960 resultados para predatory mite
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El fascinant mite de Dànae ha inspirat artistes de múltiples disciplines; poetes, escriptors, escultors, gravadors i pintors han quedat subjugats per aquesta història i per la seva ductilitat. En aquest document concentrarem la nostra anàlisi en l'estudi d'un conjunt representatiu i divers de pintures sobre l'escena de la pluja d'or del mite de Dànae.
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Article sobre la desamortització a les comarques gironines
New record of predatory ladybird beetle (Coleoptera, Coccinellidae) feeding on extrafloral nectaries
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New record of predatory ladybird beetle (Coleoptera, Coccinellidae) feeding on extrafloral nectaries. Feeding by Exoplectra miniata (Germar) on extrafloral nectaries of Inga edulis Mart. was observed in Nova Friburgo, Rio de Janeiro, Brazil. This is the first record of this behavior for Exoplectrini.
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Predatory behavior of Pseudodorus clavatus (Diptera, Syrphidae) on aphids tended by ants. In this study, we examined the interactions between myrmecophilous aphids, their ant-guards and a predatory syrphid species, Pseudodorus clavatus (F.). Larvae of this predator were found in the colonies of three aphid species: Aphis gossypii, A. spiraecola and Toxoptera sp., which were tended by eight ant species, especially Camponotus. Hoverfly larvae managed to infiltrate the aphid colonies and consume nymphs. Predator larvae exhibited inconspicuous movements and were not detected by ants which were commonly observed touching and antennating the larvae they come into contact. These results suggest that behavioral and chemical cues are involved in the infiltration and on the successful predation of syrphids upon aphids.
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This work provides a contribution to a better understanding of the trophic ecology of important predators in the Northern Humboldt Current System, the jack mackerel (Trachurus murphyi), the chub mackerel (Scomber japonicus) and the jumbo squid (Dosidicus gigas) by the characterization of the highly variable feeding patterns of these species at different spatiotemporal scales. We provided new knowledge on the comparative trophic behaviour of these species, defined as opportunistic in previous investigations. For that purpose we applied a variety of statistical methods to an extensive dataset of 27,188 non-empty stomachs. We defined the spatial organization of the forage fauna of these predators and documented changes in prey composition according to predators’ size and spatiotemporal features of environment. Our results highligh the key role played by the dissolved oxygen. We also deciphered an important paradox on the jumbo squid diet: why do they hardly forage on the huge anchovy (Engraulis ringens) biomass distributed of coastal Peru? We showed that the shallow oxygen minimum zone present off coastal Peru could hamper the co-occurrence of jumbo squids and anchovies. In addition, we proposed a conceptual model on jumbo squid trophic ecology including the ontogenetic cycle, oxygen and prey availability. Moreover we showed that the trophic behaviour of jack mackerel and chub mackerel is adapted to forage on more accessible species such as for example the squat lobster Pleurocondes monodon and Zoea larvae. Besides, both predators present a trophic overlap. But jack mackerel was not as oracious as chub mackerel, contradictorily to what was observed by others authors. Fish diet presented a high spatiotemporal variability, and the shelf break appeared as a strong biogeographical frontier. Diet composition of our fish predators was not necessarily a consistent indicator of changes in prey biomass. El Niño events had a weak effect on the stomach fullness and diet composition of chub mackerel and jack mackerel. Moreover, decadal changes in diet diversity challenged the classic paradigm of positive correlation between species richness and temperature. Finally, the global patterns that we described in this work, illustrated the opportunistic foraging behaviour, life strategies and the high degree of plasticity of these species. Such behaviour allows adaptation to changes in the environment.
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El plantejament de fer un treball final en la modalitat acadèmica permet a l’estudiant d’aprofundir en algun aspecte acadèmic que li hagi semblat interessant i del que cregui no tenir gaire o suficients coneixements. Aquest és el meu cas. En el segon any del màster vaig cursar l’assignatura Elaboracions del mite, impartida per l’Emilio Suárez, que em va permetre accedir a l’antiga Grècia amb una àmplia panoràmica que abraçava la mitologia des de diferents fonts —arqueològiques i textuals—, la història i la literatura. Si bé la majoria d’assignatures que he cursat s’han centrat —casualment— en les arts de finals del segle XIX i principis del XX, les referències a la cultura antiga han sigut constants en el màster i aquesta perseverança és el motiuque em va conduir cap a un tema que mirés cap aquest passat llunyà que, tanmateix, gaudeix de la reminiscència pròpia de qualsevol llegat.
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BACKGROUND: An understanding of the mechanisms responsible for the development and maintenance of allergic inflammation and their clinical implications is needed to develop specific and successful treatment for allergy. OBJECTIVES: To characterize in vitro T-cell responses to Der p 2, one of the major allergens of house dust mite (HDM), and investigate potential correlations between clinical and laboratory parameters. METHODS: Forty-two patients monosensitized to HDM and 10 age-matched, healthy children were studied. Dendritic cells pulsed with Der p 2 were used to stimulate autologous CD14(-) cells. Der p 2-specific T-cell activation markers, proliferation, and cytokine production profiles were examined. RESULTS: Der p 2-specific T-cell activation markers, proliferation, and T(H)2 cytokine production were significantly higher in HDM patients compared with healthy controls. Moreover, a significant correlation between proliferation and T(H)2 cytokine production was observed. Within the allergic group, skin reaction to HDM was significantly stronger in patients with a Der p 2-specific T-cell response. Levels of HDM-specific IgE directly correlated with interleukin 5 and interleukin 13 levels and with skin prick test results and, ultimately, with the patient's family history of allergy. Furthermore, the presence of atopic march correlated with T-cell proliferation. CONCLUSION: We found that, in HDM patients, Der p 2-specific T(H)2 responses, promoted by autologous dendritic cells in vitro, correlate with clinical parameters.
