Invertebrate Behavior and Ecology

Three projects neared completion during 1980-8l: Steroid saponins, chemicals which are thought to elicit defensive behavior by many marine invertebrates, were isolated directly from seawater surrounding living specimens of two species of seastar, Pycnopodia helianthoides and Patiria miniata. The total amount of saponin released by equal wet weights of these two seastars is similar, but structural details of specific saponins may differ. Two other projects dealt with the defensive responses of certain prey to predators. One of these (with Marina Chiarappa) investigated the defensive responses of limpets to predatory flatworms. The other project was an investigation of the responses of two stenotopic limpets, Collisella instabilis and Notoacmea insessa, two seastar predators. In addition to the research described above revision of Between Pacific Tides has begun. Numerous photographs and collections will be taken at BML to support this work.