Estudos recentes demonstraram a existência de Rickettsia felis, riquétsia do Grupo da Febre Maculosa, em sangue de pacientes com quadro clínico compatível com a doença e em pulgas infectadas. Este projeto visa determinar a prevalência de R. felis em vetores (pulgas e carrapatos) e em potenciais reservatórios (gambás, cães, gatos, eqüinos e humanos), procedentes de áreas endêmicas (Mogi das Cruzes, Pedreira, Piracicaba e São Paulo), e não endêmicas (Pirassununga) para FM no Estado de São Paulo. Foram utilizados métodos moleculares (reação em cadeia pela polimerase e sequenciamento de DNA), diagnóstico sorológico e cultivo celular. Em gambás capturados (Didelphis aurita e Didelphis albiventris) foram colhidas 312 pulgas, pertencentes às Famílias Pulicidae (141), Rhopalopsyllidae (170) e Ctenophthalmidae (1) e 709 carrapatos (Amblyomma spp e Ixodes loricatus). Nos cães foram colhidos 212 pulgas (Ctenocephalides felis felis) e 115 carrapatos (Amblyomma cajennense, Amblyomma aureolatum e Rhipicephalus sanguineus). Nos gatos foram colhidos 66 pulgas (59 C. felis felis e 7 Rhopalopsyllus lutzi lutzi) e 10 carrapatos (R. sanguineus e Amblyomma spp). A colheita de sangue foi realizada em 94 gambás, 55 cães, 25 gatos, 85 eqüinos e 238 humanos. Rickettsia felis foi detectada em 42-45,8% das pulgas C. felis felis de gambás, cães e gatos; em 4% das pulgas Polygenis (N) atopus de gambás e em 1,8% e 0,7% de carrapatos I. loricatus e Amblyomma spp, respectivamente, colhidos de gambás. Rickettsia bellii foi detectada em carrapatos I. loricatus (59,1%), A. dubitatum (8,7%) e Amblyomma spp (0,9%) e em uma pulga P. (N.) atopus (1%). Não foi possível a detecção de infecção por Rickettsia spp em sangue dos animais e humanos. Contudo, constatou-se presença anticorpos frente aos antígenos de Rickettsia rickettsii, Rickttesia parkeri, R. felis e R. bellii nas áreas estudadas. A titulação obtida sugere infecção por R. rickettsii em gambás, cães, eqüinos e humanos e por R. parkeri em gambás, cães e eqüinos. R. felis e R. bellii foram isoladas e cultivadas com a utilização de células C6/36 e VERO, respectivamente. / Recent studies have showed the presence of Rickettsia felis, a spotted fever group Rickettsiae, in human blood with clinical signs compatible with spotted fever and in infected fleas. This work aims to determine the prevalence of R. felis in potential vectors (fleas and ticks) and reservoirs (opossums, dogs, cats, equines and humans) from endemic (Mogi das Cruzes, Pedreira, Piracicaba e São Paulo), and non-endemic (Pirassununga) areas for spotted fever in the State of São Paulo. Molecular probes (polimerase chain reaction and DNA sequencing), serologic diagnoses and cell culture were used. From trapped opossums (Didelphis aurita and Didelphis albiventris) a total of 312 fleas, belonging to Family Pulicidae (141), Rhopalopsyllidae (170) and Ctenophthalmidae (1) and 709 ticks (Amblyomma spp and Ixodes loricatus) were collected. On dogs a total of 212 fleas (Ctenocephalides felis felis) and 115 ticks (Amblyomma cajennense, Amblyomma aureolatum and Rhipicephalus sanguineus) were collected. On cats, 66 fleas (59 C. felis felis and 7 Rhopalopsyllus lutzi lutzi) and 10 ticks (R. sanguineus and Amblyomma spp) were collected. Blood samples were collected from 94 opossums, 55 dogs, 25 cats, 85 equines and 238 humans. Rickettsia felis was detected in 42-45,8% of the C. felis felis collected on opossums, dogs and cats. This same Rickettsia species was detected in 4% of Polygenis (N.) atopus fleas, and 1,8% and 0,7% of I. loricatus and Amblyomma spp ticks, respectively, collected from opossums. Rickettsia bellii was found in ticks I. loricatus (59,1%), A. dubitatum (8,7%) and Amblyomma spp (0,9%) and in a flea P. (N.) atopus (1%). No Rickettsia DNA was detected in animal or human blood samples. However antibodies against Rickettsia rickettsii, Rickettsia parkeri, R. felis and R. bellii were detected in all locations. The titers suggest infection by R. rickettsii in opossums, dogs, equines and humans and by R. parkeri in opossums, dogs and equines. R. felis and R. bellii were isolated and cultivated with the C6/36 and VERO cells, respectively.

