century. The OFT model is based on the construction of an individual’s food item selection understood as an evolutionary construct that maximizes the net energy gained per unit feeding time. The most common variants are diet patch choice, diet breadth/prey choice models and Marginal Value Theorem (MVT). The theory introduced experimental studies combined with mathematically data analyses and computer simulations. The results visualized in the experimental diagrammed curve are possible to compare with the archaeological records. What is “optimal” is an empirical question not possible to know but still useful as a benchmark for measuring culture. The theory is common in USA but still not in Europe. OFT seems to be useful in hunter-gatherer research looking at human decisions, energy flow, depression of resources and extinction. This literature review concludes that the prey-choice/diet-breadth model seems to be useful for hunter-gatherer research on Gotland focusing on possible causes of the hiatus in archaeological records between 5000-4500 BC. / Optimal Foraging Theory (OFT) har sitt ursprung i de processualistiska ideérna under 1960-talet med spår tillbaka till arkeologins början som vetenskap under 1800-talet. OFT modellen baseras på konstruktionen av en individs födoämnesval som förstås som en evolutionär konstruktion som maximerar nettoenergiintaget per tidsenhet som gått åt för försörjningen. De vanligaste varianterna är patch-choice, diet breadth/prey choice modellerna och Marginal Value Theorem (MVT). Experimentella studier genomförs och data bearbetas matematiskt och visar datorsimulerade kurvdiagram möjliga att jämföra med arkeologiska källmaterial. Vad som är ”optimalt” är en empirisk fråga omöjlig att veta men användbar ändå som en slag referens för att mäta kultur. Teorin är vanlig i USA men ännu inte i Europa. OFT förefaller användbar inom forskning av jägare-samlare om man fokuserar på beslutsfattande, energiflöde, depression av resurser och utrotning av arter. Slutsatsen i denna litteraturöversikt är att prey choice/diet breadth modellen tycks vara användbar för gotländsk jägare-samlare-forskning som fokuserar på möjliga orsaker till de arkeologiska fyndens hiatus mellan 5000-4500 BC.

This dissertation presents an evaluation of coprolite specimens from the Lower Pecos canyonlands as records of individual dietary decisions. Prior studies of coprolites from this region have greatly expanded our knowledge of Archaic subsistence patterns, but have not taken full advantage of the record of individual dietary decisions recorded in each coprolite specimen. The menu, or dietary combinations, reflected in individual coprolite specimens are assessed through the identification of several congruent botanical components derived from the same food resource, phytoliths, fiber ultimates, and epidermal sheets. The data is analyzed with hierarchical cluster analysis, an exploratory statistical technique. The resultant menus reflected in these clusters are evaluated with reference to the diet-breadth model developed for the known staple resources of the canyonlands as well as the seasonal subsistence patterns observed in the ethnohistoric record of modern-day Mexico and Texas. This same technique is also applied to the coprolite data available from previous studies in the Lower Pecos canyonlands. Overall, the combined dietary data available for the Lower Pecos canyonlands presents a similar dependence on desertic plant resources throughout the Archaic. Three main menus are apparent in the specimens. The first menu consists of prickly pear (Opuntia sp.) cladodes, or nopales, and was principally, although not exclusively, consumed in the late spring. This menu is primarily consumed when other resources were not readily available and may be considered a dependable but undesirable meal. The second menu consists of pit-baked lechuguilla (Agave lechuguilla) and sotol (Dasylirion sp.) caudices, or hearts, common throughout the cool season. This menu entails high processing costs, but would provide a reliable caloric return. The third menu exhibits a monolithic reliance on prickly pear fruits, or tunas, during the summer. The ease of harvest and consumption is reflected in the seasonal dominance of this resource, which was assuredly a highly desirable meal. The dietary patterns recorded in the coprolite specimens from the Lower Pecos canyonlands demonstrate a seasonally variable diet-breadth that incorporated low-ranked resources during times of seasonal scarcity as well as a monolithic dependence on high-ranked resources when they were available in the local landscape.

