Made available in DSpace on 2014-06-11T19:32:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-10-09Bitstream added on 2014-06-13T20:02:59Z : No. of bitstreams: 1 castro_tmmg_dr_jabo.pdf: 840130 bytes, checksum: 0cdb1be7253f471f413f5af3250d46f2 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os ácaros Cunaxidae são predadores de ácaros fitófagos, outros pequenos artrópodes e nematóides. O objetivo foi conhecer as espécies de Cunaxidae de ocorrência no solo e em plantas de dois ecossistemas naturais do Estado de São Paulo, Cerrado e Mata Atlântica e os aspectos biológicos de uma das espécies coletadas. Estudos sobre a diversidade desse grupo em ecossistemas naturais são importantes como uma informação a mais para justificar a conservação desses ecossistemas e também para uma possível utilização prática desses predadores como agentes de controle biológico de pragas em ecossistemas agrícolas. De um total de 561 espécimes de cunaxídeos, 42 espécies foram estudadas. Dentre essas espécies, 12 eram conhecidas e 30 eram espécies novas para a ciência. Portanto, cerca de 70% da diversidade consistia em espécies novas. Dentre as espécies conhecidas, apenas uma já havia sido constatada no Brasil. Por meio desse estudo, foi possível verificar uma grande diversidade de cunaxídeos em ecossistemas naturais do Estado de São Paulo. Dentre os táxons novos, 3 gêneros novos e 10 espécies novas foram descritos neste estudo. Uma das espécies novas, Cunaxatricha tarsospinosa, encontrada em plantas da vegetação natural (Mata Atlântica) e na cultura da seringueira do Estado do Mato Grosso do Sul e de São Paulo, teve seus aspectos biológicos avaliados quando alimentada com Tenuipalpus heveae. / The Cunaxidae mites are predators of phytophagous mites, other small arthropods and nematodes. The objective was to know the species of Cunaxidae occurring in the soil and on the plants of two natural ecosystems of the State of São Paulo, Cerrado and Atlantic Forest and the biological aspects of one of the species collected. Studies about the diversity of this group in natural ecosystems are important as additional inforrnation to justify the conservation of those ecosystems and for the possible practical use af these predatory mites as biological control agent of pests in agroecosystems. Df a total of 561 specimens of cunaxids, 42 species were studied. Among these species, 12 were known and 30 were new species to science. Therefore, about 70% of the diversity consisted in new species. Among the known species, just one was already known fram Brazil. Trough this study was possible to verify a high diversity of the cunaxid in the natural ecosystems of the State of São Paulo. Among the new taxa found, 3 new genera and 10 new species were described in this study. One of the new species, Cunaxatricha tarsospinosa, found on plants of the natural vegetation (Atlantic Forest) and on the rubber tree plantation of the State of Mato Grosso do Sul and São Paulo, has their biological aspects evaluated when fed with Tenuipalpus heveae.

