Induction of Swimming inStomphia(Anthozoa: Actiniaria) by Imbricatine, a Metabolite of the AsteroidDermasterias imbricata

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 eliciting the same response in S. didemon. Two fragments of imbricatine, the benzyltetrahydroisoquinoline and 3-methyl histidine portions, were relatively inactive. Imbricatine did not elicit detachment behavior in either Urticina (= 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.