32 research outputs found

    Investigating the relationship between pollination strategies and the size-advantage model in zoophilous plants using the reproductive biology of Arum cylindraceum and other European Arum species as case studies

    Get PDF
    The size-advantage model (SAM) explains the temporal variation of energetic investment on reproductive structures (i.e. male and female gametes and reproductive organs) in long-lived hermaphroditic plants and animals. It proposes that an increase in the resources available to an organism induces a higher relative investment on the most energetically costly sexual structures. In plants, pollination interactions are known to play an important role in the evolution of floral features. Because the SAM directly concerns flower characters, pollinators are expected to have a strong influence on the application of the model. This hypothesis, however, has never been tested. Here, we investigate whether the identity and diversity of pollinators can be used as a proxy to predict the application of the SAM in exclusive zoophilous plants. We present a new approach to unravel the dynamics of the model and test it on several widespread Arum (Araceae) species. By identifying the species composition, abundance and spatial variation of arthropods trapped in inflorescences, we show that some species (i.e. A. cylindraceum and A. italicum) display a generalist reproductive strategy, relying on the exploitation of a low number of dipterans, in contrast to the pattern seen in the specialist A. maculatum (pollinated specifically by two fly species only). Based on the model presented here, the application of the SAM is predicted for the first two and not expected in the latter species, those predictions being further confirmed by allometric measures. We here demonstrate that while an increase in the female zone occurs in larger inflorescences of generalist species, this does not happen in species demonstrating specific pollinators. This is the first time that this theory is both proposed and empirically tested in zoophilous plants. Its overall biological importance is discussed through its application in other non-Arum systems

    Comportamento anoréxico e percepção corporal em universitários Anorexic behavior and body self-perception on universitarians

    No full text
    OBJETIVO: Avaliar a percepção corporal e a prevalência de sintomas de anorexia nervosa em estudantes universitários. MÉTODOS: Estudo transversal, no qual a seleção da amostra foi realizada por conveniência. Aplicou-se o questionário teste de atitudes alimentares (EAT- 26) e teste de imagem corporal, para avaliar os sintomas de anorexia nervosa e a percepção corporal, respectivamente. Para a análise estatística dos dados utilizou-se o teste binomial para verificar a existência de associação entre as variáveis qualitativas. RESULTADOS: Participaram do estudo 149 estudantes de nutrição e 78 estudantes de educação física. Observou-se que 10,3% e 14,1% dos estudantes de educação física e nutrição, respectivamente, apresentaram fatores de risco para desenvolver anorexia nervosa e o teste de imagem corporal evidenciou proporções elevadas de insatisfação com a forma corporal, em ambos os cursos: 75,8% e 78,2% para os cursos de nutrição e educação física, respectivamente. CONCLUSÃO: Os estudantes de nutrição mostraram maior tendência de apresentar comportamento de risco para anorexia nervosa, com predominância no sexo feminino. Além disso, os resultados evidenciaram proporções elevadas de insatisfação com a imagem corporal, em ambos os cursos. Estes resultados são preocupantes, tendo em vista que são futuros profissionais que possuem papel fundamental na detecção e, no caso do nutricionista, no manejo destes distúrbios.<br>OBJECTIVE: To assess body perception and prevalence of symptoms of nervous anorexy in college students. METHODS: Cross-sectional study with convenience sample. We used the Eating Attitudes Test questionnaire (EAT-26) and the Body Image Test to evaluate symptoms of nervous anorexy and the body perception on the participants, respectively. In the statistical analysis, Binomial test was used to assess the association between qualitative variables. RESULTS: This study included 149 nutrition and 78 physical education students. The results showed that 10.3% and 14.1% of the physical education and nutrition students, respectively, presented risk factors for the development of anorexy, and the Body Image Test revealed high levels of dissatisfaction regarding body shape of students in both courses: 75.8% and 78.2% in nutrition and physical education, respectively. CONCLUSION: Students of nutrition showed greater tendency to present risk behavior for developing nervous anorexy, predominantly in females. Moreover, the results showed high proportions of dissatisfaction with body image in both courses. These results raise concern, since the physical education teachers and nutritionists are the professionals who play a key role in detecting and, in the case of a nutritionist, managing these disorders
    corecore