966 resultados para Predatory mites


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A new caeculid species Andocaeculus caioi sp. nov. is described from Pampa biome in south Brazil. The species of this family are usually large and strong sclerotized mites with robust and spinulose legs I and II. Until now records of species for South America were known only from Chile and Argentina.

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This paper aims to account for varying economic performances and political stability under dictatorship. We argue that economic welfare and social order are the contemporary relevant factors of political regimes' stability. Societies with low natural level of social order tend to tolerate predatory behavior from dictators in exchange of a provision of civil peace. The fear of anarchy may explain why populations are locked in the worst dictatorships. In contrast, in societies enjoying a relative natural civil peace, dictatorship is less likely to be predatory because low economic welfare may destabilize it.

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Treball de recerca realitzat per un grup d’alumnes d’ensenyament secundari i guardonat amb un Premi CIRIT per fomentar l'esperit científic del Jovent l’any 2006."Tristany i Isolda" representa un dels grans mites eròtics moderns. A través de les diferents versions de les fonts medievals i de les més contemporànies més estimades per melòmans, Wagner i Bédier, es defineixen semblances i diferències i els trets principals dels personatges, arguments, espais... L'estudi d'aquestes obres constata que la finalitat de tots els creadors era, almenys a efectes interpretatius, la mateixa. És evident que tant Tomàs com Wagner intentaven plasmar les alegries i els sofriments dels eterns amants, però potser per influència de Plató mostren un procés catàrtic i redemptor de dos individus a través de l'amor que es converteix en una via cap a un eixamplament tan enorme de la consciència que no pot desembocar sinó en la mort, el punt en què dos amants es converteixen en un únic alè, el punt en què dos éssers satisfacin individualment els seus anhels de felicitat col•lectiva. Partint d'aquesta idea, com el lector comprovarà a les conclusions, es pot sostenir la tesi que aquest tipus de relació en què l'anhel de saviesa vital és tan exacerbat es correspon generalment amb una actitud lesbiana. I és que, perifrasejant Wagner, tot rau en aprendre a morir.

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Aquest treball es va realitzar per a l’assignatura Campus “Olimpisme, Esport i Societat” durant el curs 1996-97 amb l’objectiu de plantejar un possible marc teòric a partir del qual pot contemplar-se el fenomen de l’Olimpisme com a institució amb uns mites fundadors que el legitimen i uns mecanismes de preservació.

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The female, male genital apparatus and larva of Ocyptamus sativus are described. A short report of the predatory habits of this species is made.

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Characterization of sub-classe Acari of importance in Agronomy, Veterinary and Medical Parasitology, based on morphology, behavior and environment of allergenic and parasitc species. Keys for the identification of the six families of Psoroptoidea, chiefly of Pyroglyphidae, starting from which various aspects of the acari of domectic dust and their allergenic behavior are studied.

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In vivo flushing of the ear canals with 50 to 100 ml collected all larvae in 100% of infested cattle. All adult mites were collected from 22 ou 27 parasitized ears (81.5%). Both stages adult and larva were collected from 18 out 22 parasitized ears (82%). The technique is adequate as a measure of prevalence, incidence, density/intensity of infestation as well as in vivo diagnosis. No damage to the host ear has been noticed.

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The question of why some social systems have evolved close inbreeding is particularly intriguing given expected short- and long-term negative effects of this breeding system. Using social spiders as a case study, we quantitatively show that the potential costs of avoiding inbreeding through dispersal and solitary living could have outweighed the costs of inbreeding depression in the origin of inbred spider sociality. We further review the evidence that despite being favored in the short term, inbred spider sociality may constitute in the long run an evolutionary dead end. We also review other cases, such as the naked mole rats and some bark and ambrosia beetles, mites, psocids, thrips, parasitic ants, and termites, in which inbreeding and sociality are associated and the evidence for and against this breeding system being, in general, an evolutionary dead end.

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La preservació digital de la que parla la nostra literatura professional està plena de mites que pensem que s'han d'anar tombant un darrera l'altre, en aquesta presentació us els mencionarem.

