Parâmetros demográficos do pulgão-preto em linhagens avançadas de feijão-caupi de porte semiereto

The objective of this work was to evaluate the resistance of advanced semi-erect cowpea (Vigna unguiculata) lines, by means of a screening assay for resistance and the elaboration of fertility-life tables of Aphis craccivora (Hemiptera: Aphididae). The experiments were carried out in a screenhouse. For the resistance trial, 15 advanced cowpea lines were used, as well as two standard genotypes for resistance and two for susceptibility, which were arranged in six blocks. After resistance was determined, two lines with the highest and lowest resistance were selected for the development of the fertility-life tables which were used to estimate demographic parameters. The MNCO4-762F-03 and MNCO4-762F-09 cowpea lines were classified as resistant, for which cowpea aphids showed the lowest values (in parentheses, respectively) for: net reproductive rate (RO = 3.0 and 2.5), intrinsic rate of increase (rm = 0.16 and 0.15), and finite rate of increase (λ = 1.18 and 1.16). The highest values were obtained for the 'Vita-7', MNCO4-795F-168, and 'BRS Tumucumaque' genotypes. The MNCO4-762F-03 and MNCO4-762F-09 lines show antibiosis-type resistance, which directly affects the reproductive potential of the cowpea aphid population.O objetivo deste trabalho foi avaliar a resistência de linhagens avançadas de feijão-caupi (Vigna unguiculata) de porte semiereto, por meio de ensaio de resistência e elaboração de tabelas de vida de fertilidade de Aphis craccivora (Hemiptera: Aphididae). Os experimentos foram realizados em telado. Para o ensaio de resistência, utilizaram-se 15 linhagens avançadas de feijão-caupi, assim como dois genótipos-padrão de resistência e dois de susceptibilidade, os quais foram distribuídos em seis blocos. Após ter-se determinado a resistência, selecionaram-se as duas linhagens com o maior e o menor grau de resistência, para compor o ensaio destinado à elaboração de tabelas de vida de fertilidade que foram utilizadas para estimar os parâmetros demográficos. As linhagens de feijão-caupi MNCO4-762F-03 e MNCO4-762F-09 foram classificadas como resistentes, nas quais, o pulgão-preto apresentou os menores valores (nos parênteses, respectivamente) de: taxa líquida de reprodução (RO = 3,0 e 2,5); taxa intrínseca de crescimento (rm = 0,16 e 0,15); e razão finita de crescimento (λ = 1,18 e 1,16). Os maiores valores foram obtidos nos genótipos 'Vita-7', MNCO4-795F-168 e 'BRS Tumucumaque'. As linhagens MNCO4-762F-03 e MNCO4-762F-09 apresentam resistência do tipo antibiose, o que afeta diretamente o potencial reprodutivo da população de pulgão-preto

Preferência e parâmetros demográficos do pulgão-preto em linhagens avançadas de feijão-caupi de porte semiprostrado

The objective of this work was to determine the preference and the demographic parameters of cowpea aphid (Aphis craccivora) in advanced lines of semiprostrate cowpea (Vigna unguiculata), and to verify both the existance and type of plant resistance to this insect attack. Aphid preference to 20 cowpea genotypes was tested in a randomized complete block design, with six replicates. Lines showing the highest levels of resistance and susceptibility in the preference tests were selected for use in the demographic parameter tests. Based on aphid birth rate and mortality, fertility life tables were constructed. The MNCO4-792F-123 line was classified as resistant. The lowest values for cowpea aphid intrinsic and finite growth rates were obtained for the MNCO4-792F-123, and the highest ones for MNCO4-782F-108 and 'BRS Novaera' genotypes, whose levels exceeded those of 'Vita 7', the standard genotype for susceptibility. The MNCO4-792F-123 line is the least favorable for the development of cowpea aphid, while MNCO4-782F-108 and 'BRS Novaera' are the most susceptible ones.O objetivo deste trabalho foi determinar a preferência e os parâmetros demográficos do pulgão-preto (Aphis craccivora), em linhagens avançadas de feijão-caupi (Vigna unguiculata) de porte semiprostrado, e verificar a existência e o tipo de resistência da planta ao ataque do inseto. Avaliou-se a preferência do inseto a 20 genótipos de feijão-caupi, em delineamento de blocos ao acaso, com seis repetições. As linhagens com maior resistência e suscetibilidade nos testes de preferência foram selecionadas para compor o ensaio de parâmetros demográficos. Com base na taxa de natalidade e mortalidade do pulgão, construíram-se as tabelas de vida de fertilidade. A linhagem MNCO4-792F-123 foi classificada como resistente. Os menores valores da taxa intrínseca de crescimento e da taxa finita de crescimento do pulgão-preto ocorreram sobre a linhagem MNCO4-792F-123, e os maiores, sobre os genótipos MNCO4-782F-108 e 'BRS Novaera', que superaram o genótipo-padrão de suscetibilidade 'Vita 7'. A linhagem MNCO4-792F-123 é a menos favorável para o desenvolvimento do pulgão-preto, enquanto MNCO4-782F-108 e 'BRS Novaera' são as mais suscetíveis

Epistemological conceptions of biology majors and their transformation by an explicit proposal for teaching history and philosophy of science

This paper reports the results obtained in the test of a proposal for the teaching of history and philosophy of science to Higher Education students enrolled in courses on natural sciences. The proposal takes actual historical examples as a basis for eliciting discussions about philosophical issues. It amounts to an explicit approach, directly addressing epistemological contents, which was elaborated and tested from the perspective of a teacher-researcher. The proposal was tested through a quali-quantitative approach. Data were gathered in a class of a course on history and philosophy of science for Biology majors, through the questionnaire VNOS-C (Views of the Nature of Science, Form C), at the beginning and end of a term. They were qualitatively treated by analyzing categories built from the answers given by the students. Based on some issues agreed upon by several post-positivist theories of science, we evaluated the adequacy of the students’ epistemological views, obtaining scores for each question, the sum of which resulted in a total score for each questionnaire. The effects of the proposal on the students’ views were analyzed qualitative and quantitatively by means of a discussion of the frequencies of adequate, partially adequate, and inadequate answers to each question and a statistical test comparing the total scores of each student, in the pre- and post-tests. To analyze the effects on each epistemological aspect addressed in the questionnaire, we performed tests comparing the scores obtained by the students in each question, at the beginning and end of the term. Generally speaking, the proposal resulted in an evolution of the views about the nature of science of all students who did both the pre- and post-tests. It was more effective in promoting a change in views about the demarcation between science and other ways of knowing, the differences between laws and theories, and the relationship between models and evidence. Nevertheless, it had a more limited success in the case of views about what is an experiment, the requirement of experimental methods in scientific practice, the causes of theoretical change, and the possibility of drawing different conclusions from the same data