Bistline-East Allison, Carey John G J, Colton Andrew, Day Michael F, Gormally Michael J
Applied Ecology Unit, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland.
Ryan Institute, National University of Ireland Galway, Galway, Ireland.
Environ Entomol. 2018 Dec 7;47(6):1632-1641. doi: 10.1093/ee/nvy155.
Marsh flies are a diverse family that provide valuable ecosystem services, including the biological control of mollusks that are agricultural pests and vectors of animal and human parasitic diseases. In addition, some species may serve as important ecological bioindicators. Despite the extensive research on this family, most have centered on larval diet and behavior, as this is the life stage primarily used for biological control; virtually nothing is known about the natural dietary components of adult marsh flies. Our study aimed to close this knowledge gap by examining the dietary range and preference of adult marsh fly species. Individual flies were provided with five food choices in cafeteria-style food choice trials, consisting of crushed snail, freshly killed slug, glucose solution, honey-yeast mixture (the standard laboratory rearing diet), or water. Sciomyzidae at family level displayed significant differences in food selection (P = 0.0212), with carbohydrates (honey-yeast and glucose solution) significantly preferred over protein options (mollusk tissue) or the water control (P < 0.001). This suggests that marsh flies may naturally maintain a carbohydrate-rich diet. Because many plants typical at field sites produce little or no nectar, a second experiment aimed to determine the source of these carbohydrates in nature. When presented with honeydew harvested from aphids (Hemiptera: Auchenorrhycha), Tetanocera elata Fabricius (Diptera: Sciomyzidae) individuals were observed to feed on dry honeydew and honeydew solution significantly more frequently than the water control (P < 0.001 and P = 0.01969, respectively), suggesting that honeydew may play an important role in adult marsh fly diet.
沼蝇是一个多样化的科，提供有价值的生态系统服务，包括对作为农业害虫以及动物和人类寄生虫病传播媒介的软体动物进行生物防治。此外，一些物种可能是重要的生态生物指示物种。尽管对这个科进行了广泛研究，但大多数研究都集中在幼虫的饮食和行为上，因为这是主要用于生物防治的生命阶段；而对于成年沼蝇的天然饮食成分几乎一无所知。我们的研究旨在通过研究成年沼蝇物种的饮食范围和偏好来填补这一知识空白。在自助式食物选择试验中，为每只苍蝇提供了五种食物选择，包括碾碎的蜗牛、刚杀死的蛞蝓、葡萄糖溶液、蜂蜜 - 酵母混合物（标准实验室饲养饲料）或水。沼蝇科在科级水平上食物选择存在显著差异（P = 0.0212），碳水化合物（蜂蜜 - 酵母和葡萄糖溶液）明显比蛋白质类食物（软体动物组织）或作为对照的水更受青睐（P < 0.001）。这表明沼蝇可能自然地保持富含碳水化合物的饮食。由于许多野外常见植物产生的花蜜很少或根本不产生花蜜，因此进行了第二项实验以确定这些碳水化合物在自然界中的来源。当给黄腹沼蝇（双翅目：沼蝇科）个体提供从蚜虫（半翅目：叶蝉亚目）采集的蜜露时，观察到它们取食干蜜露和蜜露溶液的频率明显高于作为对照的水（分别为P < 0.001和P = 0.01969），这表明蜜露可能在成年沼蝇的饮食中起重要作用。
