Estación Experimental Agropecuaria (EEA) Concordia, Instituto Nacional de Tecnología Agropecuaria (INTA), Buenos Aires, Entre Ríos, Argentina.
Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Valencia, Spain.
J Anim Ecol. 2019 Jun;88(6):915-926. doi: 10.1111/1365-2656.12982. Epub 2019 Apr 10.
Biological control has traditionally simplified the view of trophic relationships between herbivorous pests and their natural enemies in agriculture. The success or failure of this pest management strategy is still mainly attributed to the ability of a few key natural enemies to suppress the pest density. For example, successful regulation of the California red scale (Aonidiella aurantii), a key citrus pest, is generally credited to specific parasitoids of the Aphytis genus. Currently, research is revealing how herbivore regulation in agroecosystems can be alternatively achieved with a greater number of trophic associations within the system. The goals of the present study were as follows: i) to unravel species-specific trophic links between A. aurantii and its natural enemies in citrus agroecosystems, and ii) to assess their contribution to control of A. aurantii. Predation and parasitism of this herbivorous pest were assessed through exclusion experiments. Species-specific trophic links between this herbivorous pest and its natural enemies were studied using gut-content analysis of field-collected predators employing prey-specific DNA molecular markers. Relative predation rates of the species involved in A. aurantii regulation were estimated. Predation was found to be the main biotic component of A. aurantii mortality, causing reductions of more than 75% in recently settled cohorts. Aonidiella aurantii DNA was detected in the digestive system of 11 species of predators. Generalist and stenophagous predators, mainly associated with other citrus pests such as aphids, proved to be the most important biological control agents of this pest. Complex trophic relationships, such as apparent competition between two key citrus pests, were revealed. The present study highlights the role of predation as biotic mortality factor of key pests in perennial agroecosystems, wherein it is a rich complex of indigenous or naturalized generalist predators that are primarily responsible for this mortality. The results herein presented may therefore offer another perspective on the biological control of one of the key world-wide citrus pests, at least in those regions where specific parasitoids are not able to successfully regulate the scale populations.
生物防治在传统上简化了农业中植食性害虫与其天敌之间的营养关系的观点。这种害虫管理策略的成败仍然主要归因于少数关键天敌抑制害虫密度的能力。例如，加利福尼亚红蚧（Aonidiella aurantii）的成功调控，这种柑橘的主要害虫，通常归因于 Aphytis 属的特定寄生蜂。目前，研究揭示了在农业生态系统中，通过系统内更多的营养联系，如何替代地实现植食者的调控。本研究的目的如下：i）阐明柑橘农业生态系统中 A. aurantii 与其天敌之间的种特异性营养联系，ii）评估它们对 A. aurantii 控制的贡献。通过排除实验评估了这种植食性害虫的捕食和寄生作用。使用基于猎物特异性 DNA 分子标记的野外采集捕食者的肠道内容物分析，研究了这种植食性害虫与其天敌之间的种特异性营养联系。估计了参与 A. aurantii 调控的物种的相对捕食率。发现捕食是 A. aurantii 死亡率的主要生物组成部分，导致最近定居的虫群减少了 75%以上。在 11 种捕食者的消化系统中检测到 A. aurantii 的 DNA。证明了兼性和专性捕食者，主要与其他柑橘害虫（如蚜虫）有关，是这种害虫的最重要的生物防治剂。揭示了两种关键柑橘害虫之间明显的竞争等复杂的营养关系。本研究强调了捕食作为多年生农业生态系统中关键害虫的生物死亡因素的作用，在这些生态系统中，主要负责这种死亡率的是本土或归化的、具有丰富多样性的一般捕食者。因此，本研究结果至少在那些特定寄生蜂无法成功调控蚧虫种群的地区，为一种关键的世界性柑橘害虫的生物防治提供了另一种视角。