Host-parasite interactions are complex, involving host behaviour, host condition, and possible antagonism or mutualism between co-occurring parasites. The white-footed mouse (Peromyscus leucopus) is a small, abundant, generalist rodent, and the primary host for the black-legged tick (Ixodes scapularis) in its larval stage. Since larval ticks do not actively pursue their hosts (they wait for possible hosts to come to them), individual differences in mouse exploratory behaviour might be expected to correlate with tick burden. However, mice may also prevent tick attachment with defensive behaviour such as grooming. Yet, the relationships between tick parasitism and host exploratory and grooming behaviours have never been assessed. I analysed data from a capture-mark-recapture study conducted over 5 summers (2016-2020) in eastern Ontario, Canada, in which 1,035 mice were captured a total of 4,333 times. The probability of tick parasitism occurring and being more intense was significantly higher when the mouse was also parasitized by fleas, suggesting co-occurrence of these two parasites on host mice. A total of 510 mice were subjected to an open-field test to quantify exploratory and grooming behaviours. Exploration had a negative relationship with tick presence and a positive relation with flea presence. Most interestingly, there was a significant “tick × flea” interaction on exploratory behaviour such that fleas were positively associated with exploration only when ticks were absent. Surprisingly, there was no relationship between grooming behaviour in the open-field test and parasite presence, although grooming increased with mouse activity. This study shows that co-occurring parasite species (ticks and fleas) may interact to affect their host’s exploratory behaviour. Alternatively, individual differences in exploratory behaviour of hosts may differentially affect their susceptibility to being infested with ticks, fleas, or both. Future manipulative studies should use experimental design to determine the causality of the parasitism-behaviour relationships observed.

Flea beetles (Alticini) are a highly diversified group of leaf beetles (Chrysomelidae) with about 8 000 known species from about 560 genera distributed worldwide except Antarctica. The major life strategy of flea beetles is external feeding on vascular plants, similarly to other leaf beetles. However, studies published during last years revealed existence of numerous different flea beetle genera feeding on mosses. Moss-inhabiting flea beetles are usually highly specialized and share similar morphological characteristics, including flightlessness, compact body shape and modified antennae. However, their phylogenetic position remained unknown. In this study, I performed a phylogenetic analysis of 14 known moss- and leaf litter inhabiting flea beetle genera, included into a large dataset of various genera of flea beetles. I sequenced 2 mitochondrial and 2 nuclear genes previously used for phylogenetic analyses of Alticini. I also added numerous Neotropical external feeding alticine genera, because taxon samples from previous studies (Ge et al. 2012; Nie et al. 2017) consisted mainly of Oriental genera. Although deep divergences and phylogenetic positions of several genera were not resolved, the analysis revealed a multiple origin of moss- and leaf litter inhabitance among flea beetles. The morphologically...

The focus of contemporary warfare studies has mainly been on the art of maneuver warfare. However, research has shown that attrition could be a plausible alternative when one part is unable to achieve a decisive victory. To survey the feasibility of deterrence by attrition, this thesis will apply a theory of guerilla warfare on the asymmetrical conflict of the winter war between Finland and the Soviet Union (1939-1940), to explore if the relativity of casualties between the nations could be explained by implementing aspects of guerilla warfare. Robert Taber compiles three guerilla warfare strategists in his book The war of the flea. In this thesis, these three theories are developed and adjusted to exclude revolutionary aspects, thereby focusing on the tactical dimension of guerilla warfare. This study concludes that the finnish tactics attained many of the indicators of guerilla warfare, and that the usage of guerilla warfare had impacted the number of casualties. It is however problematic to draw any conclusion about achieving deterrence by utilizing attrition, as the potential cost of the operation and willingness to accept it is in the eyes of the opponent.

No description available.

