Does the periodical cicada,Magicicada septendecim,prefer to oviposit on native or exotic plant species?

Abstract 1. In 2004, Brood X of the periodical cicada (Magicicada spp.) emerged in Delaware. Extensive suburban development and concomitant planting of exotic species has occurred since the previous emergence of Brood X in 1987. 2. Exotic species could suffer extensive damage during years of cicada emergences if they are preferred for oviposition. Alternately, a shortage of suitable plant hosts may negatively affect remaining cicada populations. 3. We determined if the periodical cicada, Magicicada septendecim, preferred to oviposit on native or exotic woody plant species. Potential hosts were divided into three groups and planted in a randomised design near a likely source of cicadas. The first group, Natives, included 15 species native to Delaware. The second group, Non‐natives, included 15 exotic species that had a native congener represented in the Native group. The final group, Aliens, included 13 exotic species that did not have a native congener. 4. Based on observations of 428 plants, cicadas were more likely to oviposit on Natives or Non‐natives, which did not differ from each other in this measure, than on Aliens. Non‐natives had more oviposition holes per metre than Natives, which had more holes per metre than Aliens. The likelihood of stem flagging was lowest on Alien species; the percentage of the total plant that flagged was greatest for Natives. Plant morphology also influenced host preference and likelihood of flagging. 5. Taking plant morphology into consideration, we speculate that the evolutionary history between periodical cicadas and potential hosts is an important component of host preference.