In 1910 C. W. Stiles made the following comment as a part of a summary statement to his extensive study of the stigmatal plates of Dermaeentor ticks: "The specific determination of ticks is attended in many cases with con-siderable difficulty."

Vector control is fundamental to the suppression and/or eradication of many endemic and epidemic diseases affecting man. The discovery and widespread application of insecticides in vector control programs focused early attention on studies revealing ecological and behavioral characteristics of arthropod vectors. As a consequence of this emphasis, few attempts were made to investigate arthropod cytogenetics. However, recent recognition of the deleterious effects of highly persistent insecticides on the environment and the development of insecticide resistance by vectors of human disease have established the importance of cytogenetics as a base on which programs for control of vector populations may be built (Wrigth and Pal, 1967).

Thesis (PhD)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Fleas (Siphonaptera) are obligate ectoparasites of mammals and birds. Due to their economic importance as disease vectors, most contemporary studies on macroparasites now also consider the spatial variation of parasite communities and the underlying mechanisms involved in shaping current distribution patterns. Fleas differ in life history traits, such as the level of host specificity and microhabitat preferences, which can result in differential evolutionary responses to similar abiotic events. The main objectives of this study are to investigate: (1) the influence of vicariance and host association on the genetic structure of two generalist flea species, Listropsylla agrippinae, and Chiastopsylla rossi. The taxa differ in the time spent on the host (fur vs. nest) and the level of host specificity; (2) the taxonomy of Dinopsyllus ellobius to determine whether more than one species exist and if so to then elucidate the mechanisms of speciation; and (3) the influence of flea life history on species distribution model performance and see if the relative importance of predictor variables differ between species with different life histories. A total of 1423 small mammals were brushed to collect 2906 flea individuals originating from 31 geographically distinct localities throughout South Africa (SA). Phylogeographic structure of L. agrippinae and C. rossi were determined by making use of 315 mitochondrial COII (mtDNA) and 174 nuclear EF1-α (nDNA) sequences. The more host specific fur flea, L. agrippinae, displayed pronounced spatial phylogeographic structure, based on mtDNA, which was congruent with host vicariance in the region. In contrast, the more generalist nest flea, C. rossi, showed a higher level of inter-populational divergence, based on mtDNA and nDNA, and this may be attributed to comparatively higher restrictions to dispersal when compared to the more specific fur flea. In an attempt to resolve the taxonomy of D. ellobius, 151 mtDNA and 68 nDNA alleles were generated from individuals meeting the morphological description of D. ellobius. Two distinct D. ellobius lineages that corresponded to previously described species (D. ellobius and D. abaris) were recorded. The results indicate that the two species indeed differ morphologically and based on the distribution of the two species it was concluded that the diversification could be a result of climate driven vicariance and subsequent ecological segregation according to habitat use. Locality records from Segerman (1995) were digitized and used as background data in species distribution modelling. Sufficient information was obtained for 21 flea species. A total of 68 climatic and landscape feature predictor variables were obtained and through a process of elimination, 19 variables were ultimately used. Model performance was good to excellent on average and the contribution of climate and landscape feature variables differed between fleas with different life histories. Historical and contemporary climate has the most prominent effect on flea distribution at the regional scale, but the level of host association influences the phylogeographic pattern of fleas. This study provides the first evidence of congruent phylogeographic patterns between a generalist temporary parasite and its hosts. Our findings provide further support for the notion that more than one species exist within the D. ellobius complex and that speciation is a result of complex interactions. The study also provides novel