Seasonality of predatory insects (Diptera: Syrphidae and Asilidae) in pasture monoculture and silvopastoral systems from Southeast Brazil

• Published in: International journal of tropical insect science Vol. 41; no. 1; pp. 861 - 872
• Main Authors: Veríssimo, B. A., Auad, A. M., Oliveira, C. M., Paiva, I. G.
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.03.2021; Springer Nature B.V
• Subjects: Abundance; Asilidae; Biological control; Biomedical and Life Sciences; Climate change; Correlation analysis; Diptera; Entomology; Flies; Insects; Life Sciences; Monoculture; Original Research Article; Pasture; Pests; Predators; Seasonal distribution; Seasonal variations; Species; Syrphidae; Brazil; Environment; Forage; Hoverflies, robber flies, malaise traps
• ISSN: 1742-7592; 1742-7584; 1742-7592
• DOI: 10.1007/s42690-020-00276-8

In this long-term study we evaluated the diversity and seasonality of predatory insects (Diptera: Syrphidae and Asilidae) in Brachiaria decumbens monoculture and silvopastoral systems in Southeast Brazil. The study was conducted in Coronel Pacheco municipality, Minas Gerais state, Brazil, between February 2010 and January 2015. Insects were collected with malaise traps installed in both monoculture and silvopastoral systems. Specimen abundance, family diversity, seasonality assessed by circular analysis, the degrees of association between specimen number and climatic variables measured by Spearman’s correlation, and the constancy and similarities of Syrphidae and Asilidae were analyzed in the monoculture and silvopastoral systems. Eleven species of hoverflies (Diptera: Syrphidae) were collected, five and three of which were exclusive to the silvopasture and monoculture, respectively. The number of specimens within the monoculture was significantly greater than that in the silvopasture. Twenty-four species of robber flies (Diptera: Asilidae) were collected, two of which were exclusive to the monoculture and eight to the silvopasture. The abundance of robber flies in the silvopasture was not significantly different from that in the monoculture. Syrphidae diversity was greater in the monoculture and was not significantly different from robber fly family diversity. Circular analysis revealed seasonality, with the distribution grouped during dry periods for hoverflies and dispersed for robber flies. Most hoverflies and robber flies were accidental in each of the systems. Further studies on the capacity of these predator species to act as biological control agents of pasture pests are required. This study presents important and promising results for understanding the dynamics of the Syrphidae and Asilidae community in monoculture and silvopastoral systems in Brazil.