ABSTRACT

The role of generalist predators has long been considered an important component of mortality for many agricultural pests but can be difficult to quantify. We present the use of digital imaging as a means of both identifying key stink bug egg predators and measuring their relative impact on egg survivorship. Brown marmorated stink bug (BMSB), Halyomorpha halys and bagrada bug, Bagrada hilaris, two exotic stink bugs new to California, are now widely distributed throughout the state. A survey was conducted to identify resident natural enemies of their eggs. A field camera aided in the identification of arthropods attacking these eggs and their relative impact. Predation of BMSB eggs, which are naturally oviposited onto plant foliage, was less than for eggs of bagrada bug, which oviposit onto and into soil. The top ranked predators of BMSB eggs were the carabid Laemostenus complanatus (Coleoptera) the European earwig Forficula auricularia and ring-legged earwig Euborellia annulipes (Dermaptera), the oriental cockroach Blatta orientalis (Orthoptera), and the spider Trachelas spp. (Araneae). The two most common and important predators of bagrada bug were two ant species (Formicidae), Solenopsis xyloni and Monomorium ergatogyna, and species of Collembola (Entomobryidae). A Predation Index was developed to compare the relative importance of BMSB egg predators. Lastly, two striking, unanticipated results are reported: an apparent synergistic interaction between the spider Trachelas spp. and native ant M. ergatogyna in causing damage to sentinel eggs of BMSB, and the predaceous role for Collembola on bagrada bug sentinel eggs.

摘要

长期以来，通才捕食者的作用一直被认为是许多农业害虫死亡率的重要组成部分，但很难量化。我们提出了使用数字成像作为识别主要臭虫卵捕食者和测量它们对卵存活率的相对影响的一种手段。褐斑蝽 (BMSB)、Halyomorpha halys和 bagrada bug、Bagrada hilaris，两种新到加利福尼亚的奇异臭虫，现在广泛分布在全州。进行了一项调查，以确定它们卵的常驻天敌。现场摄像机有助于识别攻击这些卵的节肢动物及其相对影响。在植物叶子上自然产卵的 BMSB 卵的捕食量低于在土壤上和土壤中产卵的巴格拉达虫卵。BMSB 卵的顶级捕食者是 carabid Laemostenus complanatus (Coleoptera)、欧洲蜚蠊Forficula auricularia和环腿蜣螂 Euborellia annulipes (Dermaptera)、东方蟑螂Blatta orientalis (Orthoptera) 和蜘蛛Trachelasspp. （蜘蛛目）。Bagrada bug 的两种最常见和最重要的捕食者是两种蚂蚁（蚁科），Solenopsis xyloni和Monomorium ergatogyna，以及跳虫（Entomobryidae）。开发了一个捕食指数来比较 BMSB 蛋捕食者的相对重要性。最后，报告了两个惊人的、意想不到的结果：蜘蛛Trachelas spp 之间明显的协同相互作用。和本地蚂蚁M. ergatogyna对 BMSB 的哨兵卵造成损害，以及跳虫对巴格拉达虫哨兵卵的捕食作用。