Hydrilla verticillata is an aquatic weed that grows densely throughout the water column and is costly to manage. The hydrilla tip mining midge, Cricotopus lebetis, a potential augmentative biological control agent of hydrilla, feeds on the apical meristem preventing growth. The goal of this study was to quantify the influence of a predator (mosquitofish, Gambusia sp.) and a competitor (hydrilla leafcutter moth, Parapoynx diminutalis) and their interactions, on the ability of the midge to survive and feed on hydrilla. The first experiment involved six treatments established in 37.8 L tanks with combinations of the organisms, including larval C. lebetis. Survival to adult midge eclosion was significantly reduced in the presence of the predator but was unaffected by the competitor’s presence alone. Apical meristem damage was reduced when both the competitor and predator were present. The second experiment included four treatments with C. lebetis egg masses or larvae and the presence or absence of mosquitofish. Adding C. lebetis as eggs rather than as larvae increased midge survival in the absence of the predator. Midge survival was lower when larvae were added, but the predator had no additional effect. To facilitate successful establishment of the midge and control of hydrilla, high numbers of larvae should be released to overcome predation.

中文翻译：

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竞争和捕食对黑螈生存的影响及其作为黑螈潜在增强生物防治剂的成功

Hydrilla verticillata 是一种水草，在整个水柱中密集生长，管理成本高。黑藻尖端采矿蠓，Cricotopus lebetis，一种潜在的黑藻增强生物防治剂，以顶端分生组织为食，阻止生长。本研究的目的是量化捕食者（蚊鱼、Gambusia sp.）和竞争者（hydrilla Leafcutter moth、Parapoynx diminutalis）及其相互作用对蠓生存和以 hydrilla 为食的能力的影响。第一个实验涉及在 37.8 升水箱中建立的六种处理，其中包含生物体的组合，包括幼虫 C. lebetis。在捕食者存在的情况下，成年蠓羽化的存活率显着降低，但不受竞争者单独存在的影响。当竞争者和捕食者都在场时，顶端分生组织的损伤会减少。第二个实验包括用 C. lebetis 卵块或幼虫进行的四次处理以及蚊鱼的存在与否。在没有捕食者的情况下，将 C. lebetis 作为卵而不是幼虫添加可以提高蠓的存活率。添加幼虫后，蠓的存活率较低，但捕食者没有额外的影响。为了促进蠓的成功建立和控制黑藻，应释放大量幼虫以克服捕食。添加幼虫后，蠓的存活率较低，但捕食者没有额外的影响。为了促进蠓的成功建立和控制黑藻，应释放大量幼虫以克服捕食。添加幼虫后，蠓的存活率较低，但捕食者没有额外的影响。为了促进蠓的成功建立和控制黑藻，应释放大量幼虫以克服捕食。