Evaluation of the courtship and of the hybrid male sterility among Drosophila buzzatii cluster species (Diptera, Drosophilidae)
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Data
2002-11-01
Autores
MACHADO, L. P. de B.
CASTRO, J. P.de [UNESP]
MADI-RAVAZZI, L. [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Instituto Internacional de Ecologia
Resumo
No grupo repleta de Drosophila, o estabelecimento de subgrupos e complexos realizado com base em evidências citológicas e morfológicas é suportado por testes de isolamento reprodutivo. Entre as espécies do grupo repleta, o cluster buzzatii, devido a seu politipismo e polimorfismo, é um excelente material para estudos ecológicos e de especiação. Alguns cruzamentos interespecíficos envolvendo linhagens de Drosophila seriema, Drosophila sp. B, D. koepferae e D. buzzatii foram completamente estéreis, enquanto outros produziram híbridos F1 que não deixaram F2. No presente trabalho são apresentados dados sobre a duração da corte e ocorrência de cópula dos intercruzamentos estéreis e dados sobre a mobilidade dos espermatozóides dos híbridos F1 que não deixaram F2. Não houve ocorrência de cópula no período de 1 hora de observação e os espermatozóides dos híbridos analisados não foram móveis em qualquer das idades testadas (3, 7, 9 e 10 dias de idade). Houve alta variação na duração média da corte e na porcentagem dos machos que cortejaram as fêmeas. A ausência de cópula e esterilidade dos machos F1 indica mecanismos pré e pós-zigótico operando entre as espécies desse cluster. Os dados também mostram diferentes níveis de compatibilidade reprodutiva entre linhagens classificadas como da mesma espécie mas de diferentes localidades geográficas.
In the Drosophila repleta group the establishment of subgroups and complexes made on the basis of morphological and cytological evidences is supported by tests of reproductive isolation. Among species in the repleta group, the buzzatii cluster, due to its polymorphism and polytipism, is an excellent material for ecological and speciation studies. Some interspecific crosses involving Drosophila seriema, Drosophila sp. B, D. koepferae and D. buzzatii strains were completely sterile while others involving strains from these species produced F1 hybrids that did not yield F2. In the present work, data on courtship duration and copula occurrence obtained in the analysis of flies from parental sterile crosses and on spermatozoon mobility observed in F1 hybrids that did not yield F2 are presented. Copula did not occur during one hour of observation and the spermatozoon also did not show mobility at any of the analyzed stages (3, 7, 9 and 10 days old). There was a high variation in courtship average duration and in the percentage of males that courted the females. The reproductive isolation mechanisms indicated by these observations were pre and post-zygotic, as supported by the absence of copula and male sterility. Data obtained also showed the occurrence of different degrees of reproductive compatibility among the strains classified as the same species but from distinct geographic localities.
In the Drosophila repleta group the establishment of subgroups and complexes made on the basis of morphological and cytological evidences is supported by tests of reproductive isolation. Among species in the repleta group, the buzzatii cluster, due to its polymorphism and polytipism, is an excellent material for ecological and speciation studies. Some interspecific crosses involving Drosophila seriema, Drosophila sp. B, D. koepferae and D. buzzatii strains were completely sterile while others involving strains from these species produced F1 hybrids that did not yield F2. In the present work, data on courtship duration and copula occurrence obtained in the analysis of flies from parental sterile crosses and on spermatozoon mobility observed in F1 hybrids that did not yield F2 are presented. Copula did not occur during one hour of observation and the spermatozoon also did not show mobility at any of the analyzed stages (3, 7, 9 and 10 days old). There was a high variation in courtship average duration and in the percentage of males that courted the females. The reproductive isolation mechanisms indicated by these observations were pre and post-zygotic, as supported by the absence of copula and male sterility. Data obtained also showed the occurrence of different degrees of reproductive compatibility among the strains classified as the same species but from distinct geographic localities.
Descrição
Palavras-chave
corte, híbridos, esterilidade do macho em Drosophila, Courtship, hybrids, male sterility in Drosophila
Como citar
Brazilian Journal of Biology. Instituto Internacional de Ecologia, v. 62, n. 4a, p. 601-608, 2002.