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SUMMARY : The coevolution between two intimately associated organisms, like host and parasite, is a widely investigated theme in evolutionary biology. Recently, the use of genetic data in the study of host-parasite systems evidences that the genetic information from some parasites can complement genetic data from their hosts and thus may help to better understand their host's evolutionary history. Phylogenetic and population genetic aspects of bat parasites have been poorly investigated. Spinturnicid mites are highly specialized ectoparasites, exclusively associated with bats and therefore represent an ideal model to extant our knowledge on bat and parasite biology and on their coevolutionary history. In this thesis, I developed several molecular markers (mitochondrial DNA) to compare the genetic patterns of Spinturnix mites with their bat hosts at different levels. The molecular co-phylogeny between Spinturnix sp. and their bat hosts suggests a partial cospeciation and the occurrence of failure to speciate events and multiple host switches. Thus, Spinturnix mites do not exactly mirror the phylogenetic pattern of their hosts, despite their intimate association. Similar roosting habits of the hosts seem to promote host switches between different species, as far as ecological conditions are favourable. The phylogeographic study of the Maghrebian bat M. punicus in the Mediterranean area confirms the presence of M. punicus in North Africa, Corsica and Sardinia and highlights that islands and mainland are genetically highly divergent. The comparison between the parasitic mite S. myoti and the Maghrebian bat suggests that the phylogeographic pattern of the mite is moulded by its host, with open water as main barrier for host and parasite dispersal. Moreover, the unique presence of a European S. myoti lineage on M. punicus from Corsica strongly suggests the former presence of mouse-eared bats (M. myotis and/or M. blythii) in Corsica. By highlighting the probable presence of a nowadays locally extinct host species, S. myoti may represent a good proxy for inferring complex evolutionary history of bat hosts. Finally, population genetic surveys of S. myoti and S. bechsteinii suggest that these mites benefit from close contacts between individuals during the mating season and/or hibernation to disperse among remote colonies. The contrasted genetic patterns of these two distinct bat-mite systems evidence that bat social structure is a determinant factor of the genetic structure of mite populations. Altogether, this PhD thesis demonstrates the usefulness of parasites to gather information about their bat hosts. In addition, my results illustrate how different ecological and biological characteristics of bat species allow the emergence of a surprising diversity in the genetic patterns of the parasites, which may contribute to the diversification and speciation of parasites. RESUME : La co-évolution entre deux organismes intimement liés, comme un parasite et son hôte, fait partie des questions largement étudiées en biologie évolutive. Récemment, l'utilisation de données génétique dans l'étude des interactions hôte-parasite a montré que l'information génétique de certains parasites peut compléter les données génétiques de l'hôte et ainsi peut éclairer l'histoire évolutive de leur hôte. Très peu études ont étudié les interactions entre les chauves-souris et leurs parasites d'un point de vue moléculaire. Les acariens du genre Spinturnix sont des ectoparasites très spécialisés exclusivement associés aux chauves-souris. Ils représentent donc un model idéal pour élargir nos connaissances tant sur l'écologie des parasites de chauves-souris que sur leur coévolution. Durant cette thèse, plusieurs marqueurs moléculaires (ADN mitochondrial) ont été développés pour ainsi comparer la distribution de la variation génétique des parasites du genre Spinturnix avec celle de leurs hôtes, et ceci à différents niveaux. Tout d'abord, la co-phylogénie moléculaire entre les espèces de Spinturnix et les leurs hôtes révèle une co-spéciation partielle ainsi que la présence d'événement de non spéciation et de transferts horizontaux. Ces parasites ne reflètent donc pas entièrement l'histoire évolutive de leurs hôtes, malgré leurs intimes associations. La cohabitation de plusieurs espèces de chauves-souris dans un même gîte permet aux parasites un transfert entre différentes espèces, atténuant ainsi leur degré de co-spéciation. Deuxièmement, l'étude phylogéographique du marin du Maghreb dans le bassin Méditerranéen confirme sa présence en Afrique du Nord, en Corse et en Sardaigne. La comparaison avec un de ses parasites S. myoti suggère que la répartition génétique de S. myoti est façonnée par celle de leurs hôtes, avec les étendues d'eau comme barrière principale tant à la dispersion de l'hôte que de son parasite. De plus, la présence unique d'une lignée européenne de ces parasites sur des marins du Maghreb de Corse suggère fortement la présence du grand ou petit marin en Corse dans le passé. En reflétant la présence potentielle à un endroit donné d'une espèce de chauve-souris actuellement disparue, S. myoti peut représenter une bonne alternative pour comprendre l'histoire évolutive complexe des chauves-souris. Finalement, l'étude des structures génétiques des populations des parasites S. myoti et S. bechsteinii suggère que les contacts corporels entre chauves-souris durant la saison de reproduction ou l'hibernation peuvent permettre la dispersion des parasites entre des colonies éloignées géographiquement. La différence de structure génétique entre ces deux associations particulières montre que la structure génétique des populations de parasites dépend fortement des traits d'histoire de vie de son hôte. Dans l'ensemble, cette thèse démontre l'importance des parasites pour amener des informations sur leurs hôtes, les chauves-souris. Elle illustre aussi comment les différences écologique et biologique des différentes espèces de chauves-souris peuvent amener une étonnante diversité de structure génétique au sein de populations de parasites, ce qui peut peut-être contribuer à la diversification et à la spéciation des parasites.

