Experiment s were conducted to see if Erwinia amylovora (Burrill) Winslow et al. overwinters inside living host tissue in Utah. Bacteria, collected from apple, pear, mountain ash, chokecherry and Pyracantha, were used in the experiment. Isolates taken from buds and inner bark plated on nutrient yeast dextrose agar, we re tested by serological and bacteriophage techniques. Those showing positive tests were then inoculated into Bartlett pear seedlings to test virulence. Both virulent and avirulent isolates were isolated from each species of plant in the experiment. Pathogenic bacteria were isolated from diseased tissue near cankers, as well as from apparently healthy inner bark as far as six inches below the cankers. Pathogenic bacteria were also isolated from healthy appearing buds in the vicinity of cankers. Nearly 15 percent of isolates from hosts other than apple and pear were pathogenic to Bartlett pear seedlings. A good deal of variation existed among the bacterial isolates. Antisera developed from four isolates of Erwinia amylovora proved to be a good means of identification for the pathogen.

No description available.

The redbanded stink bug, Piezodorus guildinii (Westwood) (Hemiptera: Pentatomidae), is a non-native pest of soybeans in the Americas outside of the Carribean. Mortality of overwintering adults due to cold exposure has been implicated as a major driver of interannual fluctuations in the occurrence of P. guildinii in the southeastern United States, but formal investigations of drivers, including factors other than cold temperatures, are rare. We conducted overwintering assays with field-collected P. guildinii to quantify survival and coupled historical occurrence with climatic data to develop a species distribution model. We found that leaf litter provides substantial insulation from lethal temperatures and thus increases the potential for overwintering survival of P. guildinii. Our species distribution model indicates that the northern extent of the insect’s range is limited by winter temperatures, but that can potentially expand the range hundreds of kilometers in a growing season.

Mule deer are an important rangeland grazer, large prey species, and game animal for the state of Utah, so herd size is monitored and managed actively. A significant cause of population decline is poor overwintering survival, including from the lack of available forage during winter months. Mule deer energy storage is correlated with greater overwintering success, so physical estimates of energy storage including body condition score (BCS), rump fat (RF), and loin thickness (LT), can be used to track and predict a herd's health. Current methods of collecting deer information are costly, time consuming, and cause physical stress to deer, so here we sought to test if a microbiome analysis could be used to predict deer overwintering success. We analyzed nearly 1000 fecal samples collected from deer in Utah over a five-year period. We found that the microbiome composition of these samples shared characteristics with published reports of other reported ruminant species. Also, the location and time when the samples were collected significantly influenced mule deer microbiota composition and abundance. We found that there is a relationship between microbes and health measures (BCS, RF, LT), including some microbial abundances that could predict the health measures of mule deer several months ahead of time. There were also microbial groups whose abundances were significantly correlated with the latitude and elevation of the deer. Finally, a longitudinal analysis on a subset of sampled deer produced slightly different results than the broad analysis of all samples, including suggesting that some of the differences in microbiota composition with time may have been related more to sampling distinct deer at different time points, rather than that the deer microbiota composition changed with time. . These results suggest possible candidate microbial taxa for use in developing assays to replace current methods of measuring and tracking deer health.

No description available.

No description available.

