Potential novel hosts for the lily leaf beetle Lilioceris lilii Scopoli (Coleoptera: Chrysomelidae) in eastern North America

Abstract

Abstract 1. Introduced insects often incorporate native plants into their diets and might be expected to show a predilection for novel hosts that are phylogenetically related to their normal hosts. The lily leaf beetle, Lilioceris lilii (Coleoptera: Chrysomelidae), is an introduced pest of cultivated lilies. Oviposition behaviour, larval behaviour, and development of L. lilii was examined on a range of potential host plants, as well as on the normal host, Asiatic hybrid lilies Lilium sp.2. Neonate larval feeding behaviour was quantified on 15 food plant species: 10 from the Liliales, three from the Asparagales and two eudicots. Larvae fed plants closely related to the genus Lilium were more likely to initiate feeding, less likely to abandon their food leaf, and consumed more leaf area.3. In no‐choice tests, females oviposited on the novel hosts Lilium philadelphicum, Medeola virginiana, Clintonia borealis, Streptopus amplexifolius, and Polygonatum biflorum; however, all but L. philadelphicum received very few eggs. Non‐Lilium novel hosts were not used for oviposition when presented along with Asiatic lilies in choice tests.4. A single individual was reared to the adult stage on the novel host S. amplexifolius. Several larvae survived to the pupal stage on M. virginiana, although no adults emerged from those pupae. Larvae reared on the native wood lily L. philadelphicum performed equally well or better than on the Asiatic cultivar.5. Our results indicate that the lily leaf beetle poses a threat to native Liliaceae. Several native Lilium species, including L. philadelphicum, are threatened or endangered in certain jurisdictions throughout their range; these species should be monitored closely for colonisation by the beetle.