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This paper compares the predation pressure that ducks and chickens exert on triatomines. For the tests, these birds were placed in individual boxes together with a known number of Triatoma infestans and left to interact from 6 p.m. till the next morning, involving a long lasting period of complete darkness limited by two short-term periods of semi-darkness. There was a shelter which could prevent the bugs from being predated. The number of live and dead triatomines was recorded, considering missing bugs as predated by the birds. Ducks exhibited a greater predatory activity than chickens, that could be due to a long term active period at night while chickens sleep motionless from sunset to dawn. Surviving triatomines that had fed on chickens outnumbered those fed on ducks suggesting that these were less accessible to the triatomine biting. If ducks are better than chickens to detect and eat bugs and to interfere with their feeding in the field, an increase in duck number might help to diminish triatomine density. Further research is needed to determine the feasibility of application of these experimental results.

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L'objectiu de l'aquest treball és definir el fenomen de la violència de gènere i la situació de la dona enfront del mateix. En primer lloc, es defineix la violència de gènere i s'expliquen els diferents tipus de violència. En segon lloc es defineixen diferents teories que expliquen aquest tipus de conductes. A continuació s'esmenten alguns mites o estereotips que existeixen en la nostra societat i s'expliquen possibles perfils de la víctima i de l'agressor. En tercer lloc veurem els factors de risc de patir aquest tipus de violència. Després ens centrarem en les repercussions més significatives que pateixen les dones a causa d'aquest fenomen, i intentarem pensar en els motius que té la dona per seguir en aquesta situació i seguir aguantant aquest tipus de conductes. En cinquè lloc esmentarem algunes pautes per al tractament i la prevenció d'aquesta situació, i finalment esmentarem la llei de violència de gènere per la qual ens regim actualment i els recursos que té la víctima.

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Sixteen species of ectoparasites were collected from 50 wild rodents, from August 1990 to August 1991, in an area of Araucaria augustifolia forest, in the municipality of Tijucas do Sul, State of Paraná, Brazil. Ectoparasites infested 98% of the rodents, with the highest indices of infestation found in the dry-cool season. Species that occurred in single or multiple infestations were recorded. Ectoparasite/host associations were significant (p<0.01) for Gigantolaelaps wolffsohni/Oryzomys nigripes, Polygenis pradoi/Oxymycterus sp. and Amblyopinus sp./Oxymycterus sp. The following represent new host records: Polygenis (Polygenis) tripus from Akodon serrensis and Hoplopleura sciuricola from Sciurus aestuans. New geographic records are given for two species of flea and one sucking lice.

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Mites collected from the auditory canal of Cebus apella (capuchin monkey), family Cebidae, were identified as Fonsecalges johnjadini (Psoroptidae, Cebalginae). It is the first record of this parasite from this monkey. This paper emphasizes the importance of clinical and anatomopathological examinations for parasitic diagnosis in wild animals.