Factors affecting flea densities in prairie dog colonies: implications for the maintenance and spread of plague

2014 Fall.Plague is a re-emerging, rodent-associated disease caused by the primarily flea-borne bacterium Yersinia pestis. The bacterium likely originated 1,500-20,000 years ago in Asia but has been transported by humans to multiple additional continents and islands where it degrades populations of a wide array of rodents. In the western United States, there is an urgent need to acquire a deeper understanding of plague because over half the rodent species of conservation concern occur within its introduced range. This dissertation describes research on fleas in colonies of black-tailed prairie dogs (Cynomys ludovicianus), colonial rodents that amplify Y. pestis in the Great Plains. Adult fleas were combed from live-trapped prairie dogs during June-August 2010-2012 in the short-grass prairie of Vermejo Park Ranch, New Mexico, USA. We evaluated correlations between flea densities and the attributes of soils, prairie dog colonies, and weather. Adult fleas were most abundant in portions of prairie dog colonies with coarse surface-soils and moderately textured subsurface-soils. Coarse surface-soils may allow precipitation to infiltrate to the depth of prairie dog nests, where the moisture could create humid microclimates that are preferred by fleas. Inside burrows, moderately textured soils may hold considerable amounts of water, some of which could evaporate into prairie dog nests, thereby creating humid microclimates. Although fleas tend to fare best under humid conditions, they were scarce in areas with very wet subsurface-soils, presumably because sodden soils can facilitate the accumulation of fungi and mites, some of which are lethal to fleas. We also studied the abundance of fleas in old colonies (initially 8-11 years-old) and young colonies (3-6 years). Fleas were 110% more abundant in old colonies and their abundance was positively correlated with the number of years since a colony was established. Fleas may accumulate to high densities in old colonies because prairie dogs have created deep burrows there, and deep burrows provide ectothermic fleas with humid microclimates and stable temperatures. Moreover, older burrows presumably contain a wealth of organic matter upon which flea larvae feed. Fleas desiccate under dry conditions and, consequently, their densities are thought to decline during droughts. At Vermejo, February-June precipitation was relatively plentiful in 2010 and 2012 but scarce in 2011, the driest spring-summer on record for New Mexico. Unexpectedly, fleas were 250% more abundant in 2011 than in other years. During the dry 2011 field season, prairie dogs were in poor condition and devoted little time to grooming. In contrast, during 2010 and 2012, prairie dogs were in 27% better condition and, when controlling for month and observer variation, devoted 450% more time to grooming. Prairie dogs provided with supplemental food and water during March-May 2012 were in 18% better condition and carried 40% fewer fleas during June-August. Increased flea densities during droughts may provide context for the maintenance and spread of plague. Three additional studies are presented herein. First, we developed a new method for combing fleas from hosts. The method and resulting data can be used with occupancy models to estimate prevalence rates for ectoparasites while accounting for imperfect detection. Second, we used the combing new method to estimate prevalence rates for the generalist flea Pulex simulans during June-August 2012. Prevalence estimates were >30% higher than indices from studies with substantial sample sizes for prairie dogs. If P. simulans can attain high prevalence on prairie dogs, the species may commonly serve as a bridge vector between Cynomys and other mammalian hosts of Y. pestis, and even function as a reservoir of plague. Third, a case study is presented to describe how Y. pestis can transform grassland ecosystems by devastating populations of prairie dogs and, thereby, causing (1) declines in native species abundance and diversity, including threatened and endangered forms, (2) alterations in food web connections, (3) alterations in the import/export of nutrients, (4) loss of ecosystem resilience to encroaching invasive plants, and (5) modifications of prairie dog burrows

Practice continuation agreements : a practice survival kit

https://egrove.olemiss.edu/aicpa_guides/1315/thumbnail.jp

The Effects of Parental Age and Housing Type on the Reproductive Success of the Purple Martin (\u3cem\u3eProgne subis subis\u3c/em\u3e)

