Flower attractiveness and fitness effects on a dipteran pest and its parasitoids for conservation biological control

Flower addition is commonly used worldwide to benefit parasitoids and improve conservation biological control of pests. However, biological control enhancement via flower addition depends on the responses of both parasitoid and pest species to flower resources and on flower attractiveness. Here, we experimentally evaluated the effects of two Apiaceae flowering species (Conium maculatum and Coriandrum sativum) with respect to those of water, honey and no resource treatments on longevity and survival of the leafminer Liriomyza huidobrensis adults and two himenopteran parasitoids (Chrysocharis flacilla and Phaedrotoma scabriventris. We also examined the attractiveness of both flower species to the leafminer and one of the parasitoid species. Consumption of flower resources increased longevity and survival of the three insect species with respect to water and no resource treatments. Honey effects on longevity were similar to or even higher than those of flowers, depending on the insect species, whereas water only increased the longevity of P. scabriventris in relation to no resource treatments. In attractiveness trials, parasitoids, but not leafminers, preferred C. maculatum flowers. Our findings indicate both plant species have potential as floral resources in biological control since two parasitoids species benefited from flowers. However, these flowering species must be cautiously considered because L. huidobrensis also improved its fitness when provided with both floral resources. The present work highlights the need to simultaneously study parasitoid and herbivore food needs and flower attractiveness, especially in dipteran pests, in order to achieve a successful biological control.

开花植物增补（flower addition）在全球范围内被广泛应用，以助力寄生性天敌昆虫，并提升害虫保护生物防治（conservation biological control）的效果。然而，通过开花植物增补实现的生防增效效果，取决于寄生性天敌与害虫类群对花类资源的响应，以及花材的引诱活性。
本研究通过室内实验，评估了两种伞形科（Apiaceae）显花植物——毒参（*Conium maculatum*）与芫荽（*Coriandrum sativum*）——的相关效应，并设置清水、蜂蜜及无资源对照处理，探究其对潜叶蝇（leafminer）南美斑潜蝇（*Liriomyza huidobrensis*）成虫，以及两种膜翅目（hymenopteran）寄生蜂：*Chrysocharis flacilla*与*Phaedrotoma scabriventris*的寿命与存活情况的影响。此外，本研究还检测了这两种显花植物对南美斑潜蝇及其中一种寄生蜂的引诱活性。
相较于清水与无资源对照处理，取食花类资源可显著提升三种供试昆虫的寿命与存活率。就寿命提升效果而言，蜂蜜与花类资源相当，甚至在部分昆虫类群中更优；而清水仅相较于无资源处理，可提升*Phaedrotoma scabriventris*的寿命。
在引诱活性试验中，寄生蜂而非潜叶蝇，更偏好毒参*Conium maculatum*的花朵。
本研究结果表明，这两种显花植物均可作为生物防治配套花类资源，因为两种寄生蜂均可从花类资源中获益。然而，在应用这两种开花植物时需谨慎，因为南美斑潜蝇在获取花类资源后，其适合度也得到了提升。
本研究强调，若要实现高效成功的生物防治，需同时探究寄生性天敌与植食性害虫的食物需求，以及花材的引诱活性，针对双翅目（dipteran）害虫的相关研究尤需重视。