Lilioceris lilii

(Scopoli, 1763)

lily leaf beetle, scarlet lily beetle, red lily beetle

The lily leaf beetle, Lilioceris lilii, is a leaf beetle in the Chrysomelidae native to Asia and now widespread across Eurasia and North America. It is a herbivore of lilies and related plants in the family Liliaceae, feeding on leaves, stems, buds, and flowers. Both and larvae cause significant damage to plants, with larvae capable of complete defoliation. The has become a serious pest in gardens and natural areas where lilies occur, including threatening native and endangered Lilium species in North America.

Lilioceris lilii by the Smithsonian. Used under a CC0 license.Lilioceris lilii by the Smithsonian. Used under a CC0 license.Lilioceris lilii by the Smithsonian. Used under a CC0 license.

Pronunciation

How to pronounce Lilioceris lilii: /ˌlɪliəˈsɛrɪs ˈlɪliˌaɪ/

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Identification

are distinctive with bright scarlet-red and pronotum contrasting with black , legs, and underside. Body length averages 7–8 mm, with females slightly larger than males. Larvae are orange to reddish with black heads, bearing a characteristic fecal shield—a mass of excrement carried on the back. The combination of red-and-black adult coloration and the larval fecal shield distinguishes this from other chrysomelids on Liliaceae.

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Habitat

Closely associated with plants in the Liliaceae, including garden plantings, naturalized , and wild populations of native lilies. overwinter in soil or sheltered locations. Larvae develop on above-ground portions of host plants and pupate in soil.

Distribution

Native to Asia; naturalized throughout Eurasia from Siberia to Morocco and the United Kingdom to China. Introduced to North America: first recorded in Canada (Quebec) in 1943, in the United States (Massachusetts) in 1992. Now established in New England states, Canadian provinces of Quebec, Ontario, Nova Scotia, and Manitoba, and expanding westward including Washington State.

Seasonality

with one per year. emerge from in spring, feed on plants, and oviposit beginning in late spring. Larvae present through summer, pupating in soil. Adults enter winter in autumn.

Diet

herbivore feeding on leaves, stems, buds, and flowers of Liliaceae. Primary include Lilium (cultivated Asiatic hybrids, native species including L. philadelphicum), Fritillaria species, and Cardiocrinum giganteum. Larvae feed exclusively on host foliage; feed on all above-ground plant parts.

Host Associations

  • Lilium - primary includes cultivated Asiatic hybrids and native
  • Fritillaria - primary
  • Cardiocrinum giganteum - primary giant lily
  • Lilium philadelphicum - native wood lily; larvae perform equally well or better than on cultivated varieties
  • Medeola virginiana - novel oviposition observed; some larvae survived to pupal stage but no
  • Clintonia borealis - novel oviposition observed in no-choice tests
  • Streptopus amplexifolius - novel single individual reared to in laboratory
  • Polygonatum biflorum - novel oviposition observed in no-choice tests

Life Cycle

. Overwinters as in soil or sheltered microhabitats. Spring followed by feeding and mating. Females oviposit in linear rows on undersides of leaves, averaging 130 per female in field conditions (up to 1,900 under laboratory conditions). Embryonic development averages 8.5 days. Larvae pass through four instars over approximately 16 days, carrying a fecal shield throughout development. occurs in soil, lasting approximately 18 days. New adults emerge in summer, feed, then enter for winter.

Behavior

Larvae exhibit a distinctive defensive : they accumulate and carry excrement (fecal shield) on their backs, which deters . and larvae are voracious feeders, capable of completely defoliating plants. Adults use odor-mediated orientation to locate hosts and conspecifics; diapaused females are attracted to intact host plant odor and to combinations of host plant and odor. Pre- males avoid odor from beetle-infested plants.

Ecological Role

Herbivore and agricultural/garden pest. In its native range, are influenced by including Tetrastichus setifer, Lemophagus pulcher, and others. In North America, the has expanded its range to include native Liliaceae , posing conservation threats to rare and endangered lilies. Subject to efforts using introduced European parasitoids.

Human Relevance

Significant pest of ornamental lilies in gardens and horticultural operations. Threatens native lily including of conservation concern. Subject to management through chemical control, manual removal, and using introduced . Has been identified as a risk associated with international plant trade, contributing to calls for improved biosecurity measures.

Similar Taxa

Sources and further reading