The temporary adhesion of barnacle cyprids: effects of some differing surface characteristics

Abstract

The tenacity of the barnacle cyprids ofBalanus balanoides(L.) during temporary adhesion to a variety of modified Perspex surfaces was tested using a sensitive microbalance. The Perspex panels were painted on the undersides with five colours of cellulose paint. Control measurements of the magnitude of temporary adhesion to clean slate panels were of the order of 2 × 10 N m. Untreated smooth Perspex panels and panels coated with an adsorbed layer of bovine serum albumen gave low figures of tenacity of the order of 0·8 × 10 N m. Roughening the panels with carborundum or treating with an adsorbed layer of barnacle extract protein resulted in higher tenacity measurements (1·0–1·8 × 10 N M), whereas the highest measurements were obtained when roughened Perspex panels were coated by an adsorbed layer of barnacle extract protein (1·6–2·2 × 10 N M). When the surfaces were made more attractive to barnacle cyprids by roughening or coating in barnacle protein the forces measured on dark coloured panels were higher than on lighter coloured panels. The results of the temporary adhesion measurements were closely paralleled by the numbers of cyprids found exploring the various surfaces during preference settlement experiments.