Criação em laboratório e tabela de vida de Allograpta exotica (Diptera, Syrphidae)

Abstract

The flower flies (Diptera: Syrphidae) are considered a species-rich family, presenting high biological diversity. There are 202 valid genera, of which 60 occur in the Neotropical Region. Most adults are flower visitors and can perform important pollinators. On the other hand, larvae present different feeding habits and habitats, being predominantly predators, saprophagous, phytophagous and mycophagous, being potentially good bioindicators. The species Allograpta exotica (Wiedemann, 1830) has a wide geographic distribution, being an important natural enemy of agricultural pests in several economically important crops, especially aphids. Despite the potential of A. exotica as biological control agent for aphids, studies on the biology of this species are very limited. This work aimed to verify the possibility of maintaining colonies (and consequent generations) of A. exotica in laboratory without supplying flowers as part of the diet of the colonies; and elaborate age-stage, two-sex life table for A. exotica to estimate the birth, mortality, life expectancy, and fecundity rates of this species. The experiment was carried out in rearing chamber (25ºC ±1ºC, 70 ± 10% RH and photophase of 14 hours) and following the pre-established protocols in the laboratory of rearing Syrphidae of the Graduation Program in Entomology of the UFLA. At least six generations of A. exotica were obtained in laboratory and it was not possible to eliminate flowers as a food resource for the maintenance of colonies of this species. The life table of A. exotica was determined using the aphid Myzus persicae (Sulzer) (Hemiptera, Aphididae) as prey. The average developmental time was 2.0; 7.36 and 6 days for eggs, larvae and pupae, respectively, and 15.08 days from egg to adult emergence. The age specific survival rate was determined and the highest mortality occurred in the larval stage, followed by the pupal stage. The average fecundity of the females obtained was 221.07 eggs per female, and requiring an average of 10.1 days for maturation of the reproductive system. Therefore, with the results obtained, it is necessary to improve the rearing techniques of A. exotica in laboratory to properly understand the population dynamics for applied purposes.