Allen Warwick J, Waller Lauren P, Barratt Barbara I P, Dickie Ian A
Bio-Protection Research Centre, School of Biological Sciences University of Canterbury Christchurch New Zealand.
Present address: Manaaki Whenua - Landcare Research 76 Gerald Street Lincoln 7608 New Zealand.
Ecol Evol. 2023 Aug 29;13(8):e10444. doi: 10.1002/ece3.10444. eCollection 2023 Aug.
Characterising plant-herbivore interactions is important to understanding the processes that influence community structure and ecosystem functioning. Traditional methods used to identify plant-herbivore interactions are being superseded by non-destructive molecular approaches that can infer interactions with greater resolution and accuracy from environmental DNA (e.g. faeces and regurgitate). However, few studies have compared the success of using different sample types and whether they provide similar or contrasting information about species' diet. Here we compared the success of DNA amplification and host plant species identification using restriction fragment length polymorphism (RFLP) applied to faecal and regurgitate samples collected from alpine grasshoppers Hutton during a grassland community mesocosm experiment. We found that DNA amplification success was 23% and 86% higher for faecal than regurgitate samples from female and male grasshoppers, respectively. In contrast, successful host plant identification using RFLP was 9% higher for regurgitate than faecal samples. The mean number of host plant species identified per sample (1.40) did not differ between sample types or grasshopper sexes. Of the 136 paired faecal-regurgitate samples, just 41% and 74% produced exactly or partially matching host plant identifications, respectively, indicating that different sample types provided complementary information about herbivore diet. Some plant species were more likely to be identified from faecal samples than expected by chance, and we found that this identification bias skewed towards plant species with higher investment in leaf tissue. We conclude that multiple sample types may be required to fully characterise an invertebrate herbivore species' diet.
表征植物与食草动物之间的相互作用对于理解影响群落结构和生态系统功能的过程至关重要。用于识别植物与食草动物相互作用的传统方法正被非破坏性分子方法所取代，这些方法可以从环境DNA（如粪便和反刍物）中以更高的分辨率和准确性推断相互作用。然而，很少有研究比较使用不同样本类型的成功率，以及它们是否提供关于物种饮食的相似或对比信息。在这里，我们比较了在草地群落中观实验期间，应用限制性片段长度多态性（RFLP）对从高山蝗虫哈顿采集的粪便和反刍物样本进行DNA扩增和宿主植物物种鉴定的成功率。我们发现，雌性和雄性蝗虫粪便样本的DNA扩增成功率分别比反刍物样本高23%和86%。相比之下，使用RFLP进行的宿主植物成功鉴定中，反刍物样本比粪便样本高9%。每个样本鉴定出的宿主植物物种平均数量（1.40）在样本类型或蝗虫性别之间没有差异。在136对粪便 - 反刍物样本中，分别只有41%和74%产生了完全或部分匹配的宿主植物鉴定结果，这表明不同的样本类型提供了关于食草动物饮食的互补信息。一些植物物种从粪便样本中被鉴定出来的可能性比随机预期的要高，并且我们发现这种鉴定偏差倾向于在叶片组织上投入更多的植物物种。我们得出结论，可能需要多种样本类型才能全面表征无脊椎食草动物物种的饮食。