Orientador: Daniela Carvalho dos Santos / Resumo: Devido ao uso indiscriminado de inseticidas de largo espectro na produção agrícola e a vulnerabilidade dos inimigos naturais a este tipo de exposição, efeitos colaterais podem afetar a função biológica destes inimigos, tornando sua utilização no controle biológico impraticáveis. A busca por pesticidas mais seletivos sobre esses organismos benéficos é necessária, e entre as alternativas, enfatizamos o aumento do uso dos biopesticidas. Um dos biopesticidas amplamente utilizados é o óleo de nim (Azadirachta indica), e sua segurança e compatibilidade com os inimigos naturais têm sido mais esclarecidos através de estudos ecotoxicológicos que verificam os efeitos da exposição indireta através da ingestão de presas contaminadas. Assim, este estudo analisou a resposta das células epiteliais do mesêntero de adultos do crisopídeo Ceraeochrysa claveri quando expostos por ingestão de presa contaminada com óleo de nim durante a fase larval e a ocorrência de efeitos letais e subletais em seu desenvolvimento. Larvas de C. claveri foram alimentadas com ovos de Diatraea saccharalis tratados com óleo de nim nas concentrações de 0,5%, 1% e 2% durante todo período larval. Fêmeas adultas obtidas a partir destes tratamentos foram utilizadas em análises morfológicas e ultraestruturais da resposta celular do mesêntero. Além disso, parâmetros biológicos também foram avaliados durante o desenvolvimento pós-embrionário. O óleo de nim provoca efeitos citotóxicos no mesêntero através de pronunciadas alte... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Due to the indiscriminate use of broad-spectrum insecticides in agricultural production and the vulnerability of natural enemies to this type of pesticide exposure, side effects can affect the biological function of these enemies, making their use for biological control unfeasible. A search for more selective pesticides on these beneficial organisms is necessary, and among the alternatives, we emphasize the increased use of biopesticides. One of the biopesticides widely used is the neem oil (Azadirachta indica), and its safety and compatibility with natural enemies have been more clarified through ecotoxicological studies which check the effects of indirect exposure by intake of poisoned preys. Thus, this study analyzed the response of midgut epithelial cells of adult of lacewing Ceraeochrysa claveri when exposed by intake of contaminated prey with neem oil during the larval stage and the occurrence of lethal and sublethal effects on its development. Larvae of C. claveri were fed on eggs of Diatraea saccharalis treated with neem oil at a concentration of 0.5%, 1% and 2% throughout the larval stage. Adults female obtained from these treatments were used in the morphological and ultrastructural analyses of cellular response of midgut. Moreover, biological parameters were also measured during the post embryonic development. Neem oil causes cytotoxic effects on the midgut through pronounced alterations as cell swollen, loss of integrity of cell cortex, dilated cisternae of the ro... (Complete abstract click electronic access below) / Doutor

Os vertebrados tetrápodes e ectotérmicos possuem a temperatura do corpo variável de acordo com a temperatura do ambiente. Estudos abordando lagartos e serpentes demonstram que diversos comportamentos ou funções dos vertebrados ectotérmicos sofrem direta ou indiretamente influência da temperatura na adequação biológica (fitness) (BARTHOLOMEW, 1982; HUEY, 1982; LILLYWHITE, 1987, MORI; BURGHARDT, 2001). O comportamento antipredatório constitui um caso especial dos comportamentos sabidamente influenciados pela temperatura, pois parece sofrer diversos tipos de alterações em diferentes grupos de tetrápodes ectotérmicos, como salamandras (BRODIE JR.; DUCEY; LEMOS-ESPINAL, 1991), anfíbios anuros (GOMES; BEVIER; NAVAS, 2002), lagartos (RAND, 1964; HERTZ; HUEY; NEVO, 1982; CROWLEY; PIETRUSZKA, 1983) e serpentes (FITCH, 1965; HERCKROTTE,1967; ARNOLD; BENNETT, 1984; SCHIEFFELIN; QUEIROZ, 1991; KEOGH; DESERTO, 1994; MORI; BURGHARDT, 2001). Esses estudos mostram que a temperatura pode afetar as repostas comportamentais tanto em termos de magnitude quanto de qualidade, o que permite supor que as mudanças no tipo de comportamento com a temperatura sejam consistentes com os efeitos da temperatura sobre o desempenho comportamental. O atual estudo testou, mediante uma análise do comportamento, a serpente Tomodon dorsatus (Dipsadidae) em diferentes temperaturas corpóreas, quando exposta a um estímulo externo simulando um ataque predatório. Esta espécie foi escolhida por apresentar um rico repertório defensivo (BIZERRA, 1998). Para as análises, os comportamentos defensivos foram classificados em dois grandes grupos: agressivos e passivos ou de escape, conforme o comportamento apresentado no momento do estímulo. No decorrer do estudo, foi observado que alguns animais eram excessivamente agressivos enquanto que outros eram extremamente propensos à fuga. Por isso, além da classificação inicial, foi feita outra análise que consistiu em classificar os indivíduos em dois grandes grupos: DPA (defesa por agressão) e FCP (defesa via fuga ou comportamento passivo). Neste estudo, observamos que houve uma grande variação individual no que se refere ao comportamento antipredador e essa diferença entre os indivíduos parece ser mais significante quando comparada à variação eventualmente induzida pela temperatura. / Tetrapodes and ecotermicos vertebrates have a variable body temperature according to the temperature of the environment. Studies addressing lizards and snakes show that several behavior and functions of ectotermicos vertebrates suffer directly or indirectly influence of temperature on biological adequacy (fitness) (BARTHOLOMEW, 1982; HUEY, 1982; LILLYWHITE, 1987, MORI; BURGHARDT, 2001). Anti-predatory behavior constitutes a special case among behaviors influenced by temperature, because it seems to suffer from various types of changes in different groups of tetrápodes ectotermicos as salamanders (BRODIE JR.; DUCEY; LEMOS-ESPINAL, 1991), anuros amphibians (GOMES; BEVIER; NAVAS, 2002), lizards (RAND, 1964; HERTZ; HUEY; NEVO, 1982; CROWLEY; PIETRUSZKA, 1983), and snakes (FITCH, 1965; HERCKROTTE,1967; ARNOLD; BENNETT, 1984; SCHIEFFELIN; QUEIROZ, 1991; KEOGH; DESERTO, 1994; MORI; BURGHARDT, 2001).These studies show that the temperature affects behavioral responses both in terms of magnitude and quality, which suggests that the changes on the type of behavior with temperature be consistent with the effects of temperature on the behavioral performance. The current study tested through an analysis of the behavior Tomodon dorsatus snake (Dipsadidae) at different body temperatures when exposed to an external stimulus simulating a predatory attack. This species was chosen because it presents an enriched defensive repertoire (BIZERRA, 1998). For analysis, the defensive behaviors were classified into two main groups: \"aggressive\" and \"passive or escape as the behavior exhibited when the stimulus. During the study, it was observed that some animals were overly aggressive while others were extremely prone to flight. Therefore, besides the initial classification was made a separate analysis was to classify individual in two groups: DPA and FCP. This division that was useful to analyze the influence of temperature in different animals in their degree of aggressiveness. In this study we found that there was great individual variation in relation to antipredator behavior and the difference between individuals appears to be more significant when compared with the variation may be induced by temperature

