Kartzinel Tyler R, Pringle Robert M
Department of Ecology & Evolutionary Biology, Princeton University, 106A Guyot Hall, Princeton, NJ, 08544, USA.
Mol Ecol Resour. 2015 Jul;15(4):903-14. doi: 10.1111/1755-0998.12366. Epub 2015 Jan 14.
Understanding community assembly and population dynamics frequently requires detailed knowledge of food web structure. For many consumers, obtaining precise information about diet composition has traditionally required sacrificing animals or other highly invasive procedures, generating tension between maintaining intact study populations and knowing what they eat. We developed 16S mitochondrial DNA sequencing methods to identify arthropods in the diets of generalist vertebrate predators without requiring a blocking primer. We demonstrate the utility of these methods for a common Caribbean lizard that has been intensively studied in the context of small island food webs: Anolis sagrei (a semi-arboreal 'trunk-ground' anole ecomorph). Novel PCR primers were identified in silico and tested in vitro. Illumina sequencing successfully characterized the arthropod component of 168 faecal DNA samples collected during three field trips spanning 12 months, revealing 217 molecular operational taxonomic units (mOTUs) from at least nine arthropod orders (including Araneae, Blattodea, Coleoptera, Hemiptera, Hymenoptera, Isoptera, Lepidoptera and Orthoptera). Three mOTUs (one beetle, one cockroach and one ant) were particularly frequent, occurring in ≥50% of samples, but the majority of mOTUs were infrequent (180, or 83%, occurred in ≤5% of samples). Species accumulation curves showed that dietary richness and composition were similar between size-dimorphic sexes; however, female lizards had greater per-sample dietary richness than males. Overall diet composition (but not richness) was significantly different across seasons, and we found more pronounced interindividual variation in December than in May. These methods will be generally useful in characterizing the diets of diverse insectivorous vertebrates.
了解群落组装和种群动态通常需要详细的食物网结构知识。对于许多消费者来说，传统上要获得有关饮食组成的精确信息，需要牺牲动物或采用其他高度侵入性的程序，这在维持完整的研究种群与了解它们的食物之间产生了矛盾。我们开发了16S线粒体DNA测序方法，无需使用阻断引物即可识别广食性脊椎动物捕食者饮食中的节肢动物。我们证明了这些方法对于一种常见的加勒比蜥蜴的实用性，这种蜥蜴在小岛屿食物网的背景下已得到深入研究：沙氏变色蜥（一种半树栖的“树干-地面”变色蜥生态形态）。通过计算机模拟鉴定了新型PCR引物并进行了体外测试。Illumina测序成功地对在为期12个月的三次野外考察中收集的168份粪便DNA样本中的节肢动物成分进行了表征，揭示了至少九个节肢动物目（包括蜘蛛目、蜚蠊目、鞘翅目、半翅目、膜翅目、等翅目、鳞翅目和直翅目）的217个分子操作分类单元（mOTU）。三个mOTU（一种甲虫、一种蟑螂和一种蚂蚁）特别常见，在≥50%的样本中出现，但大多数mOTU不常见（180个，即83%，在≤5%的样本中出现）。物种积累曲线表明，体型二态性的两性之间饮食丰富度和组成相似；然而，雌性蜥蜴的样本饮食丰富度高于雄性。总体饮食组成（但不是丰富度）在不同季节有显著差异，并且我们发现12月的个体间差异比5月更明显。这些方法对于表征各种食虫脊椎动物的饮食将具有普遍用途。
