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The Great Plains piping plover (Charadrius melodus) population was listed as threatened under the Endangered Species Act in 1986. The challenge for managers of this population is to increase the fledging rate and to ensure that there is sufficient habitat to support an increasing population. According to the revised recovery plan, there are insufficient quantitative data that relate habitat characteristics to reproductive success in riverine habitat. In particular, additional data are needed to determine if piping plover reproduction is limited by food abundance at breeding sites. The goal of this research was to determine whether piping plover chick survival was limited by foraging site quality on the Missouri River. Productivity has historically varied among river reaches. The alkali wetlands, reported to be very productive, serve as an index to the upper limit of reproductive potential. We compared indices of foraging site quality, chick growth and survival among a reservoir, two river reaches and alkali wetland sites from 2001-2003. We compared piping plover use of protected shoreline and exposed shoreline to availability along two reaches of the Missouri River (Gavins and Garrison). We also examined piping plover chick diet. Chick weight gains were higher at alkali wetlands than Gavins and Garrison. Invertebrate numbers were higher at the alkali wetlands than the three river sites and lowest downstream of the cold water release dam. Invertebrate biomass was highest at the alkali wetlands and downstream of the warm water release dam and lowest downstream of the cold water release dam. Invertebrate biomass downstream of the cold water release dam was the lowest of all 4 sites. There was no relationship between chick daily survival rates and invertebrate biomass or predator presence. Although Diptera occurred more frequently (23% - 64%) at all sites (sticky traps), Coleoptera occurred most frequently in the fecal samples (fecal analysis; 69% to 89%). On the Missouri River, protected shorelines were important foraging sites for piping plovers during the breeding season. We also found that sandbars with low-lying moist habitat are important to foraging chicks. Results are consistent with the prediction that foraging conditions downriver from cold water release dams are inferior to conditions in other habitats in the region. Differences in prey availability are reflected in chick growth rates, but not in survival rates. These results underscore the variability in different indices of habitat quality (invertebrate indices, predation, growth rates, survival rates) among the four sites, and the need for monitoring and management strategies that address each site individually. When managing or creating sandbars, ensuring the availability of protected shoreline will benefit piping plovers on the Missouri River. / Ph. D.

The waggle dance of the honey bee (Apis mellifera L.) is perhaps the most celebrated animal communication behavior. With a waggle dance, a forager bee who has discovered a profitable resource on the landscape, usually floral nectar or pollen, can inform her nestmates of its location and recruit them to exploit it by communicating both a distance and a direction. Since Karl von Frisch described the waggle dance in 1942, scientific exploration of the dance has exploded into the realms of its structure, function, role in the regulation of collective foraging in the context of the hive as a super-organism, and even its utility as a study system for understanding sublethal behavioral effects of pesticide exposure. This dissertation presents three novel studies of the waggle dance. In the first, we asked whether consistent inter-bee differences (i.e., individuality) in a waggle dance distance - duration calibrations could affect communication success. In the second, we characterized the networks of recruitment arising from waggle dance communications and explored the role of the aforementioned individuality in network formation. In the third, we tested whether sublethal exposure to glyphosate (GLY), the most-applied herbicide in the world, could affect foraging, recruitment, or the levels and balance of biogenic amines in the bee brain. In each of these experiments, we housed bees in clear-walled observation colonies and trained cohorts of bees to visit artificial feeders to record both foraging and recruitment data. In our first experiment, we found that individuality in waggle dance behavior does shape communication outcomes, indicating that individual-level behavioral differences should not be discounted as factors at work in eusocial insect societies. In the second, we present the first network density and dance burstiness data from in vivo bee networks, revealing that recruitment networks are sparse, and waggle dancers are partitioned into bursty and non-bursty behavioral types. In the third, we show that not only can sublethal GLY exposure reduce foraging, but it can also produce significant correlations between levels of the important insect neurotransmitter octopamine and its two biosynthetic precursors, tyramine and tyrosine, where levels in control bees were unrelated. The results of this dissertation research, while distinct by experiment, together emphasize the continuing usefulness and tractability of the honey bee colony as a system in which to study the role of individuality in animal communication and to better understand the threat posed by non-insecticidal pesticide chemistries to the planet's most economically impactful pollinator. / Doctor of Philosophy / One of the most famous and well-studied animal behaviors is the waggle dance of the honey bee. A honey bee's waggle dance works similarly to a Yelp review for a restaurant: a bee who has found a good food source, like a flower patch offering especially sweet nectar or high-quality pollen, can come back to the colony and recommend it to her nestmates with a dance. The waggle dance is even more specific than a Yelp review, however, in that it also gives instructions to find the food source, communicating both a distance and a direction so that dance followers can go out into the landscape and look for the food source themselves. Even though the waggle dance has been studied extensively since it was first described by Karl von Frisch in the 1940s, there are still unknowns about how it works, and how it might be impacted by certain stressors. This dissertation presents three different experiments aimed at shedding light on these unknowns. First, it has recently been shown that there are consistent differences between bees in the way they communicate distance in the dance, and we tested whether that between-bee individuality can affect the likelihood that two bees will communicate successfully. Second, we studied how information about a food source moves from bee to bee via the waggle dance to form a communication network. Specifically, we described how efficiently information moved from bee to bee, patterns of dancing behavior, and the role of that individuality in its formation. Third and lastly, we looked to see whether exposure to a weedkiller called glyphosate (GLY) could affect either honey bees' waggle dance or food-collecting behavior, as well as levels of certain neurotransmitters in their brains that are involved in those behaviors. In all three experiments, we collected our data by housing bees in a clear-walled observation hives that let us view and film their waggle dance behavior, and then training groups of bees to collect artificial nectar from a feeder station that we provided, so we could also observe them as they collected food. We found that individuality in waggle dance communication can indeed affect the likelihood of communication success between two given bees, where the likelihood of communication success is greater when the dancer communicates a farther distance to the food source than the follower would. In the second experiment, our study of the waggle dance communication network showed that (1) information does not flow from bee to bee very efficiently, and (2) bees either dance quite regularly or sporadically. As far as we know, we are the first to describe these aspects of the waggle dance communication network, which may be useful in the field of computing algorithms inspired by living organisms. Finally, our third experiment showed that mild GLY exposure not only reduced how frequently bees collected food from our feeder, but also changed the relative amounts of certain neurotransmitters in their brains. This result emphasizes the importance of understanding how weedkillers that are not meant to target beneficial insects like honey bees are actually affecting them, so that we can make better-informed decisions to protect honey bees and other good insects.