The Optimal Foraging Theory, rooted in the processual archaeology, uses a measuring methodology where the foraging strategy that gives the highest payoff measured as the highest ratio of energy gain per time unit is analysed (Mac Arthur & Pianca 1966, Emlen 1966). The theory is a branch of evolutionary ecology why much attention is paid to the interdependence of humans and preys and environmental conditions caused by climatologically and geographical changes or by overexploitation or other changes caused by humans. The analysis of Early Mesolithic pioneers onGotland, who settle in a transforming landscape, leaves indications of a Maglemose culture origin, probably from flooded original settlements in the south/southwest Baltic basin. The pioneers have to adapt to a seal-hunting economy dominated by grey seal which give the best cost-benefit outcome as big terrestrial mammals are missing and only mountain hare is available. The diet is narrow and there is a great risk for deficiency diseases as well as for acquiring hypervitaminosis and osteoporosis caused by excess of seal food. There is a hiatus c. 5000-4500 BC in the archaeological records on Gotland and the south-western Baltic region, and the master thesis hypothesises that Littorina Transgression I with a severe cold dip called the “8.2 ka BP cold event” has a delayed, but such a severe impact also on fauna and flora on Gotland, that the ecological system is destroyed. The possibility for humans to survive in a sustainable society is questionable. The extremely cold winters during this c. 400 years cold event, with glaciers moving southwards, delayed the blooming season, diminished the harvest and changed both flora and fauna. When the ecological niche for the grey seal is destroyed with flooded beaches close to the pioneers, human overexploitation is reinforced. With a diminishing population of mountain hare, which eventually gets extinct at the end of the Mesolithic, there are no alternatives but some birds and fish, hard to catch. Probably the pioneers abandon Gotland or move to a higher level on Gotland but no records are yet found why the period is called a hiatus. Extinction is the worst scenario or survival in such a small number that a sustainable society is lost. If so, new population groups repopulatedGotlandafter the Littorina transgressions. The origin is still unknown of the Pitted-ware and Funnelbeaker cultures that are populating Gotland after the transgressions. This master thesis can not confirm an affluent life style but rather a suffering starving society flooded by Littorina transgressions and struggling with the severe cold, caused by the “8.2 ka cold event” that makes the environmental conditions even worse. The subsistence economy is successively destroyed which probably causes the hiatus in archaeological records. The Littorina Transgression I with the “8.2 cold event” and the lack of terrestrial big animals are bottle necks. / Optimal Foraging Theory, med sina rötter i den processuella arkeologin, använder en metodik utgående från mätningar där insamlingsstrategin som ger den högsta avkastningen per tidsenhet analyseras (Mac Arthur & Pianca 1966, Emlen 1966). Teorin är en undergrupp inom den evolutionära ekologin och därför ägnas stor tid åt att uppmärksamma det ömsesidiga beroendet och påverkan som sker i miljön p.g.a. klimatologiska och geologiska orsaker men också p.g.a. mänsklig påverkan som exempelvis överförbrukning.  Analysen av tidigmesolitiska pionjärbosättare på Gotland, som möter ett landskap i förvandling, lämnar spår efter sig som tyder på ett ursprung i Maglemosekulturen i södra/sydvästra Östersjöregionen. De tvingas bli adapterade till en säljägarekonomi dominerad av gråsäl som ger det bästa energiutbytet, eftersom stora landdäggdjur saknas och endast bergshare finns tillgänglig. Dietvalet är smalt och det föreligger stor risk för både bristsjukdomar och A-vitaminförgiftning och osteoporos p.g.a. överkonsumtion av sälprodukter. Det finns ett uppehåll i de arkeologiska fynden c. 5000-4500 BC på Gotland liksom i södra Östersjöområdet. Magisteruppsatsens hypotes är att den kalla perioden med temperatursänkning som kallas ”8.2 ka BP cold event” under Littorinatransgression I har en fördröjd men så kraftigt övergripande effekt, på både djur- och växtliv på Gotland, att den förstör det ekologiska systemet och därmed möjligheten för människor att överleva i ett hållbart samhälle. De mycket hårda vintrarna under de c. 400 årens ”cold event” medför att glaciärerna dras sig söderut, blomningssäsongen fördröjs, skörden minskar och både fauna och flora förändras. När den ekologiska nischen för gråsälen förstörs av översvämmade stränder nära bosättarna förstärks överexploateringen, och då det inte finns någon alternativ föda utom en minskande harstam, svårfångade fåglar och fiskar, blir situationen fatal för de tidigmesolitiska bosättarna. Troligtvis flyttar de till andra platser inom Östersjönätverket eller till en högre nivå på Gotland, men fynd saknas hittills varför detta tomrum benämns ”hiatus”. Det värsta scenariot är att bosättarna dör ut eller överlever i ett så litet antal att det hållbara samhället går under.Om så är fallet återbefokas Gotland av gropkeramisk kultur och trattbägarkultur i anslutning till Littorinatrasgressionernas slut. Denna magisteruppsats kan inte konfirmera en livsstil i överflöd, utan snarare ett lidande svältande samhälle som översvämmas av Littorinatransgressioner med miljömässiga förhållanden som förvärras av den allvarliga kylan orsakad av ”8.2 ka cold event”.  Försörjningsmöjligheterna förstörs succesivt och befolkningen försvinner vilket troligen orsakar ett hiatus i de arkeologiska fynden. Littorina Transgression I med ”8.2 ka cold event” och bristen på stora landdjur är stora flaskhalsar.

Coral reefs are one of the world’s most diverse yet heavily impacted marine ecosystems. As a result of many direct and indirect stressors, coral reefs have experienced major degradation over the last several decades. Declines in coral reefs in the Caribbean have been particularly acute and generally associated with the loss of key herbivores and an increase in algae. Herbivorous fishes such as parrotfishes can positively impact coral reefs by removing algae that compete with corals for light and space. However, many parrotfishes are also important coral predators. Predation on corals, known as corallivory, can adversely affect coral growth, reproduction and survivorship. In this time of changing environments and coral reef decline, understanding the context-dependent nature of parrotfish foraging behavior is of critical importance to scientists and managers. Knowledge of the responses of parrotfishes across a range of resource abundance will help scientists and managers better predict the impacts that these herbivores have on benthic communities as both herbivores and corallivores. In Chapter 1, we examined how six different species of coral reef herbivores (i.e. parrotfishes), all of which belong to a single feeding guild but represent a range of dietary specialization, respond to changes in the abundance of preferred food items. We conducted behavioral observations of parrotfishes in two regions of the Greater Caribbean, and compared consumption rates, diet preferences, and foraging territory size in relation to natural variation across sites in preferred resource abundance. We found that the more-specialized parrotfishes increased their dietary specialization, had smaller foraging territories, and increased their feeding rate with increased preferred resource abundance. In contrast, less-specialized species exhibited constant foraging traits regardless of the abundance of their preferred resources. This study suggests that differences in dietary preference, specialization, and subsequent nutritional demand may drive a differential response in foraging behavior by generalists and specialist herbivores to changes in resource abundance. Recognizing that generalists and specialists differ in the degree to which their foraging behaviors are context-dependent can allow researchers to better predict how herbivores shape the structure and function of marine and terrestrial ecosystems. In Chapter 2, we determined if and how corallivory rates and intensity by parrotfishes differ between two regions of the Greater Caribbean that vary in coral and parrotfish community composition and abundance. We found that more species of parrotfishes than previous studies suggest contribute to corallivory. However, corallivory rates and selectivity for coral species by parrotfishes were largely context-dependent, particularly with regards to the relative abundance of preferred corals and diversity of corallivores at a given site. Although we found that corallivory rates decrease with coral cover, it appears that areas of low coral cover may have high corallivory intensity and coral tissue loss, in part due to the relatively high abundance of corallivores in these areas. The impact of high corallivory intensity and tissue loss requires further knowledge regarding the fate of bite scars on corals.This information will help predict the positive and negative consequences of parrotfishes on coral persistence in the Caribbean. Evidence provided in this thesis furthers our understanding of the dual role of parrotfishes as herbivores and corallivores. Additionally, it reveals the implications of changing coral reef habitats on parrotfish behavior and subsequent coral reef health and resilience.

No description available.

