Recent advances in sequencing technologies have provided an unprecedented window in the unseen biological world. Accompanying this revolution is a growing appreciation for the ubiquity and diversity of beneficial interactions between animals and the microbes they carry. Given the symbiotic roles of microbes in host nutrition, immunity, behavior, development, and nearly every other facet of host biology, it is becoming increasingly clear that any understanding of hosts and their evolution would be incomplete without also considering the microbial dimension. Yet despite the growing body of evidence that many of these partnerships are rooted deep in evolutionary time, the majority of studies have tended to focus on how the composition of the present-day microbiome is shaped by present-day factors. In order to place the microbiome in the larger context of host biology, a more complete understanding of the evolutionary interplay between hosts and their microbial associates is needed. Here, I use Odontotaenius disjunctus, a large xylophagous beetle found throughout eastern North America, to explore how its present-day gut microbiome has both shaped and been shaped by evolutionary processes that have acted on the host. First, I show that recent evolution in O. disjunctus reflects the influence of Pleistocene glaciation on the host’s demographic history. Next, I show that the present-day gut microbiome of O. disjunctus reflects both the influence of this recent host evolution and the more ancient influence of natural selection that has acted on the host to maintain these beneficial partnerships over a much longer timescale. Finally, I show that the persistence of certain members of the gut microbiome over evolutionary time may be explained by their role in host lignocellulose digestion. My findings demonstrate that, much like host genomes, the microbiome has been, is being, and will continue to be shaped simultaneously by forces of selection and neutrality along the arc of evolutionary history shared by these intimate partners.

Henslow’s sparrow (Ammodramus henslowii) winters in recently burned sites in pine savannas of the Southeastern United States. Previous studies have suggested that factors such as seed abundance and litter depth are important to wintering Henslow’s sparrows. My study asked how habitat variables including vegetation structure, seed abundance, and arthropod abundance predict Henslow’s sparrow site occupancy at Mississippi Sandhill Crane National Wildlife Refuge. In this study, Henslow’s sparrow more often occupied sites burned one growing season earlier than sites burned two growing seasons earlier, and did not occupy sites burned three or more growing seasons earlier. Data indicated that mass of graminoid seeds borne on stalks in November and minimum total seed mass were higher in occupied sites vs. unoccupied sites while litter density was lower. This suggests that Henslow’s sparrow selects habitats that may maximize foraging efficiency and probability of survival based on information about litter density and seed availability.

L'objet de cette thèse est d’explorer les mécanismes évolutionnaires à l'origine de la punition coûteuse chez les humains. Dans le chapitre 1, nous montrons que les comportements punitifs observés en laboratoire sont plus en adéquation avec des processus de sélection individuelle plutôt que de sélection de groupe. Dans le chapitre 2, nous fournissons des preuves empiriques que la décision de punir relève principalement de raisonnements intuitifs causés par une forte exposition à des environnements à réciprocité directe. Enfin, dans le chapitre 3, nous émettons quelques doutes quant à l'hypothèse (plutôt récente) que des stratégies de changement de partenaires pourraient se substituer à la punition coûteuse dans la nature. En somme, nos résultats soulignent le caractère maladaptatif du sentiment punitif tel qu'il se manifeste dans les jeux expérimentaux à un coup. / The aim of this thesis is to investigate the evolutionary roots of costly punishment in humans. In chapter 1, we show that available experimental data are more compatible with behavioral patterns sculpted by individual selective pressures than higher-population processes. In chapter 2, we provide experimental evidence that punishing decisions mostly rely on intuitive reasonings originally adapted to direct reciprocity environments. Finally, in chapter 3, we cast doubt on the (recent) claim that cheap partner switching opportunities make costly punishment anecdotal in the wild. In sum, our results emphasize the maladaptive nature of punitive behaviors observed in anonymous, one-shot laboratory settings.

