Invasive species are among the most important environmental threats to biodiversity and ecosystem function. Invasive plant success is due in part to release from natural enemies2\, however, such invasives represent novel resources that may be utilized by insect herbivores via ecological fitting, in which pre-adapted native species colonize the invasive, or evolutionary adaptation, wherein native herbivores evolve preference and performance traits to this novel resource. Communities of native herbivores feeding on invasive plants may increase over time due to these processes.
Amur honeysuckle, Lonicera maackii,and autumn olive, Elaeagnus umbellata, are both highly invasive shrubs well-established throughout Eastern North America. Escape from enemies has likely facilitated the success and spread of both species. Records of insect herbivores using these invasive plants in their introduced range are sparse and focused on mobile taxa, which may be transient.
Results/Conclusions
Caterpillars are important herbivores that exhibit a wide range of host plant specificity. My preliminary lepidopteran surveys in Southwest Ohio suggest that a diverse community of caterpillars (>60 spp.) have colonized these invasive plants. Our lepidopteran surveys were conducted May-September during the 2018 and 2019 field season in both edge and interior habitats. All collected caterpillars were reared in the lab to confirm the host plan, as well as species identification.
Sampling was primarily opportunistic, yet, preliminary comparisons suggest that caterpillar communities on both invasive plants are as rich and diverse as those seen on native species. The caterpillar communities found on these invasive plants are mostly composed of generalists, however, the species diversity of these communities is quite different. We’ve found that there are at least 30 different caterpillar species feeding specifically on E. umbellata. The number of caterpillar species that are specifically feeding on L. maackii is higher, around 40 species.
Our data preliminary data suggests that the caterpillar community on well-established invasive plant species is rich. Both when compared to that seen on native plants, as well as other well-established invasives.