The hemlock woolly adelgid (Hemiptera: Adelgidae Adelges tsugae Annand) poses a serious threat to hemlocks in eastern North America, and ongoing research is focused on the identification and development of biological controls to protect and manage hemlock resources. Three predators native to the Pacific Northwest of North America that have been the focus of much research are Leucopis argenticollis (Zetterstedt), Leucopis piniperda (Malloch) (Diptera: Chamaemyiidae), and Laricobius nigrinus (Fender) (Coleoptera: Derodontidae). This study addresses the knowledge gap of adult Leucopis spp. emergence patterns, with comparisons to the timing of larval La. nigrinus drop for pupation. Adult Leucopis spp. emergence was observed in the lab from field-collected, adelgid-infested foliage from Washington state in 2019 and 2020. Adult Leucopis spp. were collected daily as they emerged from foliage collections and identified to species using morphological features; a subset was validated using DNA barcoding. Accumulated heating degree days were calculated to compare a standardized emergence timing across collections made at different locations and temperature regimes. The abundance of the two Leucopis spp. and of the combined Leucopis spp. and La. nigrinus varied among sites and years, and no species was consistently more abundant than the other. Evaluations of seasonal emergence trends of the three species determine the predator complex behaves in a temporally stratified and predictable way. Emergence of adult Le. argenticollis was observed first, followed by La. nigrinus larval drop, with Le. piniperda emerging at the end of larval drop, and finally a second emergence of Le. argenticollis.

中文翻译：

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Hemlock Woolly Adelgid 的生物控制：两种 Leucopis spp 成虫出现模式的影响。（双翅目：Chamaemyiidae）和 Laricobius nigrinus（鞘翅目：Derodontidae） 幼虫掉落

铁杉羊毛 adelgid (Hemiptera: Adelgidae Adelges tsugae Annand) 对北美东部的铁杉构成严重威胁，正在进行的研究集中在识别和开发生物控制以保护和管理铁杉资源。原产于北美太平洋西北部的三种捕食者是许多研究的重点，它们是白斑白斑（Zetterstedt）、松白斑（Malloch）（双翅目：Chamaemyiidae）和黑松鼠（Fender）（鞘翅目：Derodontidae）。本研究解决了成年白斑病菌的知识差距。出现模式，与幼虫 La. nigrinus 下降化蛹的时间进行比较。成虫 Leucopis spp。2019 年和 2020 年，在实验室中观察到从华盛顿州现场采集的、受腺藻侵染的树叶中出现。成年 Leucopis spp。每天从树叶收集中收集并使用形态特征识别物种；使用 DNA 条形码验证了一个子集。计算累积加热度天数以比较在不同位置和温度状态下收集的标准化出现时间。两种 Leucopis spp 的丰度。和组合的 Leucopis spp。和 La. nigrinus 因地点和年份而异，没有一个物种比其他物种更丰富。对这三个物种的季节性出现趋势的评估决定了捕食者复合体的行为以时间分层和可预测的方式。成人乐的出现。argenticollis 首先被观察到，其次是 La. nigrinus 幼虫下降，与 Le。piniperda在幼虫下降结束时出现，最后是Le的第二次出现。银颈。