THE TENACITY OF ELMINIUS-MODESTUS AND BALANUS-PERFORATUS CYPRIDS TO BACTERIAL FILMS GROWN UNDER DIFFERENT SHEAR REGIMES

The tenacity of cypris larvae of the barnacles (Crustacea: Cirripedia) Balanus perforatus (Bruguiere) and Elminius modestus Darwin was measured on multispecies biofilms developed under contrasting shear regimes. For both species, relatively thin, dense biofilms associated with high shear (83 s-1) afforded increased tenacity over relatively thick, less dense films associated with low shear (15 s-1). Although both species showed reduced tenacity on low-shear films compared to high-shear films, E. modestus cyprids attached as strongly to low-shear films as they did to unfilmed surfaces. Balanus perforatus cyprids, however, attached less strongly to low-shear films than to unfilmed surfaces. The results show that B. perforatus and E. modestus may appreciate differences in bacterial communities grown under different shear conditions and highlight the potential for biofilms as one of the many cues to barnacle settlement.