An introductory section provides a review for the role of bats as reservoirs of infectious diseases, and highlights the rationale for investigations of host life history, ecology, and evolution in regard to bat epizootiology. Chapter 1 presents field investigations of life history, ecology, body condition, and rabies virus neutralizing antibody seroprevalence in six natural colonies of Brazilian free-tailed bats from caves and bridge roosts in Texas. Chapter 2 presents a replicate field investigation of life history, ecology, body condition, and rabies virus neutralizing antibody seroprevalence in six natural colonies of Brazilian free tailed bats from bridges and bat house roosts in Florida and Georgia. Chapter 3 evaluates the relative influence of local and landscape factors on life history, ecology, body condition and rabies virus neutralizing antibody seroprevalence in Brazilian free-tailed bats in the southern United States. Chapter 4 describes the role of host population genetic structure in big brown bat rabies virus epizootiology, and describes comparative pathogenicity of two big brown bat rabies virus isolates across several captive experimental infection studies. The information presented has been used in the development of individual, population, and metapopulation models of rabies virus epizootiology in bats.

Patterns of geographic variation in body size and cell size have long fascinated biologists, and climatic variables have often been considered to explain such patterns. Environmental temperature can profoundly influence the phenotype, including body size. of ectotherms, and reptiles in particular. This dissertation presents four studies that examine how temperature shapes morphology on developmental and evolutionary timescales in the green anole lizard, Anolis carolinensis. The first three studies examined variation in and phenotypic plasticity of cell size and body size through laboratory experiments using eggs and juveniles from wild-caught females in five populations of A. carolinensis. The fourth study examined geographic variation in body size and cell size in 19 wild populations across the species range. Temperature-induced plasticity in cell size but not initial hatching size was demonstrated. However, subsequent differences in growth rates among juveniles reared in a common laboratory environment indicated a latent effect of incubation temperature on body size. Sampling of body size and red blood cell size from four eastern populations in the range suggested a latitudinal trend in body size and cell size. Rearing of offspring in a common environment indicated differences among populations in juvenile and, potentially, embryonic growth rates contributing to divergence in adult body size. Extended sampling of body size and cell size from 19 populations throughout the range, however, showed that inclusion of Florida populations heavily skewed geographic patterns because of the smaller body and cell size of anoles in the peninsular state. Exclusion of these populations revealed a negative relationship between latitude and both body size and muscle cell size, and no geographic trends in red blood cell size.

The purpose of this study was to investigate geographic and temporal diversification patterns in the barcheek darter species group. Specifically, my two questions were “Is there geographical structure of alleles or haplotypes within currently recognized species that is suggestive of unrecognized, or cryptic, species diversity within the clade?” (geographic diversification pattern) and “How old are inter- and intraspecific divergence events in the evolutionary history of the clade?” (temporal diversification pattern). A three gene dataset from 159 barcheek individuals of two mitochondrial coding regions, cyt b and ND2, along with a nuclear intron, S7, was analyzed using parsimony and Bayesian phylogentic methods to answer the first question. Divergence times were estimated using fossil calibration of this Bayesian phylogeny in order to answer the second question. Three barcheek species were found to have significant population structure suggestive of cryptic species diversity. E. basilare in particular was recovered as being comprised of five reciprocally monophyletic clades endemic to each of the major tributaries to the upper Caney Fork River. Inter- and intraspecific divergence events were found to be relatively old in the clade, nearly all pre-Pleistocene, with a crown node age estimated at 12.68 mya. These results are discussed in light of the present understanding of the tempo of diversification in the darter radiation.

Piperaceae is unique among Piperales because it is the only tetrasporic group in the order and a great deal of diversity in the ontogenetic trajectories of the female gametophyte is found in its genera. The evolutionary developmental origin of the sixteen-nucleate female gametophyte remains unclear in the family until now. In Piperaceae, Manekia has been identified as sister to Zippelia, and this clade is sister to core Piperaceae (Piper, Peperomia). This research is the first attempt to understand the development of the female gametophyte of Manekia naranjoana in order to provide critical data on the origin of tetrasporic development in the family. Several aspects of the floral biology and phenological events taking place in the ovary, the flower and the inflorescence were explored. Manekia has a tetrasporic, sixteen nuclei female gametophyte, that is being produced from a single archesporial cell. The egg apparatus is located at the micropylar end of the female gametophyte. It is constituted of three cells, two synergids and an egg. The central cell nuclei consist of two nuclei, one from the micropylar end and the other one from the chalazal one. The eleven remaining nuclei are arranged toward the chalazal pole of the female gametophyte, and sometimes fuse. This description corresponds mostly to the Drusa type. But Penaea type is also occasionally reported for first time in this study for the genus. Manekia and Zippelia share a similar structure of the female gametophyte with a total of 16 nuclei, and two nuclei in a central cell suggesting a triploid endosperm. The transition from monosporic to tetraporic female gametophyte development can be explained through the theory of modular construction and several kind modifications in the ontogenetic trajectories. Heterochronic and heterotopic changes, additions, and deletions in the development of the female gametophytes reflect evolutionary histories of the particular taxa implicated. A great deal of plasticity in terms of lack of polarity and nuclear fusion of antipodals was found in the chalazal module of the female gametophyte of Manekia.

