■粪甲虫提供许多重要的生态系统服务,包括粪便分解,病原体控制,土壤通气,和二次种子传播。然而,大多数粪便甲虫的生物学仍然未知。对自然饮食的研究很少,部分原因是以前的研究集中在选择或吸引力实验上,从动物园动物容易接近的粪便类型,农场动物,或人类。这边,自然食物网中的许多链接肯定被错过了。在这项工作中,我们的目的是建立一个使用DNA肠道条形码分析粪甲虫自然饮食的协议。
■首先,在实验室中测试了从六种不同类型的哺乳动物粪便中提取肠道内容物DNA和扩增12srDNA的可行性。然后,我们使用12srDNA引物将该方法应用于厄瓜多尔和德国陷阱陷阱中捕获的甲虫。对于厄瓜多尔采样中捕获的粪便甲虫的子集,我们还使用了16srDNA引物,看看这些引物是否会增加我们可以识别的物种数量。我们预测了使用肠道饱腹度扩增DNA的可能性,DNA浓度,PCR引物,收集方法,和甲虫物种作为优势分析的预测变量。根据肠道条形码,我们为两个野外地点(厄瓜多尔和德国)建立了粪甲虫-哺乳动物网络,并分析了网络特异性水平.
■我们成功地从粪便甲虫肠道内容物中扩增了128个样本的哺乳动物DNA,其中包括Pantheraonca(美洲虎)和Pumaconcolor(puma)等著名物种。DNA扩增的总成功率为53%。扩增成功的最佳预测因子是肠道饱腹度和DNA浓度,表明通过专注于完整的甲虫可以提高成功率。哺乳动物粪便甲虫网络与纯随机网络模型不同,并显示出中等程度的网络专业化(H2\':厄瓜多尔=0.49;德国=0.41)。
■我们在这里提出了一种从粪甲虫中提取和扩增肠内容DNA的可靠方法。通过DNA参考文库鉴定哺乳动物粪便,我们创造了哺乳动物粪-粪甲虫营养网络。与以前的方法相比,这具有优势,因为我们清点了粪便甲虫的天然哺乳动物粪便资源,而不是使用人工哺乳动物诱饵。我们的结果显示,德国的专业化水平比预期的要高,啮齿动物的DNA比预期的要多,这表明所提出的方法提供了对哺乳动物粪-粪甲虫网络的更详细的见解。此外,该方法可以应用于许多生态系统中的哺乳动物监测。
UNASSIGNED: Dung beetles provide many important ecosystem services, including dung decomposition, pathogen control, soil aeration, and secondary seed dispersal. Yet, the biology of most dung beetles remains unknown. Natural diets are poorly studied, partly because previous research has focused on choice or attraction experiments using few, easily accessible dung types from zoo animals, farm animals, or humans. This way, many links within natural food webs have certainly been missed. In this work, we aimed to establish a protocol to analyze the natural diets of dung beetles using DNA gut barcoding.
UNASSIGNED: First, the feasibility of gut-content DNA extraction and amplification of 12s rDNA from six different mammal dung types was tested in the laboratory. We then applied the method to beetles caught in pitfall traps in Ecuador and Germany by using 12s rDNA primers. For a subset of the dung beetles caught in the Ecuador sampling, we also used 16s rDNA primers to see if these would improve the number of species we could identify. We predicted the likelihood of amplifying DNA using gut fullness, DNA concentration, PCR primer, collection method, and beetle species as predictor variables in a dominance analysis. Based on the gut barcodes, we generated a dung beetle-mammal network for both field sites (Ecuador and Germany) and analyzed the levels of network specificity.
UNASSIGNED: We successfully amplified mammal DNA from dung beetle gut contents for 128 specimens, which included such prominent species as Panthera onca (jaguar) and Puma concolor (puma). The overall success rate of DNA amplification was 53%. The best predictors for amplification success were gut fullness and DNA concentration, suggesting the success rate can be increased by focusing on beetles with a full gut. The mammal dung-dung beetle networks differed from purely random network models and showed a moderate degree of network specialization (H2\': Ecuador = 0.49; Germany = 0.41).
UNASSIGNED: We here present a reliable method of extracting and amplifying gut-content DNA from dung beetles. Identifying mammal dung via DNA reference libraries, we created mammal dung-dung beetle trophic networks. This has benefits over previous methods because we inventoried the natural mammal dung resources of dung beetles instead of using artificial mammal baits. Our results revealed higher levels of specialization than expected and more rodent DNA than expected in Germany, suggesting that the presented method provides more detailed insights into mammal dung-dung beetle networks. In addition, the method could have applications for mammal monitoring in many ecosystems.