Assessing zinc tolerance in two butterfly species: consequences for conservation in polluted environments

1. Zinc is a widespread pollutant released from industrial combustion, auto- mobile residue, and mining. Zinc accumulates in soils and mobilises into plant tissue where it may be consumed to potentially toxic levels by leaf feeding insects, including developing pollinators. 2. While zinc tolerance thresholds have been previously assessed in insect pollinators, most observations are limited to model organisms and pest species. We lack understand- ing of zinc tolerance in insects of conservation concern. 3. We assess dietary zinc tolerance of developing caterpillars from wild populations of the monarch butterfly (Danaus plexippus), a species of conservation concern, whose caterpillars are commonly exposed to elevated dietary zinc exposure in milkweed plants along roadsides. We contrast monarch zinc tolerance with that of cabbage white butterfly caterpillars (Pieris rapae), a non-native pest species. Tolerance was assessed by rearing caterpillars on artificial diets containing varyin...1. 锌是一种广泛分布的污染物，其来源包括工业燃烧、汽车残余物及采矿活动。锌可在土壤中累积，并迁移进入植物组织；取食该类植物叶片的昆虫（包括处于发育阶段的传粉昆虫）摄入锌后，体内锌含量可能达到潜在毒性水平。 2. 尽管此前已有针对昆虫传粉者的锌耐受阈值的研究，但多数观测结果仅局限于模式生物与害虫类群。目前学界对具有保育价值的昆虫的锌耐受能力仍缺乏足够认知。 3. 本研究针对具有保育价值的君主斑蝶（Danaus plexippus）野生种群的发育阶段幼虫，评估其膳食锌耐受能力；该物种的幼虫在路边的马利筋植物上取食时，通常会暴露于升高的膳食锌水平中。本研究将君主斑蝶的锌耐受能力与非本土害虫物种菜粉蝶（Pieris rapae）的幼虫进行对比。耐受能力通过在含有不同（原文此处内容未完整）的人工饲料上饲养幼虫以完成评估。