Abstract

The southern pine beetle (SPB) Dendroctonus frontalis Zimmermann, is the most important insect pest of pines in the southeastern United States, with outbreaks often resulting in thousands of hectares of pine mortality. Natural enemies and competitors have been cited as significant regulators of SPB populations and, therefore, outbreaks. A recent outbreak on the Homochitto National Forest (NF) in Mississippi provided an opportunity to undertake a case study comparing population fluctuations of SPB, its major predator Thanasimus dubius, and its competitors, Ips bark beetles. Trap catches of all three were tracked through the course of the outbreak on the Homochitto NF as well as in two other forests with low or no SPB activity. The number of predators collected initially increased on the Homochitto NF in response to the SPB outbreak, but their impact on reducing infestation numbers was unclear. Numbers of Ips trapped were similar across all three forests, indicating that other factors were regulating SPB populations. The outbreak only lasted a single year, and its brevity likely limited the availability of host resources for natural enemy and competitor populations. Additional studies are warranted to explore the mechanisms affecting the extent and duration of SPB outbreaks, such as active forest management.

中文翻译：

---

竞争者和捕食者对短暂的南方松树甲虫暴发的反应：一个案例研究

摘要

南方松甲虫（SPB）Dendroctonus frontalis Zimmermann是美国东南部最重要的松树虫害，爆发常常导致成千上万公顷的松树死亡。天敌和竞争对手被认为是SPB人口的重要监管者，因此成为暴发暴发。最近在密西西比州的Homochitto国家森林（NF）爆发提供了一个进行案例研究的机会，比较了SPB，其主要捕食者Thanasimus dubius及其竞争对手Ips的种群波动。树皮甲虫。整个暴发过程中，在Homochitto NF以及其他两个SPB活性较低或没有SPB活性的森林中，都追踪了所有三个陷阱的捕获量。响应SPB爆发，最初在Homochitto NF上收集的捕食者数量有所增加，但是它们对减少感染数量的影响尚不清楚。在所有三个森林中，被困的Ips数量相似，表明其他因素正在调节SPB种群。疫情仅持续了一年，其短暂性可能限制了天敌和竞争对手种群的宿主资源。必须进行其他研究来探索影响SPB爆发程度和持续时间的机制，例如积极的森林管理。