There are three social dimensions within a family: parent-parent interactions, parent-offspring interactions, and offspring-offspring interactions. All of these interactions are subject to evolutionary conflict, which occurs whenever interacting individuals have divergent evolutionary interests. Family interactions and family conflict are often influenced by phenotypic and genotypic traits of the parents and the offspring. An important phenotypic trait is body size, which can affect fecundity, mating success, and fighting ability. An important genotypic trait is inbreeding status (i.e., whether an individual is outbred or inbred), which can influence its overall quality or condition. In this thesis, I investigate the independent and interactive effects of inbreeding and parental body size on family interactions in the burying beetle Nicrophorus vespilloides. I first show that the body size of the two parents influences the resolution of sexual conflict over the amount of parental care (Chapter 2) and over the consumption of a shared resource (Chapter 3). Here, the shared resource refers to the carcass from which both the parents and the offspring feed over the course of the breeding attempt. I then show that females that won or lost a fighting contest provide more care to their offspring compared to beetles with no fighting experience (Chapter 4). This indicates that female burying beetles make parental investment decisions based on their experience with a contest (which is independent of body size) rather than the outcome of that contest (which is dependent on body size):. In the second half of my thesis, I examine whether family interactions also influence and are influenced by inbreeding depression (Chapters 5–8). I find that a female's mating preference for an outbred versus an inbred male is conditional on her own inbreeding status: inbred females preferentially mate with outbred males, whereas outbred females are equally likely to mate with an outbred or an inbred male (Chapter 5). Even though sibling competition does not appear to have an effect on the offspring's inbreeding depression (Chapter 6), the presence of the mother during larval development can reduce the severity of inbreeding depression (Chapter 7), and this effect depends on the mother's body size (Chapter 8). In Chapter 9, I discuss the broader implications of these findings for evolutionary biology, ecology, and conservation biology.

It is clear that ecosystems are devastated after a volcanic eruption coats the landscape with a layer of ash; however, the ecological recovery of mammalian communities after eruptions is poorly understood. Volcanic eruptions vary with magnitude and type and only a fraction of them have been analyzed for effects on mammalian communities. To better understand mammalian community recovery, I investigated three different lines of evidence. First, I created a new numeric metric for statistically analyzing reproductive strategies in mammals and tested the impact of diet and body size on reproductive strategies within a phylogenetic framework as proof of concept. The trend of lower reproductive rates and larger body size hold true for herbivores and omnivores, but different trajectories exist for carnivores. Second, I investigated how species richness, evenness, and similarity change across volcanic boundaries in the 1980 Mount St. Helens (MSH), Washington, and 1914-1917 Mount Lassen, California, eruptions. Richness and evenness remain unchanged in Lassen. MSH saw an immediate drop in richness followed by an increase over five years to pre-eruptive levels. Chord distance analysis suggests no long-term change in the Lassen fauna. The pre- and post-MSH fauna are different from one another. The post-eruptive fauna was more similar to neighboring regions. Lastly, I tested whether the Oligocene horse Miohippus demonstrated morphological changes across the volcanic Picture Gorge ignimbrite (PGI; 29.069 Ma) in the John Day Formation of Oregon. Variation in upper and lower teeth was first tested to define a single species in the assemblage. Length, width, and wear of teeth were compared across the PGI and there were no significant differences between pre- and post-PGI assemblages. It is clear from my results that larger eruptions tend to have a greater impact on mammalian community recovery than smaller eruptions, but ultimately, mammalian populations are robust and the presence of neighboring communities is important for recolonizing devastated areas. There are two supplemental files associated with this dissertation, a CSV file of raw data downloaded for Chapter III and an excel file of raw data and coefficient of variation calculations for Chapter IV. This dissertation includes both unpublished and co-authored material.

Restoration of oyster reef structures rehabilitates habitats and the multi-level ecological communities built on eastern oysters (Crassostrea virginica), the keystone species. Quantitative descriptions of ecological interactions within a habitat are required to delineate essential fish habitats for management and protection. Parallel development of primary (oysters) and secondary trophic levels (benthic fishes) offer an ecological metric of restoration progress over time. The interaction between larval oysters and larval fishes (e.g., Gobiosoma bosc, Chasmodes bosquianus) is quantitatively examined. Oyster settlement estimates for Palace Bar reef, Piankatank River, Virginia are of the same order of magnitude as field densities of recently settled oysters. Benthic fish settlement estimates are within an order of magnitude of observed adult densities. Zooplankton community composition around the reef is temporally variable and plankton densities range from 10 2--106 animals per m3 across temporal scales. Nocturnal densities of naked goby and striped blenny larvae around Palace Bar reef were 3 to 4 orders of magnitude higher than densities observed during daylight hours. Diurnal changes in larval fish abundance near Palace Bar reef are related to ambient light intensities and diurnal vertical migration by prey species. Naked goby, striped blenny, and feather blenny (Hypsoblennius hentzi) larvae selectively consumed bivalve veligers, in multi-factorial laboratory feeding experiments. Temporal co-occurrence of larval oysters and larval fishes was not observed in 1996 field collections although historic oyster settlement data strongly support the probability of co-occurrence during most years. Two different methods are used to estimate the larval oyster - larval fish interaction in the absence of field data. Given existing oyster and fish demographics on Palace Bar reef, larval fishes have the capacity to drastically reduce, perhaps eliminate, local veliger populations if they co-occur. The strength of this interaction is directly related to oyster demography-fecundity relationships. In the absence of veligers, larval fishes consume other plankton taxa that are abundant around the reef. Naked gobies and striped blennies are generalists. Oyster reefs provide optimal rather than essential habitat. Reef restoration will facilitate development of related ecological communities by providing optimal habitat conditions for these ubiquitous estuarine species.

