Data from: A molecular diagnostic tool for the preliminary assessment of host-parasitoid associations in biological control programmes for a new invasive pest

Evaluation of host-parasitoid associations can be tenuous using conventional methods. Molecular techniques are well-placed to identify trophic links and resolve host-parasitoid associations. Establishment of the highly invasive Brown Marmorated Stink Bug, Halyomorpha halys (Hemiptera: Pentatomidae) outside Asia has prompted interest in the use of egg parasitoids (Hymenoptera: Scelionidae) as biological control agents. However, little is known regarding their host ranges. To address this, a DNA barcoding approach was taken wherein general PCR primers for Scelionidae and Pentatomidae were developed to amplify and sequence >500-bp products within the DNA barcoding region of the Cytochrome Oxidase I (COI) gene that would permit identification of key players in this association. Amplification of DNA from Pentatomidae and Scelionidae was consistent across a broad range of taxa within these families, and permitted detection of Scelionidae eggs within H. halys 1h following oviposition. In laboratory assays, amplification and sequencing of DNA from empty, parasitized eggs was successful for both host (100% success) and parasitoid (50% success). When applied to field-collected, empty egg masses the primers permitted host identification in 50 – 100% of the eggs analyzed, and yielded species-level identifications. Parasitoid identification success ranged from 33 – 67% among field-collected eggs, with genus-level identification for most specimens. The inability to obtain species-level identities for these individuals is due to the lack of coverage of this taxonomic group in public DNA sequence databases; this situation is likely to improve as more species are sequenced and recorded in these databases. These primers were able to detect and identify both pentatomid host and scelionid parasitoid in a hyperparasitized egg mass, thereby clarifying trophic links otherwise unresolved by conventional methodology.

采用传统方法评估寄主与寄生蜂的类群关联时，往往难以得到可靠的鉴定结果。分子技术则十分适合识别营养联系、厘清寄主与寄生蜂的分类关联。高入侵性物种褐纹椿象（Halyomorpha halys，半翅目（Hemiptera）：蝽科（Pentatomidae））在亚洲以外地区的定殖，引发了学界对以卵寄生蜂（膜翅目（Hymenoptera）：缘腹细蜂科（Scelionidae））作为生物防治剂的研究兴趣，但目前对这类寄生蜂的寄主范围仍所知甚少。为此本研究采用DNA条形码（DNA barcoding）技术，针对缘腹细蜂科与蝽科设计通用聚合酶链式反应（PCR）引物，扩增并测序细胞色素氧化酶I（Cytochrome Oxidase I, COI）基因条形码区域内长度超过500bp的片段，从而实现该类群关联中关键物种的鉴定。该引物对两个科内多个类群的DNA扩增效果稳定，且可在褐纹椿象产卵后1小时内检测到其体内的缘腹细蜂卵。实验室测定结果显示，对已被寄生的空卵进行DNA扩增与测序，寄主样本的检测成功率达100%，寄生蜂样本的成功率为50%。将该引物应用于野外采集的空卵块时，50%~100%的待测卵可成功鉴定出寄主物种，并获得物种水平的分类鉴定结果；寄生蜂的鉴定成功率为33%~67%，多数样本可鉴定至属级水平。无法获得这些样本的物种级鉴定结果，是因为公共DNA序列数据库中缺乏该类群的参考序列数据；随着更多物种被测序并上传至此类数据库，这一现状将得到有效改善。该引物还可在重寄生卵块中同时检测并鉴定出蝽科寄主与缘腹细蜂科寄生蜂，厘清了传统方法无法解析的营养联系。