Translational research provides a unique opportunity to investigate innate and conditioned fear to develop an integrated understanding of anxiety disorders, ultimately improving treatment for those afflicted. Many fear conditioning paradigms use physically aversive stimuli to induce fear but ethological stimuli may better represent psychological disorders from a translational standpoint. Natural predators and immobilization have been successful in inducing both innate and contextually conditioned fear in rodents but an inhibitory avoidance paradigm that uses ethologically relevant stimuli has yet to be developed. To expand the use of these stimuli into inhibitory avoidance conditioning, an inhibitory avoidance paradigm was developed to include a range of ethologically relevant psychologically (predator exposure, physical restraint) and physically aversive stimuli (electric shock). Adult male Sprague-Dawley rats were conditioned using a step-through inhibitory avoidance model to associate crossing between two compartments with the presentation of an aversive stimulus. Subjects were assessed for conditioned fear measured by crossing latency, freezing behavior and defecation during conditioning and a contextual memory test. Freezing behavior within the conditioning chamber remained constant throughout conditioning regardless of stimulus but all groups conditioned with an aversive stimulus showed significant increases in crossing latency both overtime and during the retention test compared to subjects that received no aversive stimulus after crossing, indicating that inhibitory avoidance conditioning was achieved. Significant increases in defecation were also observed for footshock and predator exposed animals and this effect was intensified by predator exposure, but only after repeated exposures. With this, both predator based and restraint-based variations of the inhibitory avoidance model (PBIA and RBIA, respectively) have been successfully established and have been shown to induce evidence of emotionality similar to those seen in traditional shock-based inhibitory avoidance (SBIA) models. Successful development of PBIA and RBIA expands the range of stimuli that can be used with conventional inhibitory avoidance models, allowing for investigation into topics that have yet to be addressed in inhibitory avoidance conditioning.

