MORFOLOGIA DA ASA EM ESPÉCIES DE Drosophila (Diptera: Drosophilidae) DE OCORRÊNCIA NA MATA ATLÂNTICA BRASILEIRA: VARIABILIDADE FENOTÍPICA E HERDABILIDADE

Abstract

Estimates of heritability can be obtained by several methods. However, in insects, the crossenvironment is the best approach, and it involves the regression of the phenotypic values of the females collected in nature against the means of F1 offspring obtained in the laboratory from these females of nature. Three species of Drosophila were studied in the present work, D. maculifrons, D. mediopunctata and D. willistoni. The first two are phylogenetically related, belonging to the subgenus Drosophila and occurring in forest fragments of the Atlantic Forest. The third species belongs to another subgenus (Sophophora) and shows broader occurrence, being found in both forests and anthropized environments. Thus, the objective of this work was to quantify the morphological variation of the wing and to estimate the heritability of its morphology in D. maculifrons, D. mediopunctata and D. willistoni, collected at Fazenda Santa Cecilia in Cajuru-SP (CAJ), Parque Natural Municipal das Araucárias em Guarapuava-PR (PMA), and Morro Santana in Porto Alegre-RS (POA), aiming to use these parameters to understand aspects related to the morphological evolution of this marker in these species. Most of the variance found was due to size, with different patterns among species, which may be a result of the species characteristics and environments. Regarding shape, the changes occurred mainly in the distal portion of anterior region of the wing of all species. The values of the heritability estimates obtained varied between 3% and 90% for the size, and excepting the negative estimate for PC3 of D. maculifrons in CAJ, varied between 11% and 88% for shape, not showing a clear pattern. These results may be due to environmental factors that directly affect the amount of variation in nature and/or because of genotype and environment interaction. Finally, the relatively high estimates of shape heritability obtained in the two populations of D. maculifrons may be related to the cohesion pattern of the interpopulational morphological variation detected for this species.