The ability to forage successfully is intimately tied to juvenile survivorship in many avian species. The time it takes juveniles to develop competent foraging skills varies with the prey type and foraging behaviors. My research examined the length of time it took juvenile Black Phoebes (Sayornis nigricans), a bird species abundant in urban environments, to exhibit foraging behavior similar to adults. Black phoebes are insectivorous and forage by scanning for and then pursuing potential prey. I hypothesized that before they disperse, approximately two months after fledging, juvenile phoebes should forage as successfully as adults. Because foraging proficiency affects time allocation, the study also compared how juveniles spend their time compared to adults. In support of my hypothesis, when juveniles were five weeks old, they foraged as successfully as adults. However, by the time of dispersal juveniles did not allocate their time similarly to adults, spending more time flying and less time perched than adults. Finally, the scanning rate and duration of foraging flights were similar to adults after the second week of successful foraging (around week six of age). Overall, these results indicate that foraging is a learned behavior that juveniles develop during their first few months of independence. Early development of proficient foraging abilities increases chances of survival. However, the development of proficient foraging abilities appears to precede the development of effective time allocation, which must occur sometime after independence.

Foraging behaviour in Drosophila melanogaster larvae is influenced by natural allelic variation in the foraging (for) gene that encodes a cyclic GMP – dependent protein Kinase (PKG), such that rovers (forR) traverse greater distances while foraging than sitters (fors). Foraging behaviour is also influenced by natural allelic variation in the wings up A (wupA) gene that encodes the Troponin-I protein (TnI). Specifically, wupAlow allele suppresses the dominance of the forR allele, turning rovers into sitters. The dominance of the natural wupA alleles and their interactions with allelic combinations in for has not been characterized. I conducted various crosses and found that wupA alleles exhibit incomplete dominance. More importantly, I found that allelic combinations of wupA and for gave rise to a range in larval foraging behaviour. In this study, I propose that this gradient effect in foraging behaviour is due to variation in levels of PKG activity and TnI phosphorylation potential.

Foraging behaviour in Drosophila melanogaster larvae is influenced by natural allelic variation in the foraging (for) gene that encodes a cyclic GMP – dependent protein Kinase (PKG), such that rovers (forR) traverse greater distances while foraging than sitters (fors). Foraging behaviour is also influenced by natural allelic variation in the wings up A (wupA) gene that encodes the Troponin-I protein (TnI). Specifically, wupAlow allele suppresses the dominance of the forR allele, turning rovers into sitters. The dominance of the natural wupA alleles and their interactions with allelic combinations in for has not been characterized. I conducted various crosses and found that wupA alleles exhibit incomplete dominance. More importantly, I found that allelic combinations of wupA and for gave rise to a range in larval foraging behaviour. In this study, I propose that this gradient effect in foraging behaviour is due to variation in levels of PKG activity and TnI phosphorylation potential.

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.

