Attachment forces and the role of suction in the sea anemone Metridium farcimen

Abstract

This paper looks at the forces involved in the attachment of M. farcimen to substrate. Many sessile and transitory, aquatic animals rely on