Mercury (Hg) is a global pollutant that affects biota in remote settings due to atmospheric deposition of inorganic Hg, and its conversion to methylmercury (MeHg), the bioaccumulating and toxic form. Characterizing biotic MeHg is important for evaluating aquatic ecosystem responses to changes in Hg inputs. Aquatic insects possess many qualities desired for MeHg biomonitoring, but are not widely used, largely because of limited information regarding percentages of total mercury (THg) composed of MeHg (i.e., MeHg%) in various taxa. Here, we examine taxonomic, spatial, and seasonal variation in MeHg% of stream-dwelling predator and primary-consumer insects from nine streams in the Adirondack region (NY, USA). Predator MeHg% was high (median 94%) and did not differ significantly among five taxa. MeHg% in selected dragonflies (the most abundant predators, Odonata: Aeshnidae and Libellulidae) exhibited little seasonal and spatial variation, and THg concentration was strongly correlated with aqueous (filtered) MeHg (FMeHg; r_s = 0.76). In contrast, MeHg% in primary consumers—shredders (northern caddisflies [Trichoptera: Limnephilidae]) and scrapers (flathead mayflies [Ephemeroptera: Heptageniidae]), were lower (medians 52% and 35%, respectively), and differed significantly between taxa, among sites, and seasonally. Correlations of THg with FMeHg were weak (shredders, r_s = 0.45, p = 0.09) or not significant (scrapers, p = 0.89). The higher MeHg% of predators corresponded with their higher trophic positions (indicated by nitrogen stable isotopes). Results suggest obligate predators hold the most promise for the use of THg as a surrogate for MeHg biomonitoring with aquatic insects within the Adirondack region.

汞（Hg）是一种全球性污染物，由于无机Hg在大气中的沉积及其转化为甲基汞（MeHg）的生物累积和有毒形式，因此会影响偏远地区的生物群。表征生物MeHg对于评估水生生态系统对汞输入变化的响应非常重要。水生昆虫具有MeHg生物监测所需的许多质量，但并未得到广泛使用，主要是因为有关各种分类中由MeHg组成的总汞（THg）百分比（即MeHg％）的信息有限。在这里，我们研究了来自阿迪朗达克地区（美国纽约州）的九种溪流中居住于河流的捕食者和主要消费者昆虫的MeHg％的分类，空间和季节变化。捕食者的MeHg％较高（中位数为94％），在五个分类群中没有显着差异。_s  = 0.76）。相比之下，主要消费者中的MeHg％（切碎机（北鳞甲虫[Trichoptera：Limnephilidae]）和刮板机（flat头黄f [Ephemeroptera：Heptageniidae]）的甲基汞含量较低（中位数分别为52％和35％），并且各分类单元之间存在显着差异网站之间和季节性。THg与FMeHg的相关性较弱（粉碎机，r _s  = 0.45，p = 0.09）或不显着（刮板，p = 0.89）。捕食者中较高的MeHg％与它们较高的营养位置相对应（以氮稳定同位素表示）。结果表明，专职捕食者最有可能将THg用作对阿迪朗达克地区水生昆虫进行MeHg生物监测的替代物。