908 resultados para Mating preference


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The Nile tilapia fish (Oreochromis niloticus) has a high potential to be used as a model in neuroscience studies. In the present study, the preference of the Nile tilapia between a gravel-enriched (GEE), a shelter-enriched (SEE) or a non-enriched (NEE) environment was determined, for developing a place preference model. Nile tilapia had an initial preference for GEE, but after 1 day of observation, the fish stabilized their frequency of visits among compartments. Hence, any stimulus motivating tilapia increase in compartment visiting indicates a positively reinforcing effect. This feature is very useful for the development of new behavioural paradigms for fish in tests using environmental discrimination, such as the conditioning place preference test. © 2006 Elsevier GmbH. All rights reserved.

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This paper reports the effect of mating delay on the queen Apis mellifera ovaries based on a light microscopy analysis. Soon after a queen emerges from the brood cell, oocytes start to differentiate in the ovaries, but if mating does not occur at the correct age (about 6 days after emergence) cell degeneration begins. Ovaries of 15-day-old virgin queens show extensive disorganization with cell death affecting all types of ovariole cells. Types of cell death and the possible causes are discussed.

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Aim: This study evaluated the prevalence of the chewing side preference (CSP) in the deciduous, mixed and permanent dentitions. Materials and methods: Three-hundred subjects were divided in three groups (n = 100): Group 1 - children with deciduous dentition; group 2-children with mixed dentition; group 3 - subjects with permanent dentition. The CSP was determined using a direct method (visual observation) developed by McDonnell et al. (2004). Descriptive statistic was used to observe the prevalence of CSP. The Pearson's Chi-square was used to investigate signicant associations between gender, presence of CSP and preferred side (right/left). Results and conclusion: Eighty-seven percent of group 1 had a CSP. Eighty-two percent of group 2 had a CSP. Seventy-six percent of group 3 had a CSP. There was no statistically significant association between presence of CSP and gender in all groups. There was no statistically significant association between preferred side (right/left) and gender in all groups. Clinical significance: There is a higher prevalence of subjects in deciduous, mixed and permanent dentition that presented chewing side preference. The early diagnosis of the presence of chewing side preference can prevent the unilateral chewing pattern with prophylactic therapy applied to the first teeth (deciduous).

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Orange cakes with addition of inulin and oligofructose to justify a prebiotic claim (minimum of 3 g of fructans in a 60 g serving of cake) were investigated regarding sensory aspects. The sensory profile of cakes with inulin, with inulin/oligofructose and without prebiotics (standard cake) was evaluated using descriptive quantitative analysis. Preference mapping was assessed using multidimensional scaling on data obtained through an acceptability test with a nine-point hedonic scale. The cakes with prebiotics presented greater crust brownness, dough beigeness, hardness and stickiness than the standard cake and lower crumbliness. Principal Component Analysis (69.5 and 10.7% of explanation to the first and second principal components, respectively) showed that crust brownness, dough beigeness, hardness and stickiness contributed to distinguish the cakes with prebiotics from standard cakes. The sensory acceptability was similar for the three cakes and higher when compared to three commercial cakes, but the preference mapping showed that cakes with prebiotics were preferred to commercial cakes. Addition of prebiotics in orange cakes is feasible, based on the sensory results, which may facilitate marketing of this functional food with sensorial qualities equivalent to conventional products. © 2012 Elsevier Ltd.

