Effects of prey quality and predator body size on prey DNA detection success in a centipede predator
Effects of prey quality and predator body size on prey DNA detection success in a centipede predator
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DOI：
10.1111/mec.12654
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发表时间：
2014-08-01
影响因子：
4.9
通讯作者：
Scheu, S.
中科院分区：
文献类型：
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作者：
Eitzinger, B.;Unger, E. M.;Scheu, S.
捕食者的身体大小和猎物质量是驱动猎物选择和消费率的重要因素。这两个因素都可能影响基于PCR的肠道内容物分析的猎物检测成功率，可能导致过度或低估的摄食率。然而，实验证据很少。我们研究了蜈蚣捕食者的身体大小和猎物质量如何影响猎物DNA检测的成功。由于代谢率随着体型的增加而增加，我们假设大型捕食者的猎物DNA检测间隔会比小型捕食者短。此外，我们假设，高质量的猎物，定义为低的碳-氮比的猎物检测间隔将短于低质量的猎物，由于更快的同化。小型，中型和大型蜈蚣石属。（Lithobiidae，唇足目）喂弹尾目，并允许消化猎物长达168小时后喂养。为了验证我们的第二个假设，中型lithobiids喂养双翅目或蚯蚓。没有显着差异，在50%的猎物DNA检测成功的时间间隔为272 bp的猎物DNA片段被发现之间的捕食者大小组，表明身体大小不影响猎物DNA检测成功。食后检测间隔显着较短的蚯蚓和双翅目相比，弹尾目猎物，显然支持第二个假设。然而，诊断PCR的灵敏度不同的猎物类型，和定量PCR显示，目标DNA的浓度变化显着的猎物类型之间。这表明，在评估猎物质量对猎物DNA检测成功的影响时，需要考虑DNA浓度和检测灵敏度。
Predator body size and prey quality are important factors driving prey choice and consumption rates. Both factors might affect prey detection success in PCR-based gut content analysis, potentially resulting in over-or underestimation of feeding rates. Experimental evidence, however, is scarce. We examined how body size and prey quality affect prey DNA detection success in centipede predators. Due to metabolic rates increasing with body size, we hypothesized that prey DNA detection intervals will be shorter in large predators than in smaller ones. Moreover, we hypothesized that prey detection intervals of high-quality prey, defined by low carbon-to-nitrogen ratio will be shorter than in low-quality prey due to faster assimilation. Small, medium and large individuals of centipedes Lithobius spp. (Lithobiidae, Chilopoda) were fed Collembola and allowed to digest prey for up to 168 h post-feeding. To test our second hypothesis, medium-sized lithobiids were fed with either Diptera or Lumbricidae. No significant differences in 50% prey DNA detection success time intervals for a 272-bp prey DNA fragment were found between the predator size groups, indicating that body size does not affect prey DNA detection success. Post-feeding detection intervals were significantly shorter in Lumbricidae and Diptera compared to Collembola prey, apparently supporting the second hypothesis. However, sensitivity of diagnostic PCR differed between prey types, and quantitative PCR revealed that concentration of targeted DNA varied significantly between prey types. This suggests that both DNA concentration and assay sensitivity need to be considered when assessing prey quality effects on prey DNA detection success.