data on the role of environmental variables in shaping the geographic distribution of flea species with different life histories. With the anticipated rise in flea-borne diseases worldwide, due to changes in vector distribution, the study further emphasize the need for studying the mechanisms involved in shaping flea distribution patterns. / AFRIKAANSE OPSOMMING: Vlooie (Siphonaptera) is verpligte ektoparasiete van soogdiere en voëls. As gevolg van hul ekonomiese belangrikheid as vektore van oordraagbare siektes, neem meeste kontemporêre studies oor makroparasiete nou die ruimtelike variasie (vikariansie) van parasiet gemeenskappe en die onderliggende meganismes betrokke by die vorming van die huidige verspreiding patrone in ag. Vlooie verskil in lewensgeskiedenis eienskappe, soos die graad van gasheer spesifisiteit en mikrohabitat voorkeur, wat kan lei tot differensiële evolusionêre patrone tot soortgelyke abiotiese gebeure. Die belangrikste doelwitte van hierdie studie is om ondersoek in te stel na: (1) die invloed van vikariansie en gasheer assosiasie op die genetiese struktuur van twee algemene vlooi spesies, Listropsylla agrippinae en Chiastopsylla rossi. Die taxa verskil in die hoeveelheid tyd wat gespandeer word op die gasheer (pels vs. nes) en die graad van gasheer spesifisiteit; (2) die taksonomie van Dinopsyllus ellobius om te bepaal of daar meer as een spesie bestaan, en indien wel, die meganismes van spesiasie voortbring; en (3) die invloed van vlooi lewensgeskiedenis op die prestasie van die spesies verspreidings model en kyk of die relatiewe belangrikheid van omgewingsvoorspellers verskil tussen spesies met verskillende lewensgeskiedenisse. 'n Totaal van 1423 klein soogdiere is geborsel om 2906 vlooi individue afkomstig van 31 geografies verskillende plekke in Suid-Afrika in te samel. Filogeografiese struktuur van L. agrippinae en C. rossi is bepaal deur gebruik te maak van 315 mitochondriale COII (mtDNA) en 174 kern EF1-α (nDNA) volgorde bepalings. Die meer gasheer spesifieke pels vlooi, L. agrippinae, het ruimtelike filogeografiese struktuur aangetoon, gebaseer op mtDNA, wat ooreenstem met gasheer vikariansie in die streek. In teenstelling hiermee het die minder gasheer spesifieke nes vlooi, C. rossi, 'n hoër vlak van inter-populasie divergensie getoon, gebaseer op mtDNA en nDNA, wat toegeskryf kan word aan relatief hoër beperkings op verspreiding teenoor die meer gasheer spesifieke pels vlooi. In 'n poging om die taksonomie van D. ellobius op te los is 151 mtDNA en 68 nDNA allele gegenereer uit individue wat voldoen aan die morfologiese beskrywing van D. ellobius. Twee afsonderlike D. ellobius afstammelinge wat ooreengestem het met voorheen beskryfde spesies (D. ellobius en D. abaris) is aangeteken. Die resultate dui daarop dat die twee spesies inderdaad morfologies verskil en gebaseer op die verspreiding van die twee spesies is daar tot die gevolgtrekking gekom dat die diversifikasie moontlik toegeskryf kan word aan klimaat gedryfde vikariansie en daaropvolgende ekologiese segregasie volgens habitat gebruik. Geografiese verspreidings rekords van Segerman (1995) was gedigitaliseerd en gebruik as agtergrond data in die spesie verspreidings modelle. 'n Totaal van 68 klimaat en landskap kenmerk voorspeller veranderlikes is verkry, en deur 'n proses van eliminasie, is 19 veranderlikes gebruik. Model prestasie was oor die algemeen goed tot uitstekend en die bydrae van klimaat en landskaps veranderlikes het verskil tussen vlooie met verskille in lewensgeskiedenis. Historiese en kontemporêre klimaat het die mees prominente effek op vlooi verspreiding by die plaaslike skaal, maar die vlak van die gasheer assosiasie beïnvloed die filogeografiese patroon van vlooie. Hierdie studie bied die eerste getuienis van ooreenstemmende filogeografiese patrone tussen 'n minder gasheer spesifieke, tydelike parasiet en sy gashere. Ons bevindinge bied verdere ondersteuning vir die idee dat meer as een spesie bestaan binne die D. ellobius kompleks en dat spesiasie 'n gevolg is van komplekse interaksies. Die studie bied ook nuwe data oor die bydrae van die omgewingsveranderlikes in die vorming van die geografiese verspreiding van vlooi spesies met verskillende lewensgeskiedenisse. Met die verwagte styging in vlooi-oordraagbare siektes wêreldwyd, as gevolg van veranderinge in vektor verspreiding, beklemtoon die studie verder die noodsaaklikheid vir die bestudering van die meganismes betrokke in die vorming van vlooi verspreiding patrone. / National Research Foundation (NRF)

Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Includes bibliographical references (leaves 201-210). Issued in print and online. Available via ProQuest Digital Dissertations.

Thesis (M.S.)--Georgia Southern University, 2009. / "A thesis submitted to the Graduate Faculty of Georgia Southern University in partial fulfillment of the requirements for the degree Master of Science." Directed by Lance A. Durden. ETD. Includes bibliographical references (p. 17-32) and appendices.

Doctor of Philosophy / Department of Biology / Jack F. Cully, Jr. / Black-tailed prairie dogs (Cynomys ludovicianus) are epizootic hosts for plague (Yersinia pestis); however, alternate enzootic hosts are important for the maintenance of the pathogen. We determined small rodents and prairie dog associations and quantified rodent and flea relationships in the presence and absence of prairie dog colonies and plague. We identified potential alternate hosts and flea vectors for the maintenance and transmission of plague in the prairie ecosystem. This is the first multi-year study to investigate associations between prairie dogs, rodents and fleas across the range of the black-tailed prairie dog. Few rodent species associated with black-tailed prairie dogs and were found to be highly abundant on colonies. Rodent species implicated in plague were present at study areas with and without plague. Peromyscus maniculatus and Onychomus leucogaster, two widely occurring species, were more abundant in areas with a recent history of plague. Flea community characteristics varied within each study area in the presence and absence of prairie dogs. Based on flea diversity on rodents, and the role of rodents and fleas in plague, we identified P. maniculatus and O. leucogaster and their associated fleas, Aetheca wagneri, Malareus telchinus, Orchopeas leucopus, Peromyscopsylla hesperomys, and Pleochaetis exilis to be important for the dynamics of sylvatic plague in our study areas. Peromyscus maniculatus and O. leucogaster were consistently infected with Bartonella spp., another blood parasite. Presence of prairie dog fleas on other rodents at both off and on prairie dog colonies suggests the potential for intra and interspecific transmission of fleas between rodent hosts, and between other small rodents and prairie dogs.

Plague bacteria (Yersinia pestis) are transmitted to susceptible mammals by fleas. At least 25 flea species found in North America have been identified as plague vectors. The most efficient flea vector is the Oriental rat flea Xenopsylla cheopis, while the cat flea Ctenocephalides felis is a poor vector. The factors that determine vector competence of different fleas are not known. The main obstacles that the bacteria must overcome in the flea gut are also unknown. Fleas' molecular responses to Y. pestis invading could be a determining factor to control the bacterial survival and growth. Good and poor vectors might have different gene expression patterns when they are infected with Y. pestis. To investigate this hypothesis, we constructed cDNA libraries of infected fleas (X. cheopis and C. felis) using Suppression Subtractive Hybridization at 1 and 2 days post-infection. The infection approaches were either hemocoel injection or oral infection. We measured expression of several of the genes using quantitative real-time PCR. The results indicated that changes in gene expression were modest. We observed that the route of infection (oral vs. hemocoel injection) had a strong effect on the genes that were upregulated, with hemocoel injection inducing more obvious immune-related genes than oral infection. We also saw that infected X. cheopis has different gene expression patterns than infected C. felis. Several of the genes from both species are predicted to be involved in production and removal of reactive oxygen species (ROS). Consistent with this observation, the levels of peroxide in X. cheopis midguts was higher following oral infection with Y. pestis, than in uninfected fleas, and Y. pestis grew differently in antioxidant-fed fleas, demonstrating that ROS production could be an important defense in fleas early after infection

Much work has been done concerning those parasites found upon the host. Very little has been done concerning those parasites that are parasitic but are very rarely found upon the host. Therefore, the purpose of this study is to determine seasonal distribution of those fleas found in the nests of the desert wood rat (N. l. lepida). This paper shows that there is a seasonal variation of flea populations within a certain geographic area. It also shows that certain species of fleas are distributed seasonally; not all species being present in the same season. Three of the eleven species collected from the nests are plague implicated, being either potential or capable vectors. A number of other nest consortes were found to demonstrate seasonal variations to some extent. Collecting and laboratory methods for the collection and preparation of fleas are discussed.

The purpose of this study was to determine the species of fleas infesting the mammals of the families Cricetidae and Muridae in Utah County. This was accomplished by establishing twelve collecting stations throughout the county from which 198 mammals were collected. From these hosts, 392 fleas were collected representing three families, nineteen genera , and twenty-four species. Four species are new to the State of Utah and twenty-two species are recorded from Utah County for the first time.

A total of 9,936 fleas, representing 27 species, have been processed for study and identified. They were associated with 2,011 small mammals, representing 38 species, collected throughout Morocco from October 12, 1969 to July 20, 1970 by personnel of the Smithsonian Institution. Two species, Synosternus cleopatrae pyramidis (Rothschild and Xenopsylla ramesis (Rothschild), comprised 68 percent of the fleas collected. Two subspecies are described: Ctenophthalmus andorrensis opistolatus, ssp. n. and Ctenophthalmus russulae tangerensis, ssp. n.. There are three ecological subdivisions of Morocco: the coast and coastal plains, the Atlas Mountains, and the pre-saharan desert. Even though there is some overlap, the flea fauna of each subdivision is distinctive. Human plague has occurred most frequently in the coast and coastal plains region where species of Xenopsylla and Nosopsyllus are most abundant. The flea fauna is most diversified in the presaharan region, but the threat of human plague in this region is not great, because of the sparse human population.