Shell wiping in Calliostoma zizyphinum: the use of pedal mucus as a provendering agent and its contribution to daily energetic requirements

The phenomenon of shell wiping in Calliostoma zizyphinum (L.) was investiga ted with regard to its potential function as a feeding adaptation. It was d etermined that C, zizyphinum will, on average, wipe the surface of its shel l with its foot twice every 24 h, in the process consuming any matter that has adhered to the pedal mucus present on the surface of its shell. Examina tion of the importance of shell wiping to C. zizyphinum, both as a mechanis m to reduce shell fouling and as a source of nutrition, revealed that the p revention of shell wiping resulted in a reduction in shell growth by a fact or of 0.67 and an increase in shell fouling by a factor of 9. Measurement o f the metabolic rate of C. zizyphinum ascertained that an average sized adu lt had a metabolic requirement of similar to 117 J 24 h(-1) Examination of the ability of the pedal mucus produced by C. zizyphinum to act as a proven dering agent showed that the pedal mucus produced by C. zizyphinum could in crease the entrapment of particulate matter by a factor of 8, and increase the chlorophyll a content of a substratum by a factor of 3. Calculation of the potential contribution of the matter trapped by pedal mucus, which is i ngested through shell wiping, to the daily energetic requirements of C, ziz yphinum revealed that shell wiping can contribute to approximately one-fift h of the daily energetic requirement of C. zizyphinum. Shell. wiping theref ore has an important role for both feeding and antifouling in C, zizyphinum .