Agroecosystems produce insects in great abundance, with episodic irruptions in time, and patchy distributions in space. In the industrial scale agroecosystems of south-central Texas, millions of Brazilian free-tailed bats (Tadarida brasiliensis) consume these insect pests. In the past decade, growers in Texas have planted transgenic Bt (Bacillus thuringiensis) crops on a large scale, which may reduce populations of target insect species by up to 95%. To investigate potential impacts of this evolving agricultural landscape on insectivorous bats, I examined the response of foraging bats to emergences of insects from replicate Bt and non-Bt fields of corn and cotton in the Winter Garden region of south-central Texas. I quantified bat activity using ultrasonic detectors deployed simultaneously in Bt and non-Bt fields. I measured insect activity using pheromone traps and video imaging. Professional crop consultants scouted fields to determine dates of insect emergence. We recorded 92% more echolocation calls, 62% more AnaBat files, and 257% more feeding buzzes over agricultural fields during periods of local insect emergence. During these insect emergence periods, bat activity was correlated with the abundance of moths and negatively related to the distance between foraging sites and roosting sites. In general, Bt crops did not have a measurable impact on the activity of bats except at one site where moths were more abundant over non-Bt crops versus Bt crops. Foraging bats showed a delayed response to moth abundance, which is consistent with the hypothesis that roosts serve as information centers that enhance foraging efficiency. The ability of millions of bats to exploit localized patches of prey across a large area provides further evidence of their pest control service. This economically important pest control service extends beyond growers in Texas, as the populations of moths produced in agroecosystems in Texas influence agricultural production on a continental scale.

To assess changes in coccinellid communities subsequent to the introduction of two non-native species, Coccinella septempunctata and Harmonia axyridis, ladybird numbers were monitored over a 20 year period at Mt. Saint Helens, Washington and in three years between 1996 and 2004 in southwestern Virginia. Surveys conducted at Mt. Saint Helens included pre- and post- invasion years for both non-natives. At Mt. Saint Helens, C. septempunctata and H. axyridis both increased in abundance, accompanied by declining numbers of the native ladybird Adalia bipunctata at one of the two Washington sites and of the native ladybird Coccinella transversoguttata at both sites. Declines in these two native ladybirds are strongly correlated with increases in the two introduced species. Given the long study period at Mt. Saint Helens, the declines in these two natives appear to be real trends. Further research is required to determine if the introduced species have indeed been the direct cause of the declines, and to find the mechanisms of interactions. The arrival of C. septempunctata to Virginia predated the first year of this study likely by several years. Harmonia axyridis was detected in Virginia by 1993, three years prior to the first study year in this state. In Virginia, only one introduced species, H. axyridis, showed an increase during the study and this was at one site only. This increase was not accompanied by declines in native species. In fact, the native Coleomegilla maculata also increased at the site during this period. Lack of evidence for declines in native species in Virginia may simply indicate that native species were not affected by the two introduced species, or it may reflect lack of power in the data to detect changes. Alternatively, any changes to the ladybird community may have occurred prior to the start of this study.

Rare species with fragmented distributions often exhibit reduced levels of genetic diversity within populations. However, life history traits such as long lived perennial habit and outcrossing mating system, are associated with high levels of within species genetic variation being partitioned within populations. Schisandra glabra (Schisandraceae) is a rare basal angiosperm with a fragmented distribution across the southeastern US and in a disjunct population in cloudforest of Mexico. The species’ clonal reproduction by rhizomes, confounds the delineation of genetically distinct individuals in the field. The patterns of genetic diversity and clonality in 10 populations of S. glabra were investigated using AFLP markers. I found a surprising number of distinct genetic individuals in the two populations sampled on 3m grids, with 31 unique genotypes out of 42 samples at Wolfpen Creek, KY, and unique genotypes in all 48 samples from Panther Creek, GA. AMOVA of 237 individuals from 10 populations revealed that the largest portion of the genetic variation is found within populations (58.0%; P<0.0001), and 27.7% (P<0.0001) of the genetic variation is partitioned between the US and Mexico S. glabra populations. Population structure was also detected between the US and Mexico populations, but no structure was detected between the majority of the US populations. The genetic differentiation of the disjunct population in Mexico, may be the result of a Pliocene or Miocene vicariance hypothesized for many species with similar distributions. The high levels of genetic diversity found within populations are evidence of historical gene flow between the US populations, and the preservation of genetic diversity by the long lived species in its present fragmented distribution.

