997 resultados para predation


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Ciências Biológicas (Zoologia) - IBRC

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This work describes the foraging techniques, body positions and behavior of free-ranging Ingram's squirrel Guerlinguetus ingrami Thomas, 1901 in a region of the Araucaria moist forest, in the Atlantic Forest of southern Brazil. The animals were observed using the all occurrence sampling method with the aid of binoculars and a digital camcorder. All behaviors were described in diagrams and an ethogram. We recorded five basic body positions, 24 behaviors, two food choices, and three feeding strategies utilized to open fruits of Syagrus romanzoffiana (Cham.), the main food source of Ingram's squirrels. We also observed a variance in the animals' stance, which is possibly influenced by predation risk, and discuss the causes of some behaviors.

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Distinct genetic structure in populations of Chrysoperla externa (Hagen) (Neuroptera, Chrysopidae) shown by genetic markers ISSR and COI gene. Green lacewings are generalist predators, and the species Chrysoperla externa presents a great potential for use in biological control of agricultural pests due to its high predation and reproduction capacities, as well as its easy mass rearing in the laboratory. The adaptive success of a species is related to genetic variability, so that population genetic studies are extremely important in order to maximize success of the biological control. Thus, the present study used nuclear (Inter Simple Sequence Repeat - ISSR) and mitochondrial (Cytochrome Oxidase I - COI) molecular markers to estimate the genetic variability of 12 populations in the São Paulo State, Brazil, as well as the genetic relationships between populations. High levels of genetic diversity were observed for both markers, and the highest values of genetic diversity appear associated with municipalities that have the greatest areas of native vegetation. There was high haplotype sharing, and there was no correlation between the markers and the geographic distribution of the populations. The AMOVA indicated absence of genetic structure for the COI gene, suggesting that the sampled areas formed a single population unit. However, the great genetic differentiation among populations showed by ISSR demonstrates that these have been under differentiation after their expansion or may also reflect distinct dispersal behavior between males and females.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The preference of predation on oocytes of Piaractus mesopotamicus, commonly known as 'Pacucaranha', by the prawn Macrobrachium amazonicum, under laboratory conditions, was evaluated regarding to other food items. The prawns were collected with sieves, placed below the underwater vegetation, and maintained in aquarium (12 L each) at a density of 10 individuals/aquarium for acclimatization. Oocytes (O) of P. mesopotamicus were obtained from the disposal of artisanal fishery. Artificial feed (R), fish muscle (M), organic matter accumulated in roots of Salvinia sp. (S) and plant organic matter in decomposition (MV) items were used to compare the preference by M. amazonicum. In all experiments the average of the prawns preying oocytes were higher; significant differences were detected only when comparing O/P and O/M. The preference for oocytes may be due to the presence of yolk, which has a high nutritional value and easy assimilation, in contrast to others items, which resent certain rigidity. This prawn species is exotic on site and the results of this study shows a possible environmental impact on P. mesopotamicus in the region.

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This experiment evaluated temperament, vaginal temperature, and plasma cortisol in beef cows from wolf-naive and wolf-experienced origins that were subjected to a simulated wolf encounter. Multiparous, pregnant, nonlactating Angus-crossbreed cows from the Eastern Oregon Agricultural Research Center located near Burns, OR (CON; n = 50), and from a commercial operation near Council, ID (WLF; n = 50), were used. To date, grey wolves are not present around Burns, OR, and thus CON were naive to wolves. Conversely, wolves are present around Council, ID, and WLF cows were selected from a herd that had experienced multiple confirmed wolf-predation episodes from 2008 to 2012. Following a 50-d commingling and adaptation period, CON and WLF cows were ranked by temperament, BW, and BCS and allocated to 5 groups (d 0; 10 CON and 10 WLF cows/group). Groups were individually subjected to the experimental procedures on d 2 (n = 3) and d 3 (n = 2). Before the simulated wolf encounter, cow temperament was assessed and blood samples and vaginal temperatures (using intravaginal data loggers) were collected (presimulation assessments). Cows were then sorted by origin, moved to 2 adjacent drylot pens (10 WLF and 10 CON cows/pen), and subjected to a simulated wolf encounter event for 20 min, which consisted of 1) cotton plugs saturated with wolf urine attached to the drylot fence, 2) continuous reproduction of wolf howls, and 3) 3 leashed dogs that were walked along the fence perimeter. Thereafter, WLF and CON cows were commingled and returned to the handling facility for postsimulation assessments, which were conducted immediately after exposure to wolf-urine-saturated cotton plugs, wolf howl reproduction, and 20-s exposure to the 3 dogs while being restrained in a squeeze chute. Chute score, temperament score, and plasma cortisol concentration increased (P <= 0.01) from pre- to postsimulation assessment in WLF but did not change in CON cows (P >= 0.19). Exit velocity decreased (P = 0.01) from pre-to postsimulation assessment in CON but did not change (P = 0.79) in WLF cows. In addition, WLF cows had a greater (P = 0.03) increase in temperature from pre-to postsimulation assessments compared with CON cows. In conclusion, the simulated wolf encounter increased excitability and fear-related physiological stress responses in cows that originated from a wolf-experienced herd but not in cows that originated from a wolf-naive herd.

