Department of Horticulture, Oregon State University, 4017 Agricultural and Life Sciences Building, Corvallis, OR, 97331, USA.
Embrapa Algodão, Rua Oswaldo Cruz 1143, Campina Grande, PB, 58428-095, Brazil.
Sci Rep. 2019 Mar 5;9(1):3592. doi: 10.1038/s41598-019-40256-8.
Most organisms must ingest water to compensate for dehydration. In parasitic wasps, the importance of water and the behaviors driving its consumption are poorly understood. Here, we describe a water-intake strategy of Pachycrepoideus vindemmiae, a parasitoid of spotted-wing drosophila (SWD, Drosophila suzukii). Longevity measurements indicated that P. vindemmiae benefits from drinking water and from host-feeding on the water-rich hemolymph of SWD pupae. After exposing wasps to different water regimens, we observed increased host-feeding in water-deprived wasps despite honey availability. This resulted in greater SWD mortality because the host-feeding process killed the pupae, and because wasps that engaged in greater host-feeding parasitized more hosts. Behavioral observations showed that the host-feeding time of water-deprived wasps doubled compared to water-fed individuals. Host-feeding did not affect parasitoid offspring mortality. We conclude that P. vindemmiae benefits from ingesting water and that it host-feeds on SWD pupae as a water-intake strategy. These are interesting findings not only because water has rarely been reported as a critical nutrient for adult parasitoids, but especially because preying for the purpose of hydration is not a common strategy in nature. This strategy enhances parasitoid survival and reproduction, with positive consequences for its host-killing capacity and potential as a biocontrol agent.
大多数生物必须摄入水分以弥补脱水。在寄生蜂中，水的重要性及其消耗行为还了解甚少。在这里，我们描述了一种寄生蜂——长尾潜叶蝇姬小蜂（Pachycrepoideus vindemmiae）的取食策略，该蜂寄生在斑点翅果蝇（SWD，Drosophila suzukii）的蛹上。寿命测量表明，长尾潜叶蝇姬小蜂从饮水和取食富含水分的 SWD 蛹血淋巴中受益。在将寄生蜂暴露于不同的水分处理后，我们观察到尽管有蜂蜜供应，但缺水的寄生蜂会增加对寄主的取食。这导致更多的 SWD 死亡，因为取食过程会杀死蛹，而且取食更多的寄生蜂会寄生更多的寄主。行为观察表明，缺水的寄生蜂的取食时间是饮水寄生蜂的两倍。取食不会影响寄生蜂后代的死亡率。我们得出结论，长尾潜叶蝇姬小蜂从饮水中受益，并以取食 SWD 蛹作为一种取食策略。这些发现不仅有趣，因为水很少被报道为成年寄生蜂的关键营养物质，而且特别是因为为了补水而捕食并不是自然界中常见的策略。这种策略提高了寄生蜂的生存和繁殖能力，对其杀死宿主的能力和作为生物防治剂的潜力具有积极影响。
