Sheppard S K, Henneman M L, Memmott J, Symondson W O C
Cardiff School of Biosciences, Cardiff University, P.O.Box 915, Cardiff CF10 3TL, UK.
Mol Ecol. 2004 Jul;13(7):2077-88. doi: 10.1111/j.1365-294X.2004.02216.x.
Abstract Alien invertebrate predators have been introduced to Hawaii to control pests, particularly in lowland areas where most crops are grown. We developed techniques for assessing the impact of these predators on native food webs in relatively pristine upland areas where, it was hypothesized, few lowland predators might be found. Predator densities were assessed along transects within the Alakaii Swamp on Kaua'i. The most numerous alien biocontrol agents found were Halmus chalybeus (Coccinellidae), a species known to feed on Lepidoptera eggs. Laboratory experiments were conducted using two genera of endemic Lepidoptera, Scotorythra and Eupithecia (Geometridae), that are of considerable conservation value, the former because of its recent speciation across Hawaii, the latter for its unique predatory larvae. Techniques were developed for detecting Lepidoptera DNA within the guts of alien predators using prey-specific PCR primers. General primers amplified fragments of the mitochondrial cytochrome oxidase I gene from beetles and Lepidoptera. The sequences were aligned and used successfully to design target-specific primers for general detection of the remains of Geometridae and for particular species, including Scotorythra rara and Eupithecia monticolans. DNA fragments amplified were short [140-170 base pairs (bp)], optimizing detection periods following prey ingestion. Trials using the introduced biocontrol agent Curinus coeruleus (Coccinellidae) demonstrated detection of Lepidoptera DNA fragments = 151 bp in 85-100% of beetles after 24 h digestion of an early instar larva. This study provides a framework for future use of molecular gut analysis in arthropod conservation ecology and food web research with considerable potential for quantifying threats to endemic species in Hawaii and elsewhere.
摘要外来无脊椎动物捕食者已被引入夏威夷以控制害虫，尤其是在大多数作物种植的低地地区。我们开发了一些技术，用于评估这些捕食者对相对原始的高地地区本地食物网的影响，据推测，在这些高地地区可能很少能发现低地捕食者。沿着考艾岛阿拉凯伊沼泽内的样带评估了捕食者的密度。发现的数量最多的外来生物防治剂是蓝斑扁背叶甲（瓢虫科），这是一种已知以鳞翅目昆虫卵为食的物种。使用具有相当保护价值的两个地方性鳞翅目属进行了实验室实验，即刺蛾属和尤尺蛾属（尺蛾科），前者因其最近在夏威夷各地形成新物种，后者因其独特的捕食性幼虫。开发了利用猎物特异性聚合酶链反应引物检测外来捕食者肠道内鳞翅目昆虫DNA的技术。通用引物扩增了来自甲虫和鳞翅目昆虫的线粒体细胞色素氧化酶I基因片段。对这些序列进行了比对，并成功用于设计目标特异性引物，以普遍检测尺蛾科昆虫的残骸以及特定物种（包括稀刺蛾和山地尤尺蛾）的残骸。扩增的DNA片段较短[140 - 170个碱基对（bp）]，优化了猎物摄入后的检测周期。使用引入的生物防治剂蓝艳扁角叶甲（瓢虫科）进行的试验表明，在早期幼虫消化24小时后，85 - 100%的甲虫中检测到了长度 = 151 bp的鳞翅目昆虫DNA片段。本研究为未来在节肢动物保护生态学和食物网研究中使用分子肠道分析提供了一个框架，在量化对夏威夷及其他地区特有物种的威胁方面具有相当大的潜力。