Worldwide declines in populations of large elasmobranchs and the potential cascading effects on marine ecosystems have garnered considerable attention. Far less appreciated are the potential ecological impacts of changes in abundances of small to medium bodied elasmobranchs mesopredators. Crucial to elucidating the role of these elasmobranchs is an understanding of their habitat use and foraging ecology in pristine conditions. I investigated the trophic interactions and factors driving spatiotemporal variation in abundances of elasmobranch mesopredators in the relatively pristine ecosystem of Shark Bay, Australia. First, I describe the species composition and seasonal habitat use patterns of elasmobranch mesopredator on the sandflats of Shark Bay. Juvenile batoids dominated this diverse community and were extremely abundant in nearshore microhabitats during the warm season. Stomach content analysis and stable isotopic analysis revealed that there is a large degree of dietary overlap between common batoid species. Crustaceans, which tend to be found in seagrass habitats, dominated diets. Despite isotopic differences between many species, overlap in isotopic niche space was high and there was some degree of individual specialization. I then, investigated the importance of abiotic (temperature and water depth) and biotic (prey and predator abundance) factors in shaping batoid habitat use. Batoids were most abundant and tended to rest in shallow nearshore waters when temperatures were high. This pattern coincides with periods of large shark abundance suggesting batoids were seeking refuge from predators rather than selecting optimal temperatures. Finally, I used acoustic telemetry to examine batoid residency and diel use of the sandflats. Individual batoids were present on the sandflats during both the warm and cold seasons and throughout the diel cycle, suggesting lower sandflat densities during the cold season were a result of habitat shifts rather than migration out of Shark Bay. Combined, habitat use and dietary results suggest that batoids have the potential to seasonally impact sandflat dynamics through their presence, although foraging may be limited on the sandflats. Interestingly, my results suggest that elasmobranch mesopredators in pristine ecosystems probably are not regulated by food supply and their habitat use patterns and perhaps ecosystem impacts may be influenced by their predators.

Pharmaceuticals polluting natural environments pose a greater and greater threat in today’s society. Benzodiazepines, the most common form of anxiolytic drug, can commonly be found in nature as a result of the release of human wastewater containing the drug, and have been shown to affect both fish and frog species in several different ways related to predator evasion. This study aims to determine whether a common benzodiazepine, oxazepam, has any inhibitory effect on induced behavioral defenses in the boreal frog species Rana temporaria. Larvae of R. temporaria were exposed to an oxazepam gradient, paired with three different predator regimes consisting of a control, an ambush-predator setting, and a pursuing-predator setting. The larvae were then filmed at three different Gosner stages during simulated predator encounters, while measuring maximum velocity and acceleration, as well as activity- and exploration level, and the duration of avoidance following each encounter. Tail related morphological traits were also measured in order to correlate velocity and acceleration with trait properties. Avoidance duration was found to decrease when exposed to ambush predators, regardless of oxazepam concentration. No other effect of predators could be found during this study, and no significant correlations between tail properties and velocity or acceleration were seen. Oxazepam was not found to inhibit any induced behavioral defenses, nor did it alter any of the examined behavioral traits.

We test the controversial ideas about the role of corridors in fragmented animal habitats. Using simulation studies we analyze how fragmentation affects a simple prey-predator system and how the introduction of openings that connect the habitats changes the situation. Our individual based model consists of 3 levels: renewable prey food, as well as prey and predators that both have a simple economy. We find, in line with intuition, that the fragmentation of a habitat has a strong negative effect especially on the predator population. Connecting the fragmented habitats facilitates predator (and hence prey) survival, but also leads to an important counterintuitive effect: in the presence of a high quality predator, connected fragmented systems fare better in terms of coexistence than do unfragmented systems. Using a frequency domain analysis we explain how corridors between sub-habitats serve as "wave breakers" in the population flow, thus preventing deadly density waves to occur.