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Hunting live prey is risky and thought to require specialized adaptations. Therefore, observations of predatory cannibalism in otherwise non-carnivorous animals raise questions about its function, adaptive significance and evolutionary potential. Here we document predatory cannibalism on larger conspecifics in Drosophila melanogaster larvae and address its evolutionary significance. We found that under crowded laboratory conditions younger larvae regularly attack and consume 'wandering-stage' conspecifics, forming aggregations mediated by chemical cues from the attacked victim. Nutrition gained this way can be significant: an exclusively cannibalistic diet was sufficient for normal development from eggs to fertile adults. Cannibalistic diet also induced plasticity of larval mouth parts. Finally, during 118 generations of experimental evolution, replicated populations maintained under larval malnutrition evolved enhanced propensity towards cannibalism. These results suggest that, at least under laboratory conditions, predation on conspecifics in Drosophila is a functional, adaptive behaviour, which can rapidly evolve in response to nutritional conditions.
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Interactions between yellow-legged Larus cachinnans and Audouin´s Larus audouinii gulls and fisheries operating around the Chafarinas Islands, located 4.5 km off the Moroccan Mediterranean coast, are reviewed. At the Chafarinas archipelago two distinct types of fisheries operate: trawlers and purse seines. Gulls take advantage of both fisheries. They scavenge trawler discards and congregate around shoals of fish attracted to the surface by the purse-seine lamps. When both trawlers and purse-seine boats are in operation, the diet of both gull species is similar, with epipelagic fish accounting for over 60% of the biomass, partially collected in association with the purse-seine fishery. When only trawlers operated yellow-legged gulls, but not Audouin´s gulls, augmented their diet mainly with human waste from refuse dumps, suggesting that competition for food between the two species is mainly limited to the periods when resources made available by fishery activities are abundant. Likewise, when only trawlers operated, there was an increase in the predation pressure on eggs and chicks of Audouin´s gulls. In particular, during the week of celebrations for the holy lamb festival when neither fishery operated, egg losses of Audouin´s gull increased dramatically, suggesting that severe food shortage caused by the cessation of fishing can result in an increased predation pressure by yellow-legged gulls, affecting Audouin´s gull productivity. These results suggest a novel socio-ecological link between gulls, fisheries and local feasts.
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Selostus: Mehiläisen sisuspunkin aiheuttamat tuhot ja esiintyminen Suomessa
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Albert Lewin, conegut director de cinema de Hollywood influenciat pel moviment surrealista, conjumina el mite de Pandora amb la llegenda de l'Holandès errant per crear una història d¿amor exemplar, una història d¿amor foll que va més enllà del límits de la racionalitat. I, com que per creure en aquest tipus d'amor no es la raó stricto sensu la que ens ha de guiar, basteix tot un món de signes, un món semiològic complex que aquest article ajuda a desxifrar.
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Information about the population genetic structures of parasites is important for an understanding of parasite transmission pathways and ultimately the co-evolution with their hosts. If parasites cannot disperse independently of their hosts, a parasite's population structure will depend upon the host's spatial distribution. Geographical barriers affecting host dispersal can therefore lead to structured parasite populations. However, how the host's social system affects the genetic structure of parasite populations is largely unknown. We used mitochondrial DNA (mtDNA) to describe the spatio-temporal population structure of a contact-transmitted parasitic wing mite (Spinturnix bechsteini) and compared it to that of its social host, the Bechstein's bat (Myotis bechsteinii). We observed no genetic differentiation between mites living on different bats within a colony. This suggests that mites can move freely among bats of the same colony. As expected in case of restricted inter-colony dispersal, we observed a strong genetic differentiation of mites among demographically isolated bat colonies. In contrast, we found a strong genetic turnover between years when we investigated the temporal variation of mite haplotypes within colonies. This can be explained with mite dispersal occuring between colonies and bottlenecks of mite populations within colonies. The observed absence of isolation by distance could be the result from genetic drift and/or from mites dispersing even between remote bat colonies, whose members may meet at mating sites in autumn or in hibernacula in winter. Our data show that the population structure of this parasitic wing mite is influenced by its own demography and the peculiar social system of its bat host.
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Fent un repas de les principals interpretacions del mite d'El polític platonic, que, en general, no donen importancia a la multiplicitat de finalitats que el mite presenta, fem notar que quan el mite no és interpretat en relació amb el dialeg que el conté en resulten interpretacions divergents. En segon lloc, quan s'interpreta conjuntament amb la resta del dialeg, normalment el mite no acaba de ser ben situat. Com a resultat obtenim I'obertura d'una nova possibilitat interpretativa que respecti la forma compositiva del mite i la seva inserció en l'estructura del dialeg.
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Els almogàvers foren un grup de guerrers mercenaris que se singularitzava en el si dels exèrcits de la Corona d'Aragó. Esmentats per Jaume el Conqueridor i descrits per Desclot, són els protagonistes dels capítols en què Ramon Muntaner narra la seva màxima gesta: l'aventura en terres bizantines, a conseqüència de la qual els reis d'Aragó seran ducs d'Atenes i Neopàtria. Posteriorment el seu exemple serà al·legat en temps de dificultat Guerra de Successi, Guerra contra Napoleó fins que la Renaixença els reivindicarà i en farà un mite. El present article estudia com els tractà la literatura catalana, i també la castellana, des dels primers textos i sobretot durant els segles XIX i XX, en un recorregut en què es revela com un mite imperfecte, car els aspectes violents remarcats per la propaganda hel·lènica han estat un llast impossible d'eliminar.