Oxitec Limited, 71 Milton Park, Oxford OX14 4RX, UK.
BMC Biol. 2012 Jun 19;10:51. doi: 10.1186/1741-7007-10-51.
The olive fruit fly, Bactrocera oleae, is the major arthropod pest of commercial olive production, causing extensive damage to olive crops worldwide. Current control techniques rely on spraying of chemical insecticides. The sterile insect technique (SIT) presents an alternative, environmentally friendly and species-specific method of population control. Although SIT has been very successful against other tephritid pests, previous SIT trials on olive fly have produced disappointing results. Key problems included altered diurnal mating rhythms of the laboratory-reared insects, resulting in asynchronous mating activity between the wild and released sterile populations, and low competitiveness of the radiation-sterilised mass-reared flies. Consequently, the production of competitive, male-only release cohorts is considered an essential prerequisite for successful olive fly SIT.
We developed a set of conditional female-lethal strains of olive fly (named Release of Insects carrying a Dominant Lethal; RIDL®), providing highly penetrant female-specific lethality, dominant fluorescent marking, and genetic sterility. We found that males of the lead strain, OX3097D-Bol, 1) are strongly sexually competitive with wild olive flies, 2) display synchronous mating activity with wild females, and 3) induce appropriate refractoriness to wild female re-mating. Furthermore, we showed, through a large proof-of-principle experiment, that weekly releases of OX3097D-Bol males into stable populations of caged wild-type olive fly could cause rapid population collapse and eventual eradication.
The observed mating characteristics strongly suggest that an approach based on the release of OX3097D-Bol males will overcome the key difficulties encountered in previous olive fly SIT attempts. Although field confirmation is required, the proof-of-principle suppression and elimination of caged wild-type olive fly populations through OX3097D-Bol male releases provides evidence for the female-specific RIDL approach as a viable method of olive fly control. We conclude that the promising characteristics of OX3097D-Bol may finally enable effective SIT-based control of the olive fly.
油橄榄果蝇，Bactrocera oleae，是商业橄榄生产中的主要节肢动物害虫，对全球橄榄作物造成广泛破坏。目前的控制技术依赖于化学杀虫剂的喷洒。不育昆虫技术（SIT）提供了一种替代的、环保的和种特异性的种群控制方法。尽管 SIT 在其他桔小实蝇害虫上非常成功，但以前对橄榄蝇的 SIT 试验产生了令人失望的结果。关键问题包括实验室饲养的昆虫昼夜交配节律的改变，导致野生和释放的不育种群之间的交配活动不同步，以及辐射不育大量饲养的苍蝇的竞争力低。因此，生产有竞争力的、仅雄性的释放群体被认为是成功实施橄榄蝇 SIT 的一个必要前提。
我们开发了一套油橄榄蝇的条件性雌性致死品系（命名为释放携带显性致死的昆虫；RIDL®），提供了高度穿透性的雌性特异性致死、显性荧光标记和遗传不育。我们发现，领先品系 OX3097D-Bol 的雄性 1）与野生橄榄蝇具有强烈的性竞争力，2）与野生雌蝇表现出同步的交配活动，3）诱导对野生雌蝇再交配的适当抗性。此外，我们通过一项大型原理验证实验表明，每周向笼养野生型橄榄蝇稳定种群中释放 OX3097D-Bol 雄性，可以导致种群迅速崩溃并最终灭绝。
观察到的交配特征强烈表明，基于释放 OX3097D-Bol 雄性的方法将克服以前橄榄蝇 SIT 尝试中遇到的关键困难。尽管需要现场确认，但通过 OX3097D-Bol 雄性释放抑制和消除笼养野生型橄榄蝇种群提供了证据，证明雌性特异性 RIDL 方法是一种可行的橄榄蝇控制方法。我们得出结论，OX3097D-Bol 的有希望的特性最终可能使基于 SIT 的有效控制橄榄蝇成为可能。
