Syrphidae (Diptera) are a group of organisms that are considered important for the maintenance of the environment because they perform various ecological services, such as pollination, biological control, and decomposition. However, Syrphidae is still among the least studied Diptera families in the Neotropical Region due to the lack of specialists, along with the great diversity of behaviors among species and a large number of species. This study aimed to investigate the composition of adult syrphids in an environmental preservation area over two years and to verify the influence of meteorological conditions on the abundance, richness, and composition of the species collected. The sampling of adults was performed with passive traps and active searches in the Cerrado sensu stricto and Mata de Galeria phytophysiognomies between October 2018 and August 2020. In total, 442 specimens from 66 species of Syrphidae were collected. The genus Toxomerus had the highest number of specimens, and the most abundant species were T. lacrymosus (Bigot, 1884) and T. laenas (Walker, 1852). The Cerrado showed the highest abundance of syrphids, while richness was not significantly affected by any variable. In addition to the collection site, abundance was negatively affected by temperature and positively affected by the collection technique. For diversity, only the collection site had a significant effect. It was concluded that the phytophysiognomy as well as the environmental conditions influenced the diversity of this group. Implications for insect conservation: The results showed that very high temperatures negatively affected the number of specimens collected, suggesting a low ability to survive in warmer environments. Additionally, different phytophysiognomies showed differences in the diversity of insects from the family Syrphidae, and therefore, the preservation of both phytophysiognomies has the potential to assist in the maintenance of syrphid species and ensure the continuity of ecological services provided by these insects.

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