Systena frontalis (F.) (Coleoptera: Chrysomelidae), the red headed flea beetle (RHFB), is a ubiquitous pest of ornamental nursery crops in the eastern United States. Defoliation by adults renders plants unsaleable. Control costs and economic losses from injured plants have become a top concern among Virginia nurseries in the past decade. Current management tactics include spraying insecticides up to three times a week during the adult active season. The frequent use of insecticides poses a risk to the environment, non-target organisms, and evolution of resistance within the targeted beetle population. To develop a sustainable pest management program, more information is needed to understand pest biology, quantify the injury potential, and explore control tactics. Methods to monitor this beetle were used to observe peak activity throughout the growing season as well as the adult daily activity levels. There were three observed generations with population peaks in late June, late July, and late August into early September. Within the scale of one day, adult beetles were found to be diurnal with peaks in activity in the middle of the day. These findings will inform growers of the most efficient times to scout and spray, ultimately reducing insecticide usage. Quantification of feeding damage to individual leaves, the entire plant, and preference between older and newer growth may relate plant injury with specific population densities. The use of phenyl ethyl alcohol as an attractant lure, was explored to bolster pest control. Finally, insecticide bioassays were performed to compare those currently used to others yet untested. / Master of Science in Life Sciences / The red headed flea beetle (RHFB) is an important pest of ornamental crops in open-field nurseries along the Eastern United States. Defoliation caused by adult feeding renders plants unsellable. Japanese hollies, hydrangeas, and sweetspire iteas are among the most affected plants. Infested nurseries suffer severe economic losses due to insecticide costs and plant inventory reductions. Growers are spraying insecticides up to three times a week to manage RHFB. Frequent use of insecticides poses risks to the environment non-target organisms. This study will help improve control tactics for this pest and potentially minimize non-target effects by reducing insecticide usage. Understanding when beetles are active throughout the day, and throughout the growing season, may inform timing of scouting and insecticide sprays to maximize effectiveness. With populations highest in late June, late July, and late August, RHFB is estimated to have three generations per year. Adults are most active in the middle of the day and sedentary at night. It was observed how different densities of beetles cause injury to individual leaves and entire plants, and compared feeding preference on older versus newer growth. Chemical control tactics were explored including insecticides labeled and not labeled for RHFB such as iscycloseram. Finally, the effectiveness of phenyl ethyl alcohol as an attractant lure for RHFB was assessed and found ineffective within the open-field nursery ecosystem.

The tobacco flea beetle is one of the major insect pests of tobacco in Virginia. The adult injures the plants by eating small irregular holes in the leaves and the larva by feeding on the roots of the plants. The tobacco flea beetle hibernates in the adult stage in leaves and trash around the edge of tobacco fields and also under trash in the tobacco field, especially around the old tobacco stumps of the previous season. More beetles survived the winter in the soil around the base of the tobacco stumps than in the organic material around these stumps. During the spring of 1938 the tobacco flea beetles emerged from hibernation at Chatham, Virginia, over a period of 70 days. The eggs of the tobacco flea beetle are normally deposited in cracks or small depressions in the soil near the base of its food plant. A female of the overwintering brood deposited 154 eggs during her oviposition period of 53 days. The number of eggs deposited by the later broods were much less and the oviposition period shorter. In the early spring at Chatham, Virginia, the average incubation period for eggs was about 10.5 days, whereas in midsummer eggs generally hatched in from 4 to 7 days. The eggs require a certain amount of moisture for incubation. The larva molted its skin three times. The larva is subterranean in habit and feeds on the roots of the tobacco plant and other plants of the family Solanaceae. The stems of young succulent food plants are often injured by larvae in the second and third instars. Larval records indicate that the larval period may vary from a maximum of 44 days in the early spring to a minimum of 15 days in midsummer. The length of the prepupal period ranged from 1 to 6 days. The pupal stage is passed within an oval shaped earthen cell which is formed by the nature larva. It is usually found about an inch below the surface of the soil. The duration of the pupal period ranged from a maximum of 15 days in the spring to a minimum of 3 days in midsummer. In the fall the pupal period ranged from a minimum of 10 days to a maximum of 16 days. Newly emerged tobacco flea beetles, which are lighter in color than the beetles of the older breed, confine their feeding to the lower leaves which are near the ground. After a few days they spread to other parts of the plant. The preoviposition period for the seasonal broods were as follows: Overwintering brood, 14 days; first brood, 7.5 days; second brood, 7 days; third brood, 9 to 11 days. No eggs were deposited by females of the fourth brood. The tobacco flea beetle deposits very few eggs on air-dry soil as compared with egg deposition on moist soil. The average length of life of individuals of the overwintering brood under caged conditions was approximately 57 days and for the first brood about 53 days. Tobacco is the favorite food plant of the tobacco flea beetle, put other plants of the family Solanaceae are attacked also. The overwintering generation and two later generations of the tobacco flea beetle attacked the tobacco in the field in Pittsylvania County during the season of 1938. There were probably two later broods which were not well defined on suckers during the latter part of the summer and early fall. The tobacco flea beetle was found to be attacked in the adult stage by a hymenopterous parasite; family Braconidae, species Microstonus epitricis (Vier.) The following cultural practices are important in preventing the spread of the tobacco flea beetle: Location of the plant bed, destruction of the plant bed after the plants are set, destruction of suckers, and fall and winter plowing. / Master of Science

