888 resultados para Information Behaviour
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Optimal foraging theory assumes that predators use different prey types to maximize their rate of energetic gain. Studies focusing on prey preference are important sources of information to understand the foraging dynamics of Chrysomya albiceps. The purpose of this investigation is to determine the influence of larval starvation in C. albiceps on the predation rate of different prey blowfly species and instars under laboratory conditions. Our results suggest that C. albiceps prefers Cochliomyia macellaria larvae to Chrysomya megacephala under non-starvation and starvation conditions. Nevertheless, predators gained more weight consuming C. macellaria. This result suggests that C. albiceps profit more in consuming C. macellaria rather than C. megacephala. The foraging behaviour displayed by C. abiceps on their prey and the consequences for the blowfly community are also discussed.
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In this study we describe pacus, Piaractus mesopotamicus, detecting the presence of a predator by conspecific alerting pheromone. Moreover, we investigate whether this chemical information indicates the presence of a specific predator, or whether it indicates general disturbance. We exposed groups of pacus to the view of a predator fish (trahira, Hoplias malabaricus), a non-predator fish (piracanjuba, Brycon orbignyanus) or an aquarium without any fish (control), and then we transferred their water to isolated conspecifics. We set up six trials of each condition in which we analysed the dispersion and the distance from the visual stimulus in water-donor fish and the distance from the chemical stimulus in water-receiver pacus. This study showed that pacus visually identified the presence of another fish and recognised it as predator or non-predator. This is interpreted as an innate response. Such heterospecific detection affects the behaviour of pacus, which release chemicals that induce conspecifics to adopt a similar behavioural response. At least two chemicals might be involved, one of them possibly an alerting pheromone.
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This study provides information concerning the feeding behaviour of Goniopsis cruentata (Latreille, 1803), through analysis of stomach contents according to demographic categories. Collections were carried out monthly from May 2005 through April 2006 in a subtropical estuary on the southeastern Brazilian coast (23 degrees 29'24 '' S 45 degrees 10'12 '' W). The crabs were collected by hand, with a 2-hour sampling effort by three people. In the laboratory, the crabs were sexed and measured for greatest carapace width, and grouped into demographic categories: adult males, juvenile males, adult females, juvenile females, and ovigerous females. For the fullness analysis, the stomachs were grouped into two categories: (1) E = Empty, with no food; and (2) F = Full, whether partially filled or totally. The frequency-of-occurrence method was used to characterize feeding behaviour, and the demographic categories recognired were compared. We obtained stomachs from 171 adult males, 69 juvenile males, 136 adult females, 72 juvenile females, and 41 ovigerous females, of which 85.6% were full. of the eight food items recorded, sediment was the most frequent, and unidentified material was the least. Goniopsis cruentata can be characterized as a generalist feeder, exploiting most of the food items available in the mangrove swamps. In spite of this generalist behaviour, the dominant presence of sediment suggests that G. cruentata is primarily a detritivore that exploits particulate organic matter from microbial biodegradation, one of the most important mangrove functions. The trophic role of this crab in the ecosystem showed no significant differences among the demographic categories, and seems to be wider than those observed for sesarmid and ocypodid mangrove crabs. These ecosystem engineers may occupy different positions in the trophic chains of estuarine environments.
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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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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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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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Solid state Ln-4-Me-BP compounds, where Ln stands for lighter trivalent lanthanides (lanthanum to europium) and 4-Me-BP is 4-methylbenzylidenepyruvate, have been synthesized. Elemental analysis, complexometry, X-ray powder diffractometry, infrared spectroscopy and simultaneous thermogravimetry-differential thermal analysis (TG-DTA), have been used to characterize and to study the thermal behaviour of these compounds. The results provided information concerning the stoichiometry, crystallinity, thermal stability and thermal decomposition. (C) 2002 Elsevier B.V. B.V. All rights reserved.
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Solid-state M-2-Cl-BP, where M stands for Mn, Fe, Co, Ni, Cu, Zn and Pb and 2-Cl-BP is 2-chlorobenzylidenepyruvate, have been synthesized. Thermogravimetry and derivative thermogravimetry (TG/DTG), simultaneous thermogravimetry and differential thermal analysis (TG-DTA), X-ray powder diffractometry, infrared spectroscopy, elemental analysis, and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, thermal stability and thermal decomposition of the isolated compounds.
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Solid-state Ln(Bz)(3)center dot H(2)O compounds where Ln stands for trivalent yttrium or lanthanides and Bz is benzoate have been synthesized. Simultaneous thermogravimetry-differential thermal analysis (TG-DTA), X-ray powder diffractometry, infrared spectroscopy and chemical analysis were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, thermal stability and thermal decomposition of the isolated compounds.
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Solid-state Ln-4-MeO-Bz compounds, where Ln stands for trivalent Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y and 4-MeO-Bz is 4-methoxybenzoate, have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results led to information about the composition, dehydration, phase transition, coordination mode, structure, thermal behaviour and thermal decomposition of the isolated compounds. The phase transition observed in the some compounds has been reported for the first time. (C) 2006 Elsevier B.V. All rights reserved.