The Melanoplus scudderi species group, when erected by Blatchley, contained six species. The revision of the group presented here describes 21 new species and establishes the Melanoplus carnegiei group, all of which are associated with grasslands in the Southeast. Analysis of DNA barcoding data, suggest that the technique does not adequately delineate species based on the morphological concepts presented here, but did produce three broad mitochondrial DNA clades that correspond to the Apalachicola and Mississippi River discontinuity phylogeographic pattern displayed by several other organisms in the Southeastern United States. This pattern is attributed to vicariant events resulting from Pleistocene glaciation. A hypothetical evolutionary history of the Scudderi and Carnegiei groups is presented. Natural grasslands historically covered a significant portion of the southeastern United States. These grasslands contribute significantly to the biodiversity of the region with many endemic or rare species inhabiting them. Grasshoppers are important components of temperate grassland ecosystems, but no comprehensive review of the grasshopper fauna of southeastern grasslands had previously been conducted. Here a review of the regional fauna was conducted. In total, 211 grasshopper species have been documented in the Southeast, with 111 species (53%) being endemic to natural grasslands. Of particular note, 74 species (34% of the regional fauna) are endemic to the longleaf pine ecosystem. Many of the non-endemic grasshopper species inhabiting grasslands in the region are disjunct from larger populations west of the Mississippi River, presenting interesting biogeographic distributions. Additionally, a cluster analysis of grasshopper community composition from several types of grasslands in the region supports the faunal distinctiveness of the different types grasslands in the region.

Tornado research conducted across the southeastern United States suggests two peak tornado maxima. However, few studies have distinguished between the thermodynamic and shear environments between cool-season and warm-season tornadoes. Incorporating 100 mb mixed layer parcels, mean thermodynamic and shear parameters for non-significant (F0?F1) and significant (F2?F5) tornado environments were calculated. Cool-season tornado environments were characterized by relatively low amounts of instability and high shear. On the other hand, warm-season tornado events were characterized by higher amounts of instability and generally less shear. The Energy Helicity Index (EHI) remained nearly constant suggesting a balance of instability and shear between the tested seasons. During the cool-season, an increase in instability appears to distinguish between tornado strengths. Yet, an increase in shear during the warm-season may be indicative of significant tornado environments.

Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: In southern Africa, the ticks Amblyomma hebraeum and Hyalomma rufipes are the main vectors of animal Heartwater and human Crimean Congo Haemorragic Fever, respectively. In order to investigate the phylogeographic structure of these ectoparasites, population genetic studies were conducted throughout southern and partly eastern Africa. Knowing the levels of genetic diversities and population connectivities throughout the species’ native ranges, may be useful for implementing control measures (cross country borders for example), evaluate the potential for drug resistance in introduced locations as well as for elucidating its vectorial capacities in the region. Mitochondrial cytochrome oxidase I (COI) and the internal transcriber spacer 2 (ITS-2) sequences were obtained from eleven sampled localities. In general, haplotype networks and molecular diversity values showed significant genetic structure between most of the sampled populations. Fu’s Fs and mismatch distributions suggested recent population expansions following a bottleneck. A Mantel regression analysis also revealed a significant isolation by distance for H. rufipes. Comparing the two species, H. rufipes showed much stronger signals of geographic genetic population structure in relation to A. hebraeum. A single taxonomic unit is suggested for A. hebraeum while H. rufipes is characterized by the existence of at least three distinct genetic assemblages that may point to incipient speciation. The difference between the two species may be explained by gene flow restriction within the region, by the number of hosts required to complete the life cycle (2 and 3 hosts, respectively), type of host species (domestic and wild animals; small and big mammals, birds) and its availability, and host species overlap. Also, a geographic break between possible host species during the Pleistocene, domestication of animals and climatic conditions in the region played a role on the genetic structure of H. rufipes. / AFRIKAANSE OPSOMMING: Die suider Afrikaanse bosluise, Amblyomma hebraeum en Hyalomma rufipes is die hoof vektore van Hartwater in diere en Crimean Kongo Haemorargiese koors in mense. Om die filogeografiese struktuur van hierdie ektoparasiete te ondersoek, is bevolking-genetiese studies uitgevoer in suidelike Afrika asook gedeeltelik in oos Afrika. Deur die vlakke van genetiese diversiteit en bevolkingsverbindings regdeur die spesies se natuurlike verspreiding te weet, sal dit dalk moontlik wees om: beheermaatreëls (byvoorbeeld oorgrens) in te stel, die waarskynlikheid van weerstandbiedendheid in nuut losgelate gebiede te verstaan, en meer insigte in die vektoriale kapasiteit te verkry. Mitochondriale sitochroom oksidae (COI) en die interne transkriberende spasieerder 2 (ITS- 2) basisnukleotiedopeenvolgings van elf bevolkings is versamel. Haplotiepe netwerke en molekulêre diversiteitwaardes het in die algemeen, betekenisvolle genetiese verkille tussen meeste van die versamelde bevolkings aangetoon. Fu’s Fs en gemiste-paringverspreidings het voorgestel dat die bevolkings onlangs uitgebrei het nadat hulle 'n bottelnek ondergaan het. 'n Mantel regressie analise het ook betekenisvolle isolasie met afstand aangetoon vir H. rufipes. As die twee spesies vergelyk word het H. rufipes baie sterker seine van genetiese geografiese bevolkingstruktuur gewys as A. hebraeum. 'n Enkele taksonomiese eenheid word voorgestel vir A. hebraeum terwyl H. rufipes gekarakteriseer word deur ten minste drie taksonomiese eenhede. Die verskil tussen die twee spesies kan moontlik verklaar word deur geen-vloeibeperkings in die gebied, die aantal gasheer spesies wat benodig word om die lewenssiklus te voltooi (2 of 3 gashere onderskeidelik), tipe gasheer (domestikeerd- of wildlewend; klein of groot soogdiere, voëls) en hulle beskikbaarheid, en die gasheerspesies se oorvleueling. Dit is ook moontlik dat 'n geografiese breek tussen moontlike gasheerspesies gedurende die Pleistoseen, domestikering van diere en klimaatstoestande in die streek 'n rol kon speel by die genetiese struktuur van H. rufipes. / The NRF and the University of Stellenbosch for funding and bursary

