The text below is grayed out because it is not intended to be read. It is a necessarily imperfect OCR of the original and is only used by a search engine.
Journal of the Lepidopterists Society 38(3), 1984, 192-193
HOST SHIFT OF ECPANTHERIA DEFLORATA (ARCTIIDAE) FROM AN ANGIOSPERM TO A LIVERWORT
Kevin C. Spencer, Larry R. Hoffman and David S. Seigler
Department of Plant Biology, University of Illinois, Urbana, Illinois 61801
ABSTRACT. A population of Ecpantheria deflorata Fabricius (Lepidoptera: Arcti-idae) was discovered in W. Indiana feeding on Conocephalum conicum (Marchantiales: Marchantiaceae), a liverwort. The normal hosts of Ecpantheria in the study area are two species of Plantago, and the shift to Conocephalum has occurred despite major differences in host plant chemistry.
Ecpantheria deflorata Fabricius is an arctid moth which has been reported to feed on a number of unrelated species in North America (Tietz, 1972). These include Brassica oleracea L. (Brassicaceae), He-lianthus decapetalus L. (Asteraceae), Robinia pseudocacacia L. (Fa-baceae), Euphorbia heterophylla L. and Ricinus communis L. (Eu-phorbiaceae), Persea americana Mill. (Lauraceae), Phytolacca ameri-cana L. (Phytolaccaceae), Salix sp. (Salicaceae), Viola sp. (Violaceae) and Plantago rugellii Dec. and P. lanceolata L. (Plantaginaceae).
In the Portland Arch Nature Preserve, Fountain Co., Indiana, we found that Plantago rugellii and P. lanceolata serve as the major host plants for E. deflorata.
We observed, however, that a number of larvae were grazing exclusively on Conocephalum conicum L. (Hepaticae), especially in the fall of the year. This liverwort forms large mats on sheer rockfaces and is very abundant at Portland Arch. Few other lepidopterans are known to feed on bryophytes (see Tuskes & Smith, 1984), and not many are known from other lower plants (e.g., Euptychia on a lycopsid—Singer et al., 1971). Several larvae of various instars were reared on C. conicum in the laboratory and pupated and emerged normally.
We consider this host shift to be of interest because of the great difference in secondary chemistry between C. conicum and the angio-sperm hosts. The chemistry of Conocephalum has been reviewed (Markham & Porter, 1978; Spencer, 1979) and the plant has been found to contain a large array of mono- and sesquiterpenoids, including up to 0.6% dry weight ( + ) — bornyl acetate, a monoterpene existing in opposite chirality to that found in higher plants (Asakawa et al., 1976). Some liverwort terpenoids have been shown to inhibit feeding in Lepidoptera (Wada & Munakata, 1971). The major chemical constituents of Plantago are iridoid glycosides (Jensen et al., 1975).
We speculate that some larvae have shifted from Plantago to Co-
Volume 38, Number 3
193
nocephalum primarily due to the close proximity of infested individuals of Plantago to Conocephalum covered rocks and to the similar texture of the two plants.
As we have observed a population of Ecpantheria to be present on Conocephalum consistently for over 10 years, and given the unique chemistry of hepatics which has probably kept lepidopteran herbivores in general from utilizing them as host plants, we feel that this host shift represents a major event in the population biology of Ecpantheria. This may prove to be a useful system for studying population differentiation across chemical barriers and may represent an incipient spe-ciation event.
Acknowledgments
We thank Drs. J. G. Sternburg, G. P. Waldbauer and G. L. Godfrey for confirming our insect identification. Vouchers of plant specimens are deposited in the University of Illinois Herbarium.
Thanks are due especially to M. Berenbaum for helpful criticism.
Literature Cited
Asakawa, Y., M. Toyota & T. Aratani. 1976. ( + )-Bornyl acetate from Conocephalum conicum. Proc. Bryol. Soc. Japan 1:155-157.
Jensen, S. R., B. J. Nielsen & R. Dahlgren. 1975. Iridoid compounds, their occurrence and systematic importance in the angiosperms. Bot. Not. 128:148-180.
Markham, K. R. & L. J. Porter. 1978. Chemical constituents of the bryophytes. Pp. 182-272, in L. Reinhold, J. B. Harborne & T. Swain (eds.). Progress in Phytochem-istry, Vol. 5. Pergamon Press, N.Y.
Singer, M. C, P. R. Ehrlich & L. E. Gilbert. 1971. Butterfly feeding on lycopsid. Science 172:1341-1342.
Spencer, K. C. 1979. The chemical constituents of the Hepaticae. Phytochemical Bulletin 12:4-19.
TlETZ, H. M. 1972. An Index to the Described Life Histories, Early Stages and Hosts of the Macrolepidoptera of the Continental United States and Canada, Vol. 1. Allyn Museum of Entomology, Sarasota, Florida, 1041 p.
Tuskes, P. M. & N. J. Smith. 1984. The life history and behavior of Epimartyria pardella (Micropterigidae). J. Lepid. Soc. 38:40-46.
Wada, K. & K. Munakata. 1971. Insect feeding inhibitors in plants. III. Feeding inhibitory activity of terpenoids in plants. Agr. Biol. Chem. 35:115-118.