SETTLEMENT AND BEHAVIOR IN RELATION TO FLOW AND SURFACE IN LARVAL BARNACLES, BALANUS-AMPHITRITE DARWIN

Behavior and settlement of laboratory-reared larval barnacles were examined with respect to age of larvae, type of surface (polystyrene and glass), and treatment of surface with settlement factor. Young cyprids were more discriminating in settlement than old cyprids. Young cyprids settled more on glass than on polystyrene. Young cyprids settled in higher percent on either polystyrene or glass in the presence of settlement factor. Settlement factor had no detectable effect on settlement of older cyprids. A rapid (2-10 min) quantitative assay for study of larval barnacle responses to surfaces was developed. The assay can be used to investigate molecular modifiers of larval barnacle behavior. Surfaces treated by adsorption of settlement factor from a 2.5 .mu.g/ml solution promoted reversible attachment by cyprids. Cyprids separated on the basis of their behavior were tested in settlement assays. In the absence of settlement factor, there were marked differences in percent settlement between classes. Addition of settlement factor to settlement assays did not affect settlement of certain behavior classes and increased settlement over 6-fold in others.