The life history, behavior, and ecology of Etheostoma sagitta (Jordan and Swain) were studied in the Cumberland River system in Tennessee. Diving equipment was utilized in making observations on macrohabitat, microhabitat, distribution, seasonal and diurnal activity, feeding behavior, migration, territoriality, associated species, competition, and population density and structure. Courtship, reproductive behavior, and diurnal activity were studied primarily in an experimental raceway. Feeding behavior and territoriality were studied in the raceway and in a 77.5-1. (20-gal.) aquarium. Parasites, longevity, age and growth, ova numbers and maturation, sex ratios, and food habitats were examined in the laboratory. Etheostoma sagitta was found in clear as well as turbid streams. Habitats ranged from intermittent pools to small rivers. It more frequently occurred in streams with small rubble bottoms, but microhabitat varied with size class and season. Adults more frequently inhabited mid-channel portion of the stream while juveniles inhabited the periphery during the fall, winter, and spring. Migration was only noted in No Business Creek. Associated species and competition are discussed, with special reference to other Etheostoma. Quantitative diurnal activity studies indicated that activity peaked in late morning (1100 hrs.) and probably ceased by 1900 hrs. Large males and females were more active than smaller fish. Juvenile fish fed mainly upon copepods, cladocerans, and dipteran larvae. E. sagitta is sexually dimorphic. Males reached the height of coloration in spring. The color patter was retained throughout the year in adults but intensity faded after the breeding season. Females were only slightly brighter in the spring. Courtship and reproductive behavior began with construction of of a gravel depression by an adult male. During this activity, territorial behavior was centered upon the gravel nest area. This was the only time that territorial behavior was observed. E. sagitta attains its greatest growth increment during the first year. Over the period of study, population densities did not change drastically; longevity was 4 years. A sex ratio of 1.04 males per females was observed.

Piperaceae is unique among Piperales because it is the only tetrasporic group in the order and a great deal of diversity in the ontogenetic trajectories of the female gametophyte is found in its genera. The evolutionary developmental origin of the sixteen-nucleate female gametophyte remains unclear in the family until now. In Piperaceae, Manekia has been identified as sister to Zippelia, and this clade is sister to core Piperaceae (Piper, Peperomia). This research is the first attempt to understand the development of the female gametophyte of Manekia naranjoana in order to provide critical data on the origin of tetrasporic development in the family. Several aspects of the floral biology and phenological events taking place in the ovary, the flower and the inflorescence were explored. Manekia has a tetrasporic, sixteen nuclei female gametophyte, that is being produced from a single archesporial cell. The egg apparatus is located at the micropylar end of the female gametophyte. It is constituted of three cells, two synergids and an egg. The central cell nuclei consist of two nuclei, one from the micropylar end and the other one from the chalazal one. The eleven remaining nuclei are arranged toward the chalazal pole of the female gametophyte, and sometimes fuse. This description corresponds mostly to the Drusa type. But Penaea type is also occasionally reported for first time in this study for the genus. Manekia and Zippelia share a similar structure of the female gametophyte with a total of 16 nuclei, and two nuclei in a central cell suggesting a triploid endosperm. The transition from monosporic to tetraporic female gametophyte development can be explained through the theory of modular construction and several kind modifications in the ontogenetic trajectories. Heterochronic and heterotopic changes, additions, and deletions in the development of the female gametophytes reflect evolutionary histories of the particular taxa implicated. A great deal of plasticity in terms of lack of polarity and nuclear fusion of antipodals was found in the chalazal module of the female gametophyte of Manekia.

Rare species with fragmented distributions often exhibit reduced levels of genetic diversity within populations. However, life history traits such as long lived perennial habit and outcrossing mating system, are associated with high levels of within species genetic variation being partitioned within populations. Schisandra glabra (Schisandraceae) is a rare basal angiosperm with a fragmented distribution across the southeastern US and in a disjunct population in cloudforest of Mexico. The species’ clonal reproduction by rhizomes, confounds the delineation of genetically distinct individuals in the field. The patterns of genetic diversity and clonality in 10 populations of S. glabra were investigated using AFLP markers. I found a surprising number of distinct genetic individuals in the two populations sampled on 3m grids, with 31 unique genotypes out of 42 samples at Wolfpen Creek, KY, and unique genotypes in all 48 samples from Panther Creek, GA. AMOVA of 237 individuals from 10 populations revealed that the largest portion of the genetic variation is found within populations (58.0%; P<0.0001), and 27.7% (P<0.0001) of the genetic variation is partitioned between the US and Mexico S. glabra populations. Population structure was also detected between the US and Mexico populations, but no structure was detected between the majority of the US populations. The genetic differentiation of the disjunct population in Mexico, may be the result of a Pliocene or Miocene vicariance hypothesized for many species with similar distributions. The high levels of genetic diversity found within populations are evidence of historical gene flow between the US populations, and the preservation of genetic diversity by the long lived species in its present fragmented distribution.