Plant architecture affects periodical cicada oviposition behavior on native and non‐native hosts

Abstract

Variation in plant quality provides a basis for oviposition site selection for a variety of insects. Of the plant traits that influence plant–insect interactions, plant architecture has received little attention despite its putative role in modulating oviposition behavior. In a common garden comprised of native and non‐native plant species, we assessed how host plant architecture and identity influenced the oviposition behavior of 17‐year periodical cicadas (Homoptera: Cicadidae: Magicicada). On each host, we quantified the availability of branches suitable for oviposition and compared those measures with the branches used by ovipositing cicadas. Using this approach, we determined how the structural attributes of plants (i.e. branch diameter, length and incline) affected oviposition site selection. We then related cicada oviposition preferences to offspring performance by quantifying egg hatching success. On each host species, cicadas selectively used broader and longer branches for oviposition, suggesting that branch architecture provides a basis for oviposition behavior irrespective of plant identity. Broader and longer branches were more abundant on native than on non‐native hosts in our study, contributing to greater oviposition loads among the native species. Egg hatching success was similar among native and non‐native hosts. However, it is possible that the use of native plants for oviposition could enhance offspring output because native hosts generally contained more viable eggs per egg nest and more egg nests per plant. While previous accounts of cicada oviposition preferences have focused on differences in oviposition loads among hosts, our evaluation of within‐host branch selection by ovipositing cicadas helps to clarify oviposition preferences at a higher resolution and demonstrates that plant architecture provides an important basis for oviposition behavior. Furthermore, because branch structure can differ substantially among host species, our results suggest that periodical cicadas may be sensitive to the changes in plant composition that often result from non‐native plant invasions.