Abstract Arundo donax (L.), commonly known as giant reed, is an invasive weed in riparian habitats worldwide. The chloropid fly Cryptonevra nigritarsis Duda infests young shoots of A. donax in its native range and has been considered for a long time as a potential biological control agent. This study was designed to investigate the biology and field ecology of C. nigritarsis and document its impact on A. donax. Populations of A. donax were monitored in ten field sites for a full year and sticky traps were used to assess C. nigritarsis abundance. Young A. donax shoots with signs of infestation were dissected monthly, and a DNA-based diagnosis method was developed to assess the prevalence of C. nigritarsis among the larvae and pupae collected. Finally, a manipulative experiment was performed to evaluate the impact of water stress on A. donax vulnerability to C. nigritarsis. Results showed that C. nigritarsis is likely to be a multivoltine species overwintering mainly as pupa. Only 6.3% of the A. donax shoots monitored were infested and the overall prevalence of C. nigritarsis among the larvae and pupae collected was 54.3%. C. nigritarsis was found in shoots of all diameters and was the predominant species in very thin and very thick shoots. Thicker shoots had a greater probability of infestation by chloropid flies in general. The manipulative experiment showed that mortality of A. donax shoots in the presence of C. nigritarsis was higher is water-stressed plants, but overall shoot mortality and infestation were low. These results shed light on some important aspects on the biology and ecology of C. nigritarsis and help in evaluating its potential as a biological control agent.

中文翻译：

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Cryptonevra nigritarsis Duda 的生物学、生态学和影响，这是一种针对巨型芦苇 Arundo donax 的潜在生物控制剂

摘要 芦竹 (Arundo donax, L.)，俗称巨芦苇，是一种栖息于全球河岸栖息地的入侵杂草。叶绿蝇 Cryptonevra nigritarsis Duda 在其原生范围内侵染 A. donax 的幼芽，长期以来一直被认为是一种潜在的生物防治剂。本研究旨在调查 C. nigritarsis 的生物学和野外生态学，并记录其对 A. donax 的影响。全年在 10 个现场地点对 A. donax 的种群进行了监测，并使用粘性陷阱来评估 C. nigritarsis 的丰度。每月解剖具有侵染迹象的年轻 A. 竹笋，并开发了一种基于 DNA 的诊断方法来评估收集的幼虫和蛹中黑曲霉的患病率。最后，进行了一个操作实验来评估水分胁迫对 A. donax 对 C. nigritarsis 的脆弱性。结果表明，C. nigritarsis 很可能是一种主要以蛹越冬的多生种。只有 6.3% 的被监测的芦笋枝条被侵染，并且在所收集的幼虫和蛹中黑曲霉的总体流行率为 54.3%。C. nigritarsis 存在于所有直径的枝条中，并且是非常薄和非常厚的枝条中的主要物种。一般而言，较厚的枝条被叶绿蝇侵染的可能性更大。操作性实验表明，在 C. nigritarsis 存在的情况下，A. nigritarsis 存在的芦荟枝条死亡率较高，是水分胁迫的植物，但总体枝条死亡率和侵染率较低。这些结果揭示了 C. nigritarsis 生物学和生态学的一些重要方面，并有助于评估其作为生物防治剂的潜力。