The reproductive success of the Purple Martin is dependent upon many factors. This study measured reproductive success of the Purple Martin (Progne subis subis) based on parental age and type of housing used. Reproductive parental ages consist of adults (experienced breeders) and subadults (first time breeders). Housing types included in this study were aluminum housing, wooden housing, plastic gourds, natural gourds, SuperGourds, and mailbox housing. The reproductive success was defined as the percentage of the original clutch that fledged. Study sites were located in Alabama, Indiana, North Carolina, Oklahoma, Tennessee, and Virginia. Pairs mating nonassortatively by age group had lower reproductive success than adults and subadults that were paired assortatively. Purple Martins were the most reproductively successful in SuperGourds and the least reproductively successful in wooden housing. This study provides evidence that may be basis for further research, help support the conservation of the Purple Martin, and aid reproductive success on its breeding grounds

Cross Collaborations: Librarians Stepping Out of the Box to Serve Students

Despite declarations that libraries are the heart of the institution, they are frequently overlooked or taken for granted. Collaborations are a way librarians can more fully participate in the culture of the institutions they serve. A review of the literature finds an emphasis on collaboration with faculty members, both full-time and adjunct, but there is less emphasis on the many departments in academia that do not have faculty members. As academic librarians position themselves at the heart of their institutions, it is vital to work with all departments and not focus solely on faculty-based departments. This article highlights the literature on collaboration within academic institutions, examines current practices of librarians working with non-faculty members, and considers the best practices in creating and fostering collaborations beyond the faculty

Prairie Dogs, Persistent Plague, Flocking Fleas, and Pernicious Positive Feedback

Plague (caused by the bacterium Yersinia pestis) is a deadly flea-borne disease that remains a threat to public health nearly worldwide and is particularly disruptive ecologically where it has been introduced. We review hypotheses regarding maintenance and transmission of Y. pestis, emphasizing recent data from North America supporting maintenance by persistent transmission that results in sustained non-epizootic (but variable) rates of mortality in hosts. This maintenance mechanism may facilitate periodic epizootic eruptions “in place” because the need for repeated reinvasion from disjunct sources is eliminated. Resulting explosive outbreaks that spread rapidly in time and space are likely enhanced by synergistic positive feedback (PFB) cycles involving flea vectors, hosts, and the plague bacterium itself. Although PFB has been implied in plague literature for at least 50 years, we propose this mechanism, particularly with regard to flea responses, as central to epizootic plague rather than a phenomenon worthy of just peripheral mention. We also present new data on increases in flea:host ratios resulting from recreational shooting and poisoning as possible triggers for the transition from enzootic maintenance to PFB cycles and epizootic explosions. Although plague outbreaks have received much historic attention, PFB cycles that result in decimation of host populations lead to speculation that epizootic eruptions might not be part of the adaptive evolutionary strategy of Y. pestis but might instead be a tolerated intermittent cost of its modus operandi. We also speculate that there may be mammal communities where epizootics, as we define them, are rare or absent. Absence of plague epizootics might translate into reduced public health risk but does not necessarily equate to inconsequential ecologic impact

Spirituality: Take Me to a Higher Place

Panel Chair: Marta Moore Papers Presented: The Acceptance of Fate from a Man of God by Alexandra Mendez Acceptance Is Peace by Kane Stanglin Hindu Beliefs in Bhagavad-Gita by Laura A Eads Analysis of \u27The Sovereignty of Goodness of God\u27 by Kyle Crossli

Self-Monitoring of Stressors as an Additive Component to a Stress Management Training Protocol

The purpose of this study was to examine whether or not self-monitoring of stressors and physiological response to stressors enhances the effectiveness of a stress management technique, specifically relaxation training. The primary hypothesis which stated that the RSMS group would experience a greater reduction in depression (on the Beck Depression Inventory), and enhancement in self-efficacy (on the General Self-efficacy Scale) than all other groups, was not supported

The K600 Focal Plane Polarimeter

This research was sponsored by the National Science Foundation Grant NSF PHY-931478