The main purpose of this dissertation is to assess ontological issues of information acquisition, focusing on information overload from an integrative perspective of two theoretical foundations, which links two perspectives of consumer behavior in information acquisition: foraging theory in behavioral ecology and information processing theory in marketing. Applying to the integrative investigation, the current research primarily emphasizes the infusion of ecological rationality (i.e., Darwinian Theory) into normative rationality (i.e., Newtonian Theory), but it is not alternative but complementary to each other. Ecological rationality, which is rooted in Darwinism, emphasizes that human behavior has developed through adaptation and natural selection as the human minds interact with environments. The current study consists of five chapters: the philosophical foundation of the rationalities, exploratory study, proposed hypotheses, empirical tests, and general discussion. A summary of the contents of each chapter is: The first chapter aims to provide an integrative framework of consumer information acquisition in order to explore ontological issues in information overload paradigm, attempting to synthesize different approaches in marketing and behavioral ecology. To explore, the current study emphasizes an integrative perspective between two theories for information acquisition (foraging and information processing), which are based on different philosophical foundations of the rationality (ecological and normative). Along with the process of the information acquisition, this study provides relevant consequences (decision-related responses and decision-related alternatives) after the information acquisition process and influential factors in temporal and psychological dimensions (time and motivation). Then, the conceptual study provides conclusion and the current research scope. The second chapter aims to examine the efficacy of the current study's theoretical integration in the process of consumer information foraging so as to approach an ontological issue in information overload paradigm: more information is better vs. less information is better (i.e., information processing theory and foraging theory under an information overload paradigm). Therefore, this study explores and examines what can be appropriate information structures to describe the ontological issue in the process of consumer information foraging. To formulate the adequate information structure, this study attempts to utilize an integrative perspective between marketing and behavioral ecology. This study examines consumers' online activities sequentially from a broad to detail approach, based on the categories of goods and services. The result, by and large, suggests a necessity of an integrative perspective to view a holistic information structure, including quantity, quality, and environment components. These structural components interactively communicate with minds when shaping the process of the consumer information foraging, which are likely to involve in the degree of information overload. Moreover, results demonstrate rather higher variation of strategic information foraging but emphasize some important communality in the initial stage of information foraging, such as the role of search engine and interpersonal communication. In addition, categories of goods and services affect shaping the pattern of strategic information foraging. Then, the conclusion of the study provides. The third chapter aims to propose a hypothetical model, based on the theoretical backgrounds in Chapter 1 and the findings of the exploratory study in Chapter 2. In addition, the pilot study was conducted to provide a concrete framework of the empirical study by checking the manipulation of holistic information structures. The manipulation of the structures includes the total quantity of information, the quality of information, and environmental information. Those structures measured on several resultant consequences, using the patch concepts (within-patch and between-patch). Controversially, in general, consumers tend to prefer more information rather than less information only when arranged information provides; otherwise, this preference attenuates. This controversial result also has conflicting variations, depending on the types of patches. Overall, the comparison in the within-patch and between-patch through displaying heterogeneous information structures suggests that holistic information structures are a more important factor than the mere quantity or quality of information. The fourth chapter empirically tests the theory-based hypothetical frameworks to assess the ontological issues in information overload paradigm using the integrative perspective of the two information acquisition theories. The findings of the empirical study suggest that the real-world information overload is not simply determined by a single dominant factor (e.g., quantity), but by the interplay of intricately intertwined factors. The factors are the following: information structures (three unarranged and four arranged information structures, including quantity, quality and environment), item categories (durables, nondurables and services), and time constraints (time pressure vs. no time pressure). The interwoven complexity implies that paradigmatic change of perspectives in relation with information overload though integrating two important conceptual factors between domain-specific dependency and universality. Moreover, the information overload begins with the browsing stage of acquiring the necessary information, not with the searching stage, suggesting the view of browsing-searching continuum that underscores the important role of the patch concept. As a whole, the conclusive findings suggest an integrative perspective between Darwinism and Non-Darwinism as a prerequisite of providing a better comprehension of the issues of the information overload paradigm. The fifth chapter is the section of general discussion including major findings, theoretical, methodological and empirical implications, limitations, and conclusive statement. / Business Administration/Marketing