Little is known about the tick populations found within the central Appalachian/southwestern region of Virginia. The main focus of this research was to better assess local tick communities in the central Appalachian-Southwestern region of Virginia, which was addressed by determining species diversity, habitat associations, seasonal phenology, pathogen prevalence, and ecological factors that influences tick presence and abundance. A field study was conducted from June 2019 - November 2020 across 8 counties and 3 habitat types. Forested habitats exhibited greater tick species diversity than pasture and urban habitats. Each tick species was observed to be associated with particular habitats. The presence of B. burgdorferi sensu stricto (causative agent of Lyme disease), the human variant of A. phagocytophilum (causative agent of human granulocytic anaplasmosis), and Powassan virus (the causative agent of Powassan encephalitis) were detected in collected field specimens, suggesting a significant threat to public health. The detection of Powassan virus RNA in local Ixodes scapularis ticks is the first evidence of this viral pathogen within the region. The overwintering abilities of ticks, whose populations are expanding or becoming more invasive, including Haemaphysalis longicornis, Amblyomma americanum, and Amblyomma maculatum, were examined through a combination of laboratory and field experiments. Amblyomma americanum and H. longicornis nymphal ticks had a lower supercooling temperature than adult ticks, suggesting their potential to overwinter better; A. maculatum nymphs had similar average supercooling temperatures as the other two species at nymphal stage. Via a field experiment, A. americanum, H. longicornis, and A. maculatum were subjected to natural elements of a Virginian winter in a two-factor design investigating elevation and potential insulation coverage. Elevation and insulation coverage were found to have no significant impact on the overwintering survival of H. longicornis and A. americanum. However, the life-stage of the tick was determined to be a significant factor that dictated the survival of ticks of these species. Overwintering survival of Amblyomma maculatum nymphs was influenced by insulation (proxied by leaf litter); which may be attributed to this tick's preference of drier climate. Low overwintering survival suggests that a tick may not be able to establish a permanent population within the area. / Master of Science in Life Sciences / Ticks can transmit many pathogens, bacteria or viruses that cause disease, to both humans and animals. Diseases associated with ticks can include Lyme disease, Human Anaplasmosis, Ehrlichiosis, Rocky Mountain spotted fever, as well as viral illnesses. The pathogens that cause these diseases are vectored by specific tick species. Currently, there are no published reports of tick species present within the central Appalachian/southwestern region of Virginia. A study to determine local tick populations presence and the factors influencing their maintenance in the environment was conducted. Additionally, field collected specimens were screened to assess pathogen prevalence within the region. I confirm the presence of Borrelia burgdorferi sensu stricto (causative agent for Lyme disease), Anaplasma phagocytophilum (causative agent for Human Granulocytic Anaplasmosis), and Powassan virus within Ixodes scapularis, commonly referred to as black-legged ticks. Habitat (forest, urban, pasture) was a significant influencing factor on the presence of I. scapularis, Amblyomma americanum, and Haemaphysalis longicornis (e.g., the latter species was predominantly found in pasture habitats). Secondly, I investigated how well three sympatric tick species would overwinter within the region. Survival of a tick is heavily dependent upon their ability to withstand desiccation, obtain a blood meal from a host, mate, and reproduce. Certain ticks may be limited to certain regions based on elevation, temperature, and relative humidity. I investigated the influence of elevation and insulation coverage (presence of leaves vs. no leaves) on A. americanum (Lone star tick), H. longicornis (Asian longhorned tick), and A. maculatum (Gulf Coast tick). Elevation and insulation coverage had no significant impact on the overwintering survival of the Lone star and Asian longhorned ticks. Tick survival was mainly dictated by what life-stage they were in; Lone star ticks survived better as adult than at other life stages. Asian longhorned ticks survived better as nymphs than larva and adults. Insulation coverage influenced the overwintering survival of the Gulf Coast tick. These ticks survived better with no leaves, which may be associated with their preference of drier climates.

