This dissertation explores geographic and diachronic variation in Great Plains and Rocky Mountain Paleoindian (12,500-7000 14C years before present) forager exploitation of animal resources in order to explore how use of different habitats influenced land-use and subsistence strategies. To accomplish this goal, this study documented the full range of variability in the Paleoindian record using a combination of published data and new data. These patterns were then compared to explicit predictions derived from behavioral ecology and animal ethology and biology studies. The results, presented in this dissertation, allow the testing of several, often contradictory, important subsistence-settlement hypotheses in current Paleoindian research, specifically the ongoing debate about Paleoindian diet breadth and human causes of megafaunal extinction. Overall, there appears to be a covariance between environmental zone and forager land use. Paleoindian foragers structured their land use according to the presence and nature of a number of important resources within major environmental zones. Specifically, this study finds sites in grassland settings with low diversity of resources have lower artifact densities and are often dominated by exotic lithic raw materials. In these same areas prehistoric groups made almost exclusive use of large fauna. Sites in foothill/mountain or alluvial valley settings with ecologically high density and high diversity have higher proportions of short-term camps than do other areas and those camps have higher artifact density than do other types of sites. These sites exhibit a mixed use of small- and medium-sized game. Overall this study shows Paleoindian hunters had only modest impact on prey species.

The remarkable diversity of plant-feeding insects could be explained by the dynamics of their plant associations, where host plant shifts and specialization onto a small fraction of available plants may promote diversification. Neotropical Adelpha butterflies contain a large number of species, and previous work indicated the colonization of a novel host plant family (Rubiaceae) fueled its rapid diversification. However, accumulating host records indicate wide taxonomic host breadth at family level and below. Here, we categorize Adelpha diet breadth based on known host plant relationships across the Neotropics and from Costa Rica, Ecuador and Brazil. We also use a diet breadth index that identifies plants used in similar ways by Adelpha, pointing to potential plant traits that could facilitate or prevent plant-insect interactions. We find that diet breadth in Adelpha is not likely to change at different geographic scales, and that regional resource specialization was uncommon. Additionally, the diversification fueled by the switch to Rubiacae, appears to have led to some lowland-clade Adelpha species specializing on a restricted subset of host genera and species within Rubiaceae, as well as in Urticaceae. In contrast, the A. serpa-group shows generalization, with each species tending to feed on its own set of several unrelated plant families. Taken together, these results indicate that Rubiaceae and additional plant families appear as important ecological factors that have promoted adaptations in Adelpha and host plant family-level switches have not always had the same effect on diversification, corroborating the importance of Rubiaceae for this butterfly genus. Further research involving detailed phylogenies is needed to investigate associations between changes in diet breadth and speciation events, and test hypotheses of diet evolution.

Recent archaeological research within the American west, especially the Great Basin (e.g., Graf and Schmitt 2007), has perpetuated the notion of decreased residential mobility accompanied by increased diet breadth of hunter-gatherer groups during the Early Holocene. The earliest occupations at North Creek Shelter (NCS), a multicomponent site in south-central Utah, date to this time, specifically the Paleoarchaic (~10,000-9000 BP) and Early Archaic (~9000-7500 BP) periods. The zooarchaeological data from these levels were analyzed to determine whether Paleoarchaic occupations on the Colorado Plateau possessed greater residential mobility and narrower diet breadth than those of the Early Archaic, as they do in the Great Basin. However, upon examination of the NCS data, neither seems to be the case, or at least not to the dramatic degree observed to the west, as settlement and subsistence strategies remain fairly constant throughout the Early Holocene.

No description available.

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.

