Non-native congeneric trees are poor-quality host plants for a larval Lepidopteran

In managed ecosystems, cultivated plant diversity is a collection of
native and introduced species composed of varying plant origins across
scales: locally native, non-locally native, and non-native. Non-local and
non-native plant species may be ill-suited as host plants for locally
native insects. Yet, we lack information on the population- and
individual-level consequences of introduced plants to phytophagous
insects. Promethea moth (Callosomia promethea) is a Lepidopteran species
regionally specialized to Prunus in the Northeastern USA. Here, we used a
rearing experiment to compare Promethea caterpillar performance on 14
different Prunus host plants commonly found naturally and in horticulture
and two non hosts. Across all measures, P. serotina supported the highest
survival, fastest growth, and largest larval biomass. We found little
difference between locally native and non-local Prunus across most
measures; however, few non-native Prunus supported living larvae to the
fifth instar, and surviving larvae had reduced growth and biomass. Our
results indicate that non-native congeners are poor replacements for
locally native tree species in supporting specialized Lepidoptera.
However, non-local, regionally-native species in cultivation may serve as
adequate, albeit suboptimal, host plants. These results further our
understanding of how selection for plant traits or species impacts
biodiversity in novel and managed ecosystems.