Uso de recursos tróficos por Drosophila nasuta (Lamb, 1914) na Floresta Atlântica de Pernambuco

Abstract

The family Drosophilidae, represented by vinegar flies, is characterized by insects that play a fundamental role in the saprophytic chain, especially in fruits. In recent decades the number of invasive species of this family has been increasing in Brazil, with Drosophila nasuta being one of the most recent cases of successful invasion. Although there is research on its abundance and distribution in the various Brazilian biomes, aspects of its trophic ecology and competitive ability in larval development are not yet known. The present study evaluated the use of trophic resources by D. nasuta for larval development in the Atlantic Forest, domain of Pernambuco. Native fruits of cajá, oiti, acerola, pitanga, pitomba, and exotic fruits of mango, almond, blackberry, jackfruit, jambo, dendê, sapoti, guava, and trapiá were investigated. The fruits were collected on the ground, distributed in jars and sealed until the adult drosophilids hatched. The drosophilids were identified and their abundance was recorded, as well as the hatching rate of larvae per fruit. Shannon-Wiener indices were calculated to attest to trophic amplitude, Pianka's index for niche overlap and Pielou's equitability to attest to the preference of D. nasuta for the sampled fruits. A total of 2,874 drosophilids were identified, with 97.32% belonging to exotic species. Drosophila nasuta was the seventh most abundant species, hatching in four native and one exotic fruit, and also being most present in jambo. The niche amplitude of D. nasuta was H' = 1.20. D. nasuta showed high niche overlap with the exotic species D. ananassae, D. kikkawai and D. malerkotliana. Drosophila nasuta showed the greatest uniformity in resource use among the exotics. It showed a generalist character, hatching mainly from native fruits and in a shorter time than the native drosophilid species. With these data, it can be seen that the preference of D. nasuta for native fruits may indicate a danger to Neotropical drosophilid communities in the Atlantic Forest. That said, the information obtained in this study is fundamental to understand part of the dynamics of the invasion and success of this species in the Atlantic Forest.