Nontarget Effects of Host-Specific Biocontrols: Direct and Indirect Effects of Biocontrols that Subsidize Native Consumers

众所周知，消费者在食物网中的间接影响在生态系统中很重要，但这一知识尚未很好地整合到应用领域，如生物制剂控制杂草。引入外来昆虫作为生物防治剂是控制入侵植物的一种日益普遍的策略，只要防治剂是宿主特异性的，就被认为是生态安全的。然而，即使是宿主特有的病原体也可能被本地物种消耗，从而影响食物网的其余部分。这项研究将检验一种外来瘿蝇对鹿鼠种群的间接影响，这种外来瘿蝇是为了控制一种入侵的草物种而引入的，鹿鼠是北美西部许多草原上昆虫和种子的主要捕食者，也是Sin Nombre汉坦病毒的主要载体，汉坦病毒导致人类致命的汉坦病毒肺综合征。研究目的是通过对草地小块地去除瘿蝇的扰动实验，量化瘿蝇补贴对鹿鼠种群的直接影响，并测量间接影响，包括汉坦病毒的流行、种子捕食、本地植物的萌发和招募以及本地昆虫的丰度。这项研究将通过提供一种更有效地从生物防治计划中过滤潜在有害昆虫的方法，推动生物防治领域的发展。此外，将向区域卫生当局传播汉坦病毒信息，以帮助制定管理准则，以减少与胆蝇介导的汉坦病毒流行率增加有关的人类健康风险。

The indirect effects of consumers in food webs are known to be important in ecological systems, but this knowledge has not been well integrated into applied fields such as weed control by biological agents. The introduction of exotic insects as biological control agents is an increasingly common strategy employed for the control of invasive plants and is thought to be ecologically safe so long as the control agents are host-specific. However, even host-specific agents may be consumed by native species and so impact the rest of the food web. This research will examine the indirect effects of an exotic gall fly, introduced to control an invasive grass species, on populations of deer mice that are key predators of insects and seeds in many western North American grasslands, and are the primary vectors for the Sin Nombre hantavirus, which causes the deadly hantavirus pulmonary syndrome in humans. Research goals are to conduct a perturbation experiment by removing gall flies from grassland plots in order to quantify the direct effect of gall fly subsidies on deer mouse populations, and measure indirect effects, which include the prevalence of the hantavirus, seed predation, germination and recruitment of native plants, and abundance of native insects. This research will advance the field of biological control by providing a means of more effectively filtering potentially hazardous insects from biocontrol programs. Additionally, hantavirus information will be disseminated to regional health authorities to help develop management guidelines to reduce human health risks associated with gall fly-mediated increases in the prevalence of hantavirus.