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The gall-forming thrips Gynaikothrips ficorum Marchal (Thysanoptera: Phlaeothripidae) is recorded in all regions where its host plant, Ficus microcarpa (Marchal) (Moraceae), has been cultivated as an urban and interior landscape plant species, including potted plants and bonsai. Similarly, the thrips predator Montandoniola confusa Streito & Matocq (Hemiptera: Anthocoridae) has generally followed the prey distribution. The gall induced by thrips degrades the plant foliage, and the thrips themselves can be annoying for people both outdoors and indoors. The galls, however, create a microcosm with all developmental stages of the thrips and its predator. In this study we present the first records of M. confusa in South America, document the species' widespread concomitant occurrence across Brazil, and report our studies of three aspects of M. confusa predation upon the eggs, larvae/prepupae, and adults of G. ficorum thrips: (i) functional response of the predator adult female as a function of different densities of thrips eggs, larvae/prepupae and adults separately: (ii) predation on eggs by adult M. confusa with adult thrips present in the gall; and (iii) adult M. confusa prey preferences when all thrips stages occurred simultaneously in the gall. For all three thrips life stages tested, the predator exhibited a type II functional response. Despite the availability of different life stages in the gall, M. confusa adults are capable of preying upon all life stages of G. ficorum, predation was preferentially on thrips eggs, with an estimated similar to 10-fold greater predation on eggs compared to larvae/prepupae and adult thrips. Egg predation was unaffected by the presence of defensive adult thrips in the gall under low densities (<30 eggs/gall) but when egg densities were greater than 30 eggs/gall, it was reduced when adult thrips were present. However, the relative number of thrips adults per gall did not statistically change the outcome. (C) 2013 Elsevier Inc. All rights reserved.

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The effect of Bacillus thuringiensis Berliner 1911 var aizawai strain GC-91 (Bta) on the biological parameters and phytophagy of Podisus nigrispinus (Dallas 1851) (Hemiptera: Pentatomidae) were evaluated using the follow treatments: a) provision of deionized water and prey Plutella xylostella (Linnaeus 1758) (Lepidoptera: Plutellidae); b) provision of only a solution containing Bta; and c) provision of prey and the solution containing Bta. To evaluate the phytophagy of the predator, leaves of Brassica oleraceae var acephala Linnaeus cv Manteiga da Georgia were provided and replaced every two days, and subsequently stained by immersion in 1% acid fuchsin. Staining enabled the visualization of the feeding sheath, which allowed for the quantification of punctures inflicted by P nigrispinus. The phytophagy, reproductive capacity and biological cycle in P nigrispinus were negatively affected by the presence of Bta; however, its predatory capacity was not altered.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The belief in the existence of an ecological crisis that would affect the future of the planet, is one of the factors that causes the appearance of ecological concern, resulting in the adoption of non-predatory consumer practices and more respectful relationships with non-humans beings. This study starts from the assumption of the existence of an environmental question, and aims to investigate some of the cultural causes of human predation and identify possible ways in which environmental question can be treated critically to search overcomes. Follows the reasoning that western society as a complex of social relations, the capitalism, as a mode of production utilities and rational right, are all consequences of the modern rationality, cognitive and moral logic that transforms people and nature in satisfaction instruments of individual interests. However, despite being identified as the causative root of environmental question, modern rationality takes with it enough to promote the development of ecological respect, necessary in confronting and overcoming the environmental question, as it will be applied as a principle in redefinition of the relationship of human beings with themselves and with nature. And modern rationality can also make capitalism more efficient in the use and reuse of materials so as to consume fewer resources on the planet to satisfy human needs.