Specialist herbivore performance on introduced plants during native host decline

Ash (Fraxinus spp.) is in rapid decline across the northeastern USA due to the invasive emerald ash borer (Agrilus planipennis Fairmaire). Three recently co-occurring confamilial species may serve as alternative larval host plants for ash-reliant Lepidoptera. These prospective hosts are non-native shrubs often planted in managed suburban landscapes and are sometimes invasive or naturalized in North America. Given the imminent decline of ash trees, we considered potential downstream effects on insect herbivores historically specialized on ash foliage. We measured the performance of three ash-specialist hawkmoths (Lepidoptera: Sphingidae) on native white ash (Fraxinus americana L.) and alternative host plants: common lilac (Syringa vulgaris L.), weeping forsythia (Forsythia suspensa (Thunb.) Vahl), and European privet (Ligustrum vulgare L.). We found the non-native host plants provided varied support for larval survival to pupation, with biomass and growth rate affected differently by bot..., ,