This project had 2 major objectives. The first objective was to assess how well the revised U.S. Fish and Wildlife Service Foraging Habitat Guidelines depict good quality habitat for the red-cockaded woodpecker (Picoides borealis) at Camp Lejeune, NC. To accomplish this, I used multiple linear and logistic regression to examine the relationships between fitness, habitat use, home range size, and habitat characteristics described in the guidelines. I assumed that habitat characteristics that confer quality were related to higher fitness, greater habitat use, and reduced home range size. To a large extent, the guidelines are validated. Red-cockaded woodpeckers responded favorably to habitat that mimics the historical, mature, and fire-maintained pine forests of the southeastern U.S., characterized by high densities of large pines, low densities of small and medium pines, and a lush herbaceous groundcover. Variables positively associated with habitat use and fitness were associated with reduced home range size, and those negatively associated with habitat use and fitness with increased home range size. Percent herbaceous groundcover was a significant regressor indicative of quality in every model. The second objective was to assess how well USFWS foraging partitions represent habitat used by red-cockaded woodpeckers. I conducted home range follows of 23 groups of red-cockaded woodpeckers and estimated the percentage of each home range encompassed by partitions of varying radii. The percentage of the actual home range included in the partition increased as a function of partition radius. The standard 800 m circular partition, on average, included 91% of the home range, but significant variation existed between groups. / Master of Science

Individual niche variation is increasingly being demonstrated in animal populations in a wide variety of species and taxa. Niche variation among individuals has important implications for the ecology, evolution and management of animal populations and is a subject of increasing interest. However, despite its widespread occurrence the causes and consequences of individual niche variation remain poorly understood. In this thesis I use the European badger (Meles meles), a well studied species of high ecological interest, as a model system to investigate individual niche variation. In order to achieve this I combine information on individual foraging niches derived via stable isotope analysis (SIA) of badger vibrissae with detailed life history and ecological data from a long-term study population to investigate the incidence, cause and consequence of individual niche variation within badger social groups. First I use the biomarker Rhodamine B to investigate vibrissae growth rates and patterns in badgers and demonstrate that the isotopic composition of a single vibrissa likely reflects diet over several months (Chapter 2). Next I explore the use of SIA as a tool to investigate badger diet, by comparing isotopic patterns to seasonal changes in diet measured using faecal analysis (Chapter 3). My results provide validation that SIA is powerful tool for investigating foraging variation in this species, and suggest that within badger populations substantial dietary variation may occur among individuals. Further investigation of isotopic variation Indicates that individuals within social groups differ markedly and consistently in their isotopic signature, independent of age and sex effects and that in some instances these differences are remarkably consistent across year (Chapter 4).This suggesting long term individual specialisation (Chapter 4). I find that the degree of this individual specialisation, and the relationship between specialisation and body condition is influenced by competition for resources (Chapter 5). Social groups with higher levels of competition exhibit greater specialisation and specialised individuals within these highly competitive environments are in better condition. Finally, I discuss the implications of these results for individual niche variation, for the application of SIA to study this behaviour and for badger ecology generally (Chapter 6). I also outline future directions for further research.

Stream living salmonids are generally regarded as drift feeders that rely upon their vision when foraging. It has been shown that salmonids become nocturnal at low water temperatures, but have a low foraging efficiency as light intensity is low, due to their dependence upon vision. Shifting from drift feeding to benthic feeding, has been suggested, and analyses of gut contents during winter have shown that the diet of salmonids mainly consists of benthic invertebrates. Most experimental studies of salmonid foraging have only offered the fish drifting prey or only given the fish access to benthic prey in total darkness. Such conditions rarely occur in nature and the importance of benthic foraging to salmonids may therefore have been underestimated. In this study I conducted a stream laboratory experiment to test if low light intensity caused juvenile Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) (age 0+) to forage more on benthic than drifting prey. The salmon foraged on both drifting and benthic prey during high light but consumed only benthic prey during low light (by one of six fish). Trout foraged on both drifting and benthic prey during both high and low light, but foraging efficiency was lower during low than high light and foraging efficiency was lower for benthic prey than for drifting prey. These results indicate that both species forage more opportunistically than previously thought. / Strömlevande laxfiskar anses generellt vara driftätare som förlitar sig på synen när de födosöker. Det har visats att laxfiskar blir nattaktiva vid låga vattentemperaturer, men har en låg födosökseffektivitet då ljusintensiteten är låg, på grund av sitt beroende av synen. Skifte från driftätande till att äta bentiska byten, har föreslagits, och analyser av maginnehåll under vintern har visat att laxfiskars diet huvudsakligen består av bentiska evertebrater. De flesta experimentella studier av laxfiskars födosök har endast erbjudit fisken driftande byten eller endast gett fisken tillgång till bentiska byten vid totalt mörker. Sådana förhållanden förekommer sällan i naturen och betydelsen av bentiskt födosök för laxfiskar kan därför ha underskattats. I den här studien utförde jag ett experiment i en laboratorieström för att testa om låg ljusintensitet fick juvenil Atlantlax (Salmo salar) och öring (Salmo trutta) (ålder 0+) att födosöka mer på bentiska än driftande byten. Laxen födosökte på både driftande och bentiska byten vid högt ljus men bara bentiska byten åts vid lågt ljus (av en av sex fiskar). Öringen födosökte på både driftande och bentiska byten vid både hög och låg ljusintensitet, men födosökseffektiviteten var lägre vid låg än hög ljusintensitet och födosökseffektiviteten var lägre för bentiska än förbiflytande byten. Dessa resultat indikerar att båda arterna födosöker mer opportunistiskt än vad man tidigare ansett.