Submitted by Jaqueline Silva (jtas29@gmail.com) on 2014-12-08T17:37:44Z No. of bitstreams: 1 Tese-Thiago Santos-2013.pdf: 3081181 bytes, checksum: 2458be035ed935ff9e529ed2df6f9200 (MD5) / Rejected by Jaqueline Silva (jtas29@gmail.com), reason: on 2014-12-08T19:42:18Z (GMT) / Submitted by Jaqueline Silva (jtas29@gmail.com) on 2014-12-12T19:32:30Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Tese-Thiago Santos-2013.pdf: 3081181 bytes, checksum: 2458be035ed935ff9e529ed2df6f9200 (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-12-16T09:22:12Z (GMT) No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Tese-Thiago Santos-2013.pdf: 3081181 bytes, checksum: 2458be035ed935ff9e529ed2df6f9200 (MD5) / Made available in DSpace on 2014-12-16T09:22:13Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Tese-Thiago Santos-2013.pdf: 3081181 bytes, checksum: 2458be035ed935ff9e529ed2df6f9200 (MD5) Previous issue date: 2013-06-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / (Sem resumo em outra língua) / Dentre os mecanismos que geram as distribuições das espécies, tem sido atribuído um papel localàs interações biológicasenquanto que as causas de padrões regionais ou globais são atribuídas às variáveis abióticas.Recentemente,um número crescente de trabalhostem concluído que as interações biológicas interespecíficas apresentam efeitos significativos sobre os limites das distribuições das espécies e que a variação espacial em grande escala de atributos populacionais, como a densidade, é mais bem explicada pelas interações que pelas condições abióticas. Os objetivos deste trabalho são, portanto, mensurar a importância das interações biológicas na distribuição espacial das espécies, tanto em relação aos limites das distribuições quanto à variação espacial nas densidades populacionais e discutir novas técnicas para se incluir as interações interespecíficas nos modelos de distribuição potencial. No primeiro capítulo, um modelo estatístico de sistema de equações foi empregado para se verificar o efeito da competição entre duas espécies de cupins de montículos, Cornitermescumulans e Cornitermes silvestrii.No segundo capítulo, foi analisado o efeito da distribuição potencial de Crotalaria maypurensis (Fabaceae), sobre a distribuição potencial de Utetheisa ornatrix(Arctiidae). No terceiro capítulo, a distribuição de um predador de topo, Panthera onca, e a variação espacial de sua densidade populacional foram estimadas usando-se modelos alométricos de interação predador-presa.

Plant feeding insects comprise about 25% of all animal species on earth and play an important role in all ecosystems. Although we understand that their association with plants is a key-factor driving the diversification in this group, we still have large gaps in our knowledge of the underlying processes of this relationship. Female choice of host plant is an important event in the insect life-cycle, as it is a major determinant of the larval food plant. In this Thesis I studied different aspects of insect host plant choice and used butterflies from the family Nymphalidae as my study system. I found that butterflies have a well developed olfactory system and that they use odors when searching for food or host plants. However, the information obtained from the odor of host plants does not seem to be sufficient for the studied species to make a distinction between plants of different qualities. Interestingly, even when in full contact with the leaf they do not make optimal decisions. I show for example that a sub-optimal female choice may be mitigated by larval ability to cope with unfavorable situations. Moreover, species that utilize a broader set of host plants may not be very well adapted to all the hosts they use, but at the same time they may survive in areas where there is only a subset of the plants available. Lastly, differences in the evolution of life-history traits between species can account for differences in how each species realizes its lifestyle. Thus, by incorporating findings on mechanisms of host plant choice with the ecological and evolutionary context of a species, our ability to explain the dynamics of host plant choice and insect-plant interactions can be improved. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.</p>