Many organisms utilize toxic or noxious compounds as a means of deterring predation. Eastern newts (Notopthalmus viridescens), along with other species in the family Salamandridae, possess a potent neurotoxin called tetrodotoxin (TTX). Although TTX can serve as an effective antipredator mechanism in species of newts with high concentrations (e.g., Taricha), eastern newts have relatively low levels of toxicity in comparison to those species, and it may not serve as an effective antipredator mechanism against all threats. In this case, they may benefit rather by utilizing behavioral changes to avoid initial contact with predators. We tested for predator-avoidance behavior in newts by exposing individuals to kairomones from various predators. We recorded activity patterns of newts when they were exposed to cues from potential predators including bullfrogs (Lithobates catesbeiana), water snakes (Nerodia sipedon) and snapping turtles (Chelydra serpentina), as well as a non-predator (bullfrog tadpoles), and a control (deionized water). Newts reduced activity when exposed to snapping turtle stimuli, but did not change activity when exposed to any other chemical cues. We verified that newts interact with this predator by trapping snapping turtles found in ponds from which newts were collected. Finally, we used turtles caught during this sampling to test whether they are an actual predator of newts and whether newts shift microhabitat use when exposed to this predator. In each replicate, turtles consumed newts, and newts spatially avoided the snapping turtle, relative to a control. The results of these experiments indicate newts rely on predator-avoidance behavior to reduce the probability of being consumed by snapping turtles, but do not reduce activity in response to other potential predators that may only consume them rarely.

Engelmann spruce (Picea engelmannii Parry ex Engelm.) exhibits cone crop periodicity, producing seed in a cyclic pattern. Variation in seed production has been noted between individuals of a population, but synchronization on a large scale is common. The theory that ultimately these periodic large cone crops have resulted from the selective pressures of seed and cone predators, referred to as the predator satiation hypothesis, is considered. Assuming predator pressures have operated over evolutionary time to select for periodic synchrony, associations between seed and cone predators and cone crop production levels were anticipated. These potential consequences of predator satiation were examined. Long-term data from 1948 to 1970 of Engelmann spruce cone production levels and small mammal populations, estimated from trappings, were analyzed for positive associations. Three small mammal categories, mice (Peromyscus spp.), chipmunks (Eutamias spp.) and red squirrels (Tamiasciurus hudsonicus) were examined. Only the correlation coefficient between population indices for mice and cone crop production was found to be significant. Engelmann spruce cones were collected throughout the summer of a year of low cone production. The impacts and timing of insect infestation were determined in developing cones. The major insects found were western spruce budworm (Choristoneura occidentalis (Freeman) (Lepidoptera: Torticidae)), fir coneworm (Dioryctria abietvorella (Grote) (Lepidoptera: Pyralidae)), and spruce seed moth (Laspeyresia youngana (Kearfott) (Lepidoptera: Olethreutidae)). Insects reduced the survival of cones to 11.48 cones out of 100. The high percentage of seeds and cones lost to insect predation supported previous studies of a similar nature. Both studies examined the potential consequences of the predator satiation hypothesis which has been suggested as an adaptive mechanism for trees to avoid seed and cone predation.

The economic effects, to the Utah range-sheep operation and to the economy of the state of Utah, of predation upon sheep were studied by use of a personal interview survey. This survey sampled 20 percent of the range-sheep operations in Utah. The sheep and lamb death loss from predation was found to be 61.0 sheep and lambs per 1,000 head of ewes in fiscal 1969. The survey. also showed that 71.36 percent of the losses were lambs and 28.64 percent were ewes. The total economic·lpss to Utah sheep ranchers was calculated to be 1,062,502 dollars as a result of predation, in fiscal year 1969. Using the Type II multiplier of 4.330 for the livestock industry, published by the University of Utah, the total economic loss, resulting from predation upon sheep and lambs, to all sectors of the economy of the state of Utah, was determined as 3,901,854 dollars The bounty system was found to be the least costly method of controlling predators, followed by private control methods. The Utah District, Division of Wildlife Services, had the highest control cost per predator, and this increased drastically when a change of name and changes in personnel and policies were instituted for this federal predator control agency.