A study of the host plants of the tobacco flea beetle was made in Pittsylvania County from April 1 to September 23, 1939. The work was divided into field observations, rearing experiments end population studies. From field observations made throughout the season it was found that this insect fed mostly on the solanaceous plants. especially tobacco. In the spring before the tobacco was transplanted and in the late summer after the harvesting of the crop, the flea beetle fed on a wide variety or plants. Rearing experiments were made using 29 plant species representing 11 families most of which were known as hosts of the adult beetle. These were planted in a small plot of land of a common tobacco soi1. Beetles were caged over these for 4 days and records were kept as to the number of adults that developed from the eggs laid. No beetles emerged from any of the non-solanaceous plants, whereas at least a few developed on all the Solanaceae tested. Many more beetles developed on tobacco, potato and jimson weed than on any of the others. For the population studies tobacco flea beetle and solanaoeous weed counts were made in 14 tobacco fields selected for this purpose. Beetle counts were made at weekly intervals from May 26 until the middle of August and were computed to show the average number of beetles per tobacco plant. Weed counts were made in June and September and were computed to show the average number of weeds per 100 square yards. The data indicated that only tobacco in the beds and potato in the field were of importance in building up the early flee beetle infestation of tobacco. / Master of Science

Flea beetles (FB), (Coleoptera: Chrysomelidae), are common pests of cabbage and eggplant, but little is known about the FB populations in Virginia, their impact on yield, or the most effective control methods. This research investigates the FB populations and impact of their feeding injury on cabbage and eggplant in Southwest Virginia, and determines the most efficacious control methods. In Whitethorne, VA, cabbage and eggplant crops were vacuum sampled weekly throughout two summers. Crucifer flea beetle, Phyllotreta cruciferae (Goeze), and striped flea beetle, Phyllotreta striolata Fabr. were found on cabbage; whereas, eggplant flea beetle, Epitrix fucula (Crotch), and the tobacco flea beetle, Epitrix hirtipennis (Melsheimer) were found on eggplant. To evaluate the impact of FB feeding on these plants, insecticides were used to create a range of pest pressure. Flea beetle densities and defoliation was visually assessed weekly and individual plant as well as whole plot yields assessed at harvest. In both crops, as little as 20% defoliation significantly reduced yield, with higher defoliation resulting in lower yield. The efficacy of various insecticides was also evaluated; soil application of the systemic neonicotinoid dinotefuran had the fewest beetles, the least amount of leaf defoliation, and the highest yield in cabbage and eggplant. Lastly, deltamethrin-incorporated mesh row covers were evaluated and shown to provide excellent control of FB compared to an untreated row cover or a control; and comparable to the standard insecticide, dinotefuran. This research helps vegetable growers to better understand the severity of these pests and how to effectively combat them. / MSLFS / Flea beetles are tiny leaf-chewing pests of vegetables, particularly cabbage and eggplant. High populations of FB chewing on leaves can kill plants in early stages of development, and insecticides are the most common defense. Little is known about which FBs are in Virginia, their effect on vegetables grown in the state, or what the best way of controlling these pests. This research investigates FBs to determine the how they affected yield of cabbage and eggplant in Southwest Virginia, as well as determine the best methods for controlling these pests. Cabbage and eggplant were sampled weekly throughout two seasons, and two species were found on cabbage, the crucifer flea beetle and the striped flea beetle, whereas the eggplant flea beetle and the tobacco flea beetle were found on eggplant. To evaluate FB damage on these plants, defoliation of leaves was evaluated then yield was assessed. In both crops as little as 20% defoliation reduced yield, with higher defoliation resulting in lower yield of surviving plants. Various insecticides were evaluated to determine which treatment and application method were the most effective for controlling FB. A soil-applied systemic insecticide, dinotefuran, had the lowest density of beetles, the least amount of leaf defoliation, and the highest yield in cabbage and eggplant. Lastly, insecticide treated mesh row covers were evaluated and shown to be an effective method for controlling flea beetles on these crops. Treated row covers reduced FB numbers and feeding damage on these crops when compared to an untreated row cover. This research can benefit vegetable growers by helping them understand the severity of these pests and by providing effective management strategies to combat them.

Phosphorus is frequently a limiting factor for phytoplankton in freshwater ecosystems, because algae and cyanobacteria are able to incorporate it only in a dissolved inorganic form. Phytoplankton evolved several mechanisms to overcome phosphorus limitation. One of them is the production of extracellular phosphatases. These enzymes are excreted on the surface of cells or released to the environment. They hydrolyze organic molecules containing phosphorus, which can be then incorporated by cells. This mechanism can influence the competitiveness of algae living in environments that are characterised by long-term phosphorus limitation (that is caused e.g. by the effect of low pH). In this study the influence of phosphorus concentration and form on extracellular phosphatase activity under laboratory conditions was investigated. The two experimental strains of the genus Coccomyxa (Chlorophyta) were isolated from acidified localities with different phosphorus availability  Plešné Lake and Hromnické Lake. Extracellular phosphatase activity on a single-cell level was measured using the FLEA technique and fluorescence microscopy. The FLEA technique allows direct visualization of phosphatases on the cell surface by incubating the samples with the artificial substrate ELF® 97 phosphate. Extracellular...