The brown marmorated stink bug (Halyomorpha halys) (Stål) is known for overwintering in human homes. Studies were conducted to understand the behavior of adult bugs in response to characteristics of potential overwintering structures including gap sizes, light, and presence of dead conspecifics. In a test where bugs were placed in increasingly tight boxes, most bugs settled in gaps 4.5 - 5.5 mm high. None settled in a space less than 3.5 mm high. In boxes with constant tightness, bugs tended to move to the back, and primarily settled along walls and in corners. In both box types, bugs tended to turn and face the cavity entrance during settling. In tests of responses of disturbed overwintering bugs to common household light bulbs over the course of a year, bugs were taken from shelters and exposed to lit bulbs. Bug responses were seasonal, with attraction to light bulbs in spring and summer, but little or no consistent response in fall or winter. The lack of response occurred more often at night than in afternoons. Because not all bugs survive the winter, corpses can accumulate. Single shelter-seeking H. halys were found not to respond to the presence of dead aggregations from the previous years unless touch was possible, in which case aggregations were joined. Dead aggregations from the same year had a repellent effect. Presence of a single dead bug from the same year did not provide any survivorship advantage to overwintering bugs. Results suggest possible improvements to trap shelters. / Master of Science in Life Sciences / The brown marmorated stink bug (Halyomorpha halys) is known for overwintering in human homes. This research investigated the responses of these bugs to some characteristics of overwintering structures, including crevice tightness preference, light sources, and dead bugs leftover from previous years. Tightness experiments indicated that bugs in crevices with hard walls prefer to settle in spaces between 4.5 and 5.5 mm high. Bugs also tended to stay on the floor, go back as far as they could, and face the entrance of the crevice. These findings will help improve overwintering box designs for collection and research, and will help pest control professionals focus their efforts. When bugs were disturbed and exposed to common household light bulbs, they tended to move toward the bulbs in late summer and in spring, but responded less in fall and winter, and responded more often in the afternoon than at night. Bugs were also exposed to other dead bugs in several ways. When lone bugs were exposed to groups of dead bugs from previous years, they went to them only if they could touch them. Single dead bugs had less of an impact. Exposure to groups of dead bugs from the same year drove live bugs away. Overwintering brown marmorated stink bugs do not appear to eat other bugs that have recently died. These results suggest several possible improvements to the designs of trap shelters used for research and control.

The overwintering ranges of North American bird populations are shifting and the winter ranges of south Florida’s landbirds remain understudied. Expert-drawn range maps used for scientific studies and environmental public policy could therefore be depicting inaccurate ranges for many migratory birds. This study used citizen science data from eBird (2001–2017) to evaluate patterns in overwintering avian species richness and identify discrepanciesin expert-drawn species range maps for overwintering passerines in south Florida. Most of Florida’s overwintering bird species were sighted in south Florida. Of the species observed there between 2001 and 2017, 66% had range map discrepancies. Fifteen target species were examined in the present study and fourteen of them were sighted in south Florida throughout the winter. None of these were depicted on range maps as overwinterers. These results showed that current expert-drawn range maps likely misrepresent the current winter ranges of passerine species in south Florida.

Within social insect colonies, sterile workers are responsible for brood care, while queens are the primary egg-layers. These reproductive caste differences are often accompanied by pronounced morphological distinctions. Queen and worker phenotypic differences are particularly remarkable considering caste is environmentally, rather than genetically, determined. Environmental caste determination can produce intralocus genetic conflict between castes, particularly when homologous traits are highly dimorphic. Therefore, when studying the evolution of social insect caste dimorphism, one must consider the genetic architecture underlying phenotypic expression as well as the selective pressures that have shaped caste morphology. This dissertation presents the results of four studies that investigated factors affecting caste morphology in the social wasp Vespula maculifrons. The first two studies focused on identifying queen morphological traits that were positively associated with queen fitness and would therefore be subject to selection. Queen length, specifically gaster length, was positively associated with overwintering survival and was consistently associated with mating success. Both of these findings suggest that queen gaster length is under selection during two life-history events, mating and overwintering, in which workers do not participate. These findings provide empirical support for the adaptive evolution of a caste dimorphic trait. The third and fourth studies used classical quantitative genetic and morphological analyses to examine the genetic architecture underlying caste dimorphism in V. maculifrons. I determined which traits were under caste-specific selection by analyzing trait allometries and the levels of genetic control, variation, and dimorphism of traits between castes. Little genetic variation for morphological trait size was detected for most worker and queen traits, suggesting a strong influence of environment on phenotypic variation. Additionally, analyses of trait allometries indicated that several queen traits (mass, thorax width and length) were under queen-specific selection. The relationship between thorax length, gaster length, and overall body size is further evidence of selection on length in queens. Overall, these studies provide evidence for the importance of queen-specific selection in the evolution of caste dimorphism. When placed in the broader context of caste evolution, they point to the importance of life-history in shaping the genetic architecture underlying caste dimorphism.