Avaliação do potencial de Syrphidae e Asilidae como agentes de controle biológico das cigarrinhas das pastagens

Abstract

The main predatory species of families Syrphidae and Asilidae were registered and the environmental changes caused by the conversion of a monoculture system of B. decumbens into a silvipastoral one were analyzed to verify whether they would alter the predators´ diversity, abundance and constancy. Further, the biological and behavioral aspects involved in the breeding of S. nigra were investigated to obtain in-depth information for effective and viable predator production for future use in spittlebug integrated management programs. Initially, insects were collected by malaise traps installed in a B. decumbens monoculture system and in a silvipastoral system. Syphidae and Asilidae abundance was determined by calculating the number of morphospecies, whilst diversity and constancy indexes were calculated by Shannon-Wiener and Bodenheimer methodologies, respectively. The second section comprised the assessment of females´ fertility, egg viability, duration and viability of the larva and pupa stages. Behavioral aspects were observed by olfactory response of mated females with a Y-type olfactometer. It was revealed Syphidiae and Asilidae species with capacity to biological control agents of pasture pests. Results revealed that environmental changes caused by the conversion of B. decumbens monoculture system into silvipastoral system altered the ecological indexes evaluated for the family Syrphidae, which may be used as a bioindicator. Although adults, eggs and pupae of S. nigra may be kept in the laboratory, however larval viability was low, in this way new studies are necessary to reduce this low viability