No description available.

No description available.

The first section of this dissertation describes the ichthyofaunal community of a mesohaline Chesapeake Bay April--November. Fish assemblages were sampled using two seine gears, a small seine that sampled 352 m 2 and a 914m haul-seine that sampled 144,473 m2. The small seine collected 32 finfish species. The larger gear captured 31 finfish species, including 17 that were not sampled by small gear. Sampled diversity was greater but density estimates were similar to those determined previously by other investigators using flume-net, drop-ring, and otter trawl techniques. Nocturnal abundance of larger fishes far exceeded daylight. Fish abundance and size distribution varied seasonally in both gears. The second section describes the littoral diet composition of striped bass (Morone saxatilis ), bluefish (Pomatomus saltatrix), and weakfish (Cynoscion regalis). These species were the most abundant piscivores sampled in the littoral zone. as in previous Chesapeake Bay diet studies the importance of pelagic prey increased with predator size, however, littoral diets evidenced greater dietary diversity and dependence on crustacean prey items. The third section consists of bioenergetic models that predict piscivore growth based on estimated nocturnal consumption and test energetic consequences of diel thermal refugia. Bluefish and weakfish were predicted to achieve better growth rates than those evidenced by field samples of aged fishes collected from across random Chesapeake habitats. Models predict that striped bass experience declining condition during warm water periods due to physiological stresses and poor prey acquisition. Theoretical diel relocation models illustrated how important species and age specific metabolic restrictions due to physical parameters are to fish health. Findings suggest that habitat specific physical dynamics may be as important as prey provision in determination of and spatial assessments of essential fish habitats.

In 1988 laboratory presentations, bay anchovy, and Atlantic menhaden tested positive as potential predators. Consumption of striped bass larvae by bay anchovy increased at higher prey densities to a maximum of 42 larvae/h at prey densities of 1,650/m&\sp3&. Examination of 229 stomachs of bay anchovy collected during peak spawning in 1988 and 1989 provided direct evidence of predation on striped bass eggs and larvae. The relationship between patterns of survival inferred from the back-calculation of juvenile hatchdates were compared with data sets describing predator and prey fields, egg production, food abundance, and changing environmental conditions during the 1988 and 1989 spawning seasons. The physical factors pH, rainfall, dissolved oxygen, and water temperature were measured at 30-minute intervals and observations of predator, prey, egg and larval densities were recorded weekly or semi-weekly. In 1988, a year of average recruitment, only 11% of the juveniles aged (n = 78) were born during the week of peak spawning when over 48% of the eggs were produced. In 1989, a year of high recruitment, the temporal distribution of juvenile hatchdates more closely followed the distribution of eggs with 30% of the juveniles (n = 96) born during the week of peak spawning when 40% of the eggs were spawned. Potential fish predators were collected in greater numbers during peak spawning in 1988 (61/100m&\sp3&) than during the same period of time of 1989 (12/100m&\sp3&). Water temperatures were lower during peak spawning in 1988 (16&\sp\circ&C) than during 1989 (19&\sp\circ&C). Also, prey items for first-feeding larvae decreased the week following peak spawning in 1988 from an average number of 194 to 74 individuals/l. Lower water temperatures and reduced food densities in 1988 may have produced a combined effect of prolonging developmental stages of striped bass eggs and larvae, thereby making them more susceptible to elevated predator densities. Dissolved oxygen values were inversely related to water temperature, reaching low values of about 6 mg/l after water temperature reached about 25&\sp\circ&C and spawning had ceased. Although pH values were usually around 7.0 throughout the 1988 and 1989 spawning seasons, pH depressions associated with rainfall were noted during both years.