Monocropping elevates many insects to the status of economic pests. In these agroecosystems, non-crop habitats are sometimes deployed as trap crops to reduce pest damage. This environmentally friendly alternative to pesticides can be particularly fitting when dealing with native invaders that may be afforded legal protection or enjoy public sympathy as is the case for the ground wētā Hemiandrus sp. ‘promontorius’ (Orthoptera) in New Zealand. However, this approach requires knowledge of the insects’ diet to select the most appropriate plant species for trap cropping. Here, ingested plant DNA in the faeces of wētā was analysed to help develop strategies for mitigating its damage in New Zealand vineyards. DNA was extracted from faeces of wētā collected from six different vineyards over four seasons. Using a DNA metabarcoding approach, we amplified the rbcL gene region and sequenced the amplicons on an Illumina MiSeq platform. The identity of plants in the diet of this insect was determined by comparing the sequences generated with those available in the GenBank database and cross-checking the results with a database of plants known to be present in New Zealand. A total of 47 plant families and 79 genera were detected. Of the genera identified, Vitis, Poa, Festuca, Anthoxanthum, Anagallis, Camelina, Epilobium, Menyanthes, Pedicularis, Urtica, Garrya, Pinus and Tilia were the major ones (i.e. they were present in more than 50% of the faecal samples). The composition of the above plant taxa in faecal materials was significantly different between collection sites or dates, except for Menyanthes. The occurrence of the latter was significantly different between collection sites. These results indicate that effectively mitigating wētā damage to vines requires the use of a diverse mix of plant species for trap cropping as wētā seem to be highly generalist in their feeding behaviour even when plant diversity is relatively low.

中文翻译：

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在通才害虫的粪便中鉴定植物DNA，以提供诱捕剂种植策略

单作将许多昆虫提升为经济害虫的地位。在这些农业生态系统中，有时将非作物生境用作陷阱作物，以减少虫害。当与可能受到法律保护或受到公众同情的本地入侵者打交道时，这种环保的农药替代品尤为合适，例如地面wētāHemiandrussp。“ promontorius”（直翅目）在新西兰。但是，这种方法需要了解昆虫的饮食，以选择最合适的植物种诱捕。在这里，分析了wētā粪便中摄取的植物DNA，以帮助制定减轻其在新西兰葡萄园中的破坏的策略。在四个季节中，从六个不同葡萄园收集的wētā粪便中提取DNA。使用DNA元条形码技术，我们扩增了rbcL基因区域，并在Illumina MiSeq平台上对扩增子进行测序。通过将产生的序列与GenBank数据库中可用的序列进行比较，并与已知存在于新西兰的植物数据库进行交叉核对，可以确定该昆虫饮食中植物的身份。共检测到47个植物科和79属。辨认，属葡萄，早熟禾，高羊茅，黄花，Anagallis，亚麻荠，柳叶菜，睡菜，马先蒿，荨麻，Garrya，松和椴是主要的（即粪便样本中有50％以上存在）。除薄荷叶外，上述植物类群在粪便中的成分在采集地点或日期之间也存在显着差异。后者的发生在收集地点之间明显不同。这些结果表明，要有效减轻葡萄藤对葡萄的损害，即使植物多样性相对较低，由于葡萄进食行为似乎具有很高的通用性，因此需要使用多种植物来诱捕葡萄。