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.

中文翻译：

---

巴西东南部牧场单一栽培和林牧系统中捕食性昆虫（双翅目：蚜科和蛉科）的季节性

在这项长期研究中，我们评估了巴西东南部卧床臂虫单一栽培系统和林牧系统中捕食性昆虫（双翅目：蚜科和飞虱科）的多样性和季节性。该研究于 2010 年 2 月至 2015 年 1 月在巴西米纳斯吉拉斯州的 Coronel Pacheco 市进行。昆虫是通过在单一栽培和林牧系统中安装的不适捕集器收集的。在单一栽培和林牧系统中分析了标本丰度、家庭多样性、通过循环分析评估的季节性、标本数量与由 Spearman 相关性测量的气候变量之间的关联程度以及 Syrphidae 和 Asilidae 的稳定性和相似性。收集了 11 种食蚜蝇（双翅目：食蚜蝇科），其中五个和三个分别为林牧和单一栽培所独有。单一栽培中的标本数量明显多于林场中的标本数量。收集了 24 种强盗蝇（双翅目：Asilidae），其中两种专用于单一栽培，8 种专用于林场。林场中强盗苍蝇的数量与单一栽培中的数量没有显着差异。Syrphidae 多样性在单一栽培中更大，并且与强盗蝇科多样性没有显着差异。循环分析显示季节性，食蚜蝇的分布在干旱时期分组，而强盗苍蝇则分散。大多数食蚜蝇和强盗苍蝇在每个系统中都是偶然的。需要进一步研究这些捕食者物种作为牧草害虫生物防治剂的能力。这项研究为了解巴西单一栽培和林牧系统中 Syrphidae 和 Asilidae 群落的动态提供了重要和有希望的结果。