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Includes bibliography

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The red gum lerp psyllid Glycaspis brimblecombei Moore (Hemiptera: Psyllidae) was first recorded in Brazil in 2003 and since then has caused serious damage in Eucalyptus forests. The damage is mainly due to defoliation, sooty mold and dieback, thus requiring the development of efficient management strategies. The settling and ovipositional preference of G. brimblecombei by species and clones of Eucalyptus were evaluated in free- and no-choice tests. Preliminary tests were done to determine the density of psyllid couples that produced the greatest densities of eggs, leaf position selection for oviposition, and whether oviposition was affected by preimaginal conditioning. Apical leaves were used more frequently for oviposition by the psyllid, and the number of eggs decreased from the apex to the base. The densities of 10 and 15 psyllid couples per seedling produced the highest oviposition. There was no evidence of preimaginal conditioning. In the free-choice test, E. grandis, E. urophylla, VM-1, I-144, C-219 and H-13 were less attractive to G. brimblecombei adults, with H-13, E. grandis and E. urophylla having the least oviposition. In the no-choice test, E. urophylla, GG-100 and E. grandis also demonstrated a lower oviposition, but E. camaldulensis and 3025 were highly susceptible. The low preference for the genotypes E. grandis and E. urophylla suggests the occurrence of a non-preference type resistance against the red gum lerp psyllid. Our results can be utilized for the development of management programs for G. brimblecombei in Eucalyptus forests. © 2012 Springer Science + Business Media B.V.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Self-compatibility in apomictic pseudogamic species is considered fundamental to assure reproduction by seeds in extreme situations, making apomictic species more advantageous than sexual ones in these scenarios. Anemopaegma acutifolium is a polyploidy, apomictic sporophytic species with no endosperm development in ovules of unpollinated pistils, which indicates obligate pseudogamy. Thus, the aim of the present work is to study the breeding system and post-pollination events to test if there is similar pseudogamous development irrespective of pollination treatment. We analysed fruit and seed set obtained in controlled experimental pollinations, as well as embryo number per seed, and the progress of ovule penetration, fertilisation and early endosperm development between self- and cross-pollinated pistils. We found that the species is self-fertile and that spontaneous selfing fruit set is also possible, although emasculated flowers never form fruits. Selfed pistils were as efficient as crossed ones for all parameters analysed, except for a delay in endosperm development observed in the former that may be an effect of the late-acting self-incompatibility. Therefore, the avoidance of selfed pistil abortion seems to be promoted by the presence of adventitious embryos and a normal endosperm. We conclude that A. acutifolium shows apomixis-related pseudo-self-compatibility, as in other self-fertile apomictic species of Bignoniaceae, which confer reproductive assurance and increases fruit-set and persistence ability in fast-changing tropical habitats. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

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Phylogenetic approaches based on mitochondrial DNA variation (fragments of Cyt B and 16S ribosomal RNA) have revealed Triatoma sherlocki as the most recent species addition to the Triatoma brasiliensis species complex; a monophyletic group which includes T. brasiliensis, Triatoma melanica, and Triatoma juazeirensis. T. sherlocki is the most differentiated among all species of this complex: it is unable to fly, possesses longer legs than the other members, and has reddish tonality in some parts of its exochorion. We question whether these species are reproductively compatible because of this pronounced morphological differentiation, and therefore, we present a series of cross breeding experiments that test compatibility between T. sherlocki and other members of the T. brasiliensis complex. We extended our analyses to include crosses between T. sherlocki and Triatoma lenti, because the latter has been suggested as a possible member of this complex. T. sherlocki male. ×. T. lenti female pairs failed to produce hybrids. All other crosses of T. sherlocki and members of T. brasiliensis species complex, as well as backcrosses, produced viable offspring through the third generation. This study stresses the importance of searching for the features that may isolate members of the T. brasiliensis species complex. © 2013 Elsevier B.V.

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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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The objective was to evaluate the effect of nutritional density and season on the performance of young rabbit does before the first mating. Forty-eight females from the Botucatu Genetic Group were used in each season (warm or cool), starting at the age of 70 days, housed in groups of four per cage up to 119 days, and reared individually from 120 to 140 days of age. The high-density diet was formulated to contain, on a 90% DM basis, 18.4% CP, 16.5% ADF and 2,500 kcal DE kg-1; whereas the low-density diet was formulated to contain 14.7% CP, 24% ADF and 2,000 kcal DE kg-1. The experiment was conducted according to a 2x2 factorial design (two diets x two seasons) with repeated measures (weeks). The high-density diet promoted lower feed intake, higher final weight, and higher daily weight gain, adjusted for constant intake. But these facts alone do not warrant using a high-density diet for growing rabbit does, because it could have a negative impact during the reproductive phase. In the warm season, there was a reduction in feed intake and an improvement in feed efficiency. Along time, however, the mean body weight of does was similar in the two seasons.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)