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The Problem.- Retail trade is larger in some cities of smaller population than in others of a greater population. Wealth, which indicates purchasing power, seems to play some part in directing the pattern of retail trade in different cities. An investigator wishing to find whether the retail market is over- or under-developed in a city or group of cities may find that, although the population is slightly smaller than in a similar city, indications of wealth are sources of a potential purchasing power greater than that of a city with a larger population. He must consult authorities who have studied similar problems scientifically or work out some method of determining which city to select as a potential market for development. He will find some statements by marketing experts concerning the part played by population and wealth, but in general he will find that available works contain vague, conflicting, or indefinite statements concerning the tendency of retail trade to follow population or wealth without many scientific attempts being made to evaluate these factors and prove these statements. The present study, working on the hypothesis that of the two, population and wealth (purchasing power), one exerts a greater influence on retail trade than the other. To test this hypothesis, this investigation makes use of correlation techniques. Specifically, since the value of a study of this nature would be lessened by attempting to generalize about all parts of the United States, we shall select southeastern cities which are similar to those in Georgia. Next, we shall select a trade which is not affected to a great extent by purchasers from outside the limits of the city. Finally, we shall classify all factors under the headings of trade, population, and purchasing power. Importance of the Problem.- If the analysis shows that either population or wealth is relatively more important than the other, it should be possible to make some generalizations about trade in urban Georgia and in similar southeastern cities. This study may add to the slowly accumulating knowledge of markets which is assuming more and more the aspects of an accurate science. The business census of 1930 first gave the United States and its research workers something more definite than the guesses and estimates with which they were forced to work in former years. Method of Procedure and Data.- The factors relating to population and weal.th are selected by logical methods. We shall make use of factors which have been found to be associated with trade by other investigators, and shall employ the data which are available for 1929. The year 1929 is selected because it is the only year for which accurate data are available on population, retail trade, and income factors. The censuses of business taken in 1933 and 1935 are forced to estimate population, since an accurate count of population is taken only every ten years. The cities, representative of Georgia urban areas, are selected by arranging all states in the Southeast, as defined by Odum a.nd Moore, 1 according to rank in income per capita in non-farm centers. The states selected are Tennessee, Mississippi, Georgia, Florida, and Virginia. The cities are above 30,000 in population. The information on cities with smaller population is too meager to allow the factors to be classified and studied. To measure wealth, we construct an index of purchasing power composed of the most potent factors relating to income properly weighted. This index will be correlated with the population data, estimates of relative importance arrived at, analyzed, classified, and used as the basis for the conclusions of this study. All available models of such a study are analyzed, and their conclusions are compared with conclusions reached in this study. There are limitations to such a study. Many complex factors are hard to measure, such as location, transportation facilities, and competition, which are not taken into account. This is partly overcome by selecting cities which are in the Southeast and which are similar to cities in Georgia in respect of per capita personal income. Selecting a trade not affected by external trade to a great extent should overcome the difficulty caused by rural trade flowing into cities for shopping goods. The data consist of statistics gathered by governmental and business agencies1 for the period of 1929. Summary of Work by Other Investigators.- There is a. relative scarcity of work on problems of this type for at least two reasons: (1) the methods of multiple correlation are relatively new, and only recently scatter diagrams and other graphic devices have been used to reduce the tremendous amount of mathematical work involved; (2) data on business end economic features of the United States have only become available since the first census of retail distribution was taken in 1929 by the United States Bureau of the Census in that year and in 1933 and 1935. For this reason it is difficult to secure data which could be used to construct an index of purchasing power. A number of studies have been made of the effect of out-of-town trade on urban trade and location of stores within cities, but few of these studies have made use of multiple correlation or purchasing power indexes. The following summary illustrates the difficulties encountered in trying to find a general agreement among authorities on the relative influence of wealth and population. Converse and Mitchell feel that larger towns attract more trade than smaller towns. Dr. Margaret G. Reid states that retail activity and centers increase with the population of the community. The U.S. Bureau of the Census stresses the influence of population on wholesale trade and finds a correlation of .84 with population by the rank data method. J. M. Cassels finds that retail trade is concentrated where population is most dense and where consumers have less opportunity to be self-supporting. Inez K. Rolph concludes that population is the more important factor influencing intra-city trade. 5 This group of authorities stresses population. The following group emphasizes wealth or purchasing power. Lawrence B. Mann finds income and banking resources are more important than population. Dr. Ennna Winslow emphasizes the importance of purchasing power in the study of consumer markets and recommends the construction of a statistical index of purchasing power. Riggleman and Frisbee recognize population's importance but lean heavily toward purchasing power as the vital factor in a market. Eaton Van Wert Read stresses purchasing power and likens shopping dollars to magnetized particles drawn more by shopping goods and less by convenience goods. He employs simple, partial, and multiple correlation. John A. Pfanner, Jr. minimizes population and uses multiple and simple correlation as well as scatter diagrams to test twenty four variables connected with wealth.