Severns Paul M, Guzman-Martinez Melinda
Department of Plant Pathology, University of Georgia, Athens, GA 30602, USA.
Insects. 2021 Mar 15;12(3):246. doi: 10.3390/insects12030246.
New plant pathogen invasions typified by cryptic disease symptoms or those appearing sporadically in time and patchily in space, might go largely unnoticed and not taken seriously by ecologists. We present evidence that the recent invasion of (Dermateaceae) into the Pacific Northwest USA, which causes foliar necrosis in the fall and winter on (plantain), the primary (non-native) foodplant for six of the eight extant Taylor's checkerspot butterfly populations (, endangered species), has altered eco-evolutionary foodplant interactions to a degree that threatens butterfly populations with extinction. Patterns of butterfly, larval food plant, and disease development suggested the ancestral relationship was a two-foodplant system, with perennial spp. supporting oviposition and pre-diapause larvae, and the annual supporting post-diapause larvae. Plantain, in the absence of disease, provided larval food resources throughout all butterfly life stages and may explain plantain's initial adoption by Taylor's checkerspot. However, in the presence of severe disease, plantain-dependent butterfly populations experience a six-week period in the winter where post-diapause larvae lack essential plantain resources. Only , which is rare and competitively inferior under present habitat conditions, can fulfill the post-diapause larval feeding requirements in the presence of severe disease. However, a germination timing experiment suggested to be suitably timed for only Washington Taylor's checkerspot populations. The recent invasion by appears to have rendered the ancestrally adaptive acquisition of plantain by Taylor's checkerspot an unreliable, maladaptive foodplant interaction.
以隐秘的疾病症状为特征或在时间上零星出现、在空间上分布不均的新植物病原体入侵，可能在很大程度上未被生态学家注意到，也未受到重视。我们提供的证据表明，最近（皮盘菌科）入侵美国太平洋西北部，导致秋季和冬季（车前草）叶片坏死，而车前草是现存八个泰勒细纹蝶种群中六个种群（一种濒危物种）的主要（非本地）食草植物，这种入侵已经在一定程度上改变了生态进化的食草植物相互作用，威胁到蝴蝶种群的灭绝。蝴蝶、幼虫食草植物和疾病发展的模式表明，其祖先关系是一种双食草植物系统，多年生的（某种植物）支持产卵和滞育前幼虫，一年生的（另一种植物）支持滞育后幼虫。在没有（某种疾病）的情况下，车前草在蝴蝶的所有生命阶段都提供幼虫食物资源，这可能解释了泰勒细纹蝶最初对车前草的选择。然而，在严重（某种疾病）存在的情况下，依赖车前草的蝴蝶种群在冬季会经历六周的时间，滞育后幼虫缺乏必需的车前草资源。只有（另一种植物），在目前的栖息地条件下很稀少且竞争力较弱，才能在严重（某种疾病）存在的情况下满足滞育后幼虫的取食需求。然而，一项发芽时间实验表明，（另一种植物）仅对华盛顿泰勒细纹蝶种群的时间安排合适。最近（某种植物）的入侵似乎使泰勒细纹蝶在祖先时期适应性地获取车前草的行为变成了一种不可靠的、适应不良的食草植物相互作用。
