Establishment for laboratory rearing of salpingogaster nigra (diptera: syrphidae) and the disclosure of a new species

Abstract

Syrphid flies constitute a group of high diversity and ecological importance, acting both as pollinators and as natural enemies of insect pests. Within the genus Salpingogaster, Salpingogaster nigra stands out, recognized as an efficient predator of spittlebugs, one of the main livestock pests in Brazil. Therefore, the use of this species in biological control presents great potential within integrated pest management, especially due to its ability to locate and consume nymphs inside the foam produced by these insects. However, the practical application of this predator depends on the development of efficient laboratory rearing protocols. In this study, it was found that the embryonic development of S. nigra is strongly influenced by abiotic factors, and maintaining the eggs between 20 and 30 °C with daily hydration is recommended to ensure high viability. For adults, an artificial diet based on yeast and honey proved adequate, allowing good survival, fecundity, and egg production, which represents an important advance for the mass rearing of this stage of the life cycle. On the other hand, larval development still represents the main challenge for large-scale production of the species. The alternative diets tested were not able to sustain the complete development of the larvae, and even with the use of natural prey, high mortality rates were observed under controlled conditions. These results indicate that the larvae depend on specific ecological conditions, possibly related to humidity, the foam produced by the spittlebug nymphs, and environmental interactions not yet reproduced in the laboratory, which limits, to date, the viability of mass rearing. In addition to the biological and applied aspects, a new species, Salpingogaster distincta sp. nov., morphologically close to S. nigra, was described, whose larvae were also found preying on spittlebugs. The morphological and molecular characterization of this new species expands the taxonomic knowledge of the group and highlights the still largely unexplored potential of the genus as a source of biological control agents. Overall, the results of this research demonstrate important advances in the rearing of adults and in understanding the factors that affect the early development of S. nigra, while also highlighting critical limitations in larval development. The discovery of a new predator species reinforces the potential of the genus Salpingogaster, indicating that, despite the challenges, these hoverflies represent a promising and sustainable alternative for the management of spittlebugs.