Drosofilídeos associados a inflorescências de Cestrum (Solanaceae) nas áreas do Campus de Pesquisa e do Parque do Museu Paraense Emílio Goeldi

Abstract

The species of the flavopilosa group (Drosopbila) are exclusively floriferous and have Cestrum species (Solanaceae) as hosts. These plants are found on the margins of trails and forest edges. This work aims to identify the occurrence of Cestrum at the Research Campus (CP) and the Zoobotanical Park (PZB) of the Goeldi Museum, to relate the drosophilids associated with these plants, and to identify the pattern of flowering and occupation of these flowers by the species. All individuals of Cestrum present were marked, identified and observed weekly, from April/2000 to May/2001. The flowers were observed for drosophilid visitation, collected and taken to the laboratory to await emergence of adults. The emerged insects were identified, mounted and kept in the collection of the Goeldi Museum. An exception to this procedure was made in the first week of March 2001, when the flowers were dissected to verify the presence of immatures. All twenty individuals of Cestrum (19 in the CP and 1 in the PZB) were identified as C. laevigatum. Only one Drosopbila melina (flavopilosa group) was observed visiting the flowers. We obtained 714 emergent drosophilids, 537 of which were Drosopbila melina and 177 of the genus Zygothrica (2 morphospecies). Synchronous flowering occurred throughout the year, interspersed with peaks and periods of low flowering. The occupancy of the flowers by emergers was 2.3%. But it was distinct for Drosopbila melina (1.78 %), and Zygothrica (0.38 %) and varied from 1.7 to 12.5 % between flowering periods. The occupancy calculated from immatures in March 2001 (55%) was higher than that obtained from emergers in the same month (1.67%), but these data are from separate collections where the total number of flowers in the field also varied. These results indicate that the occupation of flowers by drosophilids is not proportional to the availability of the resource.