Reference: Biol. Bull. 176: 73-78. (April, 1989) Induction of Swimming in Stomphia (Anthozoa: Actiniaria) by Imbricatine, a Metabolite of the Asteroid Dermasterias imbricata J. K. ELLIOTT 1 *, D. M. ROSS 1 f . C. PATHIRANA 2 , S. MIAO 2 . R. J. ANDERSEN 2 -*, P. SINGER 3 , W. C. M. C. KOKKE 1 3 , AND W. A. AVER 3 Department of Zoology, Biological Sciences Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2E9; -Departments of Chemistry and Oceanography, University of British Columbia, Vancouver, British Columbia, Canada V6T 1 W5; and ^Department of Chemistry. University of Alberta, Edmonton. Alberta. Canada T6G 2E9 Abstract. Imbricatine, a benzyltetrahydroisoquinoline alkaloid released by Dermasterias imbricata, has been tested for its ability to elicit escape responses in prey of the asteroid. Bioassays demonstrated that imbricatine is very effective at causing the detachment and swimming response in Stomphia coccinea, but is less effective at elic-iting the same response in S. didemon. Two fragments of imbricatine. the benzyltetrahydroisoquinoline and 3-methyl histidine portions, were relatively inactive. Im-bricatine did not elicit detachment behavior in either Ur-ticina ( = Tealia ) piscivora or Epiactis lisbethae. The lack of comparable biochemical data for other escape and avoidance behaviors precludes any firm explanations of general patterns of chemical recognition of predators and non-predators by marine invertebrates. Introduction Many marine organisms exhibit escape and avoidance responses to chemicals released by their predators. The best documented of these behaviors are the responses of Received 24 June 1988: accepted 20 December 1988. * Present address: Department of Biological Science. Florida State University, Tallahassee, FL 32306. ' Deceased. D. M. Ross initiated this project and sustained interest in the work for over 1 5 years. This paper is dedicated to him. * Author to whom reprint requests should be addressed. 'Present address: Smith Kline & French Laboratories, King of Prus-sia. PA 19406. a wide variety of invertebrate prey species to chemicals secreted by predatory asteroids and mollusks (Feder, 1967; Edmunds, 1974; Mackie and Grant, 1974; Mayo and Mackie, 1976; Phillips, 1975. 1977, 1978: Sloan. 1980; Watanabe. 1983: Harvey el a!.. 1987). Despite the large number of studies that have demonstrated chemi-cal recognition of predators by their prey, "relatively lit-tle information is available concerning the nature of the substances responsible" (Mackie and Grant, 1974). To understand the chemical basis for these behaviors both qualitative and quantitive information is needed. How-ever, the chemical structure of the active substances and the quantities required to elicit the behaviors have been elucidated in only a few cases (Turner et al, 197 1; Har-vey, 1985; Harvey el al, 1987). This makes it difficult to answer many general questions about the nature of chemical recognition in these interactions. One of the best studied and most dramatic escape re-sponses of a marine invertebrate is the detachment and swimming behavior of Stomphia (S. coccinea and 5. di-demon) in response to certain species of asteroids and the nudibranch Aeolidia papillosa. This escape response has interested scientists since it was first described by Yentsch and Pierce ( 1955) and has resulted in a wide va-riety of studies on different aspects of the interaction: be-havioral (Robson, 196 la; Ross, 1965a,b, 1967a,b, 1979; Ross and Sutton, 1964a, 1967a, b), neurophysiological (Hoyle, 1960; Robson. 1 96 Ib; Ross and Sutton, 1964b; Lawn, 1976, 1980), morphological (Sund. 1958; Rob-73
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