Blue Catfish Ictalurus furcatus are native to tributaries of the Mississippi River but are now invasive in several Atlantic slope drainages. This includes subestuaries of the Chesapeake Bay, where their feeding ecology and potential impact on native species was largely unknown. We collected stomach contents from 16,110 Blue Catfish at 698 sites in three large subestuaries of the Chesapeake Bay (James, York, Rappahannock rivers). Cumulative prey curves revealed that sample size was sufficient for diet description, though 1,000 – 1500 stomachs were needed per river. Blue Catfish are opportunistic generalists that feed on a broad array of plant and animal material. Logistic regression models reveal that Blue Catfish undergo significant ontogenetic diet shifts to piscivory at larger sizes (P<0.01) though the lengths at which these shifts occur varies by river system (500 – 900 mm total length; TL). Over 60% of Blue Catfish stomachs contained other invasive species, primarily Hydrilla verticillata and Asian clams Corbicula fluminea. Canonical Correspondence Analysis (CCA) revealed that salinity and season explained the most variation in Blue Catfish diet, while Generalized Additive Models (GAMs) demonstrated that there is considerable spatiotemporal and length-based variation in predation of species of concern. Species of concern include American Shad, American Eel, and river herring, which are imperiled, and blue crab, which support valuable fisheries in Chesapeake Bay. Predation of American Shad, American Eel, and river herring was rare (max predicted occurrence in Blue Catfish diets = 8%), while blue crab was much more common in the diet (max predicted occurrence =28%). Predation of American Shad and river herring peaks in freshwater areas in April, while predation of blue crab peaks in brackish areas in October. Predation of all species of concern is highest for large catfish (500 – 1000 mm TL). Field and laboratory-based estimates of consumption rate revealed that Blue Catfish feed at similar rates as Channel Catfish Ictalurus punctatus, and daily ration is estimated to be 2-5% bodyweight per day during warm temperatures, while peak feeding (maximum daily ration) can approach 10% bodyweight per day. While consumption of imperiled species is rare, Blue Catfish could still have negative impacts on these species due to dense catfish populations. / Ph. D. / Native to the Mississippi River basin, Blue Catfish Ictalurus furcatus are the largest catfish species in North America; they can exceed 100 lbs and live for over 30 years. They were stocked in Chesapeake Bay as a sportfish 40 years ago and are now considered invasive. We performed a series of experiments to describe how invasive Blue Catfish fit in the food web, including diet and consumption rate analyses. Most of the Blue Catfish population is comprised of opportunistic generalists that feed on a diverse array of plant and animal material. We experimentally demonstrated that Blue Catfish tend to feed on whatever species are locally abundant. The most common prey were other species considered invasive in Chesapeake Bay; primarily Asian clams and Hydrilla verticillata, which is an invasive aquatic plant. Blue Catfish also eat other types of vegetation, clams, snails, crabs, fish, small invertebrates, mammals, birds, reptiles, and amphibians. Consumption of imperiled native fishes (like American Shad, American Eel, and river herring) was uncommon while consumption of the commercially-valuable blue crab was common, especially in brackish areas during the autumn. Blue Catfish consumption rates were similar to a closely related species, the channel catfish, and blue catfish can consume an estimated 2 – 5% of their body weight per day during the summer months, and up to 10% of their body weight per day during times of peak feeding. While consumption of imperiled species is rare, Blue Catfish could still have negative impacts on these species due to dense catfish populations

Harmonia axyridis is a ladybird native to Asia, but introduced widely as a biocontrol agent. It is invasive and detrimental to native species in North America, which meant its arrival in Britain was met with concern. Establishment was seen as an opportunity to track the spread of an invasive alien species (IAS) whilst also monitoring impacts on native species. The aims of this thesis were to examine the responses of native British ladybirds to the arrival of H. axyridis, to establish the effect of the IAS on native ladybirds when compared to other drivers, and to investigate the possible facilitation of the H. axyridis invasion by natural enemy release. Modelling ladybird distributions with life-history and resource-use traits found that species predatory on a wide range of prey families had larger range sizes than those which ate fewer prey types. This suggests that the wide diet breadth of the IAS is likely to have played a critical role in the species’ rapid spread. Dietary niche overlap between H. axyridis and native ladybirds showed positive correlation with declines of native ladybirds. This indicates that the IAS is playing an important role, but the significance of urbanisation suggests habitat destruction is also significant. Abundance of H. axyridis was influenced by habitat type and aphid abundance, but not by the native ladybird community, suggesting the spread of the IAS will not be slowed by biotic resistance. Harmonia axyridis is attacked by native parasitoids, but at a much lower rate than is the native Coccinella septempunctata, in line with natural-enemy release theory. There was no evidence of attack rate increasing with time since arrival in an area. Overall, H. axyridis is an extremely successful IAS, with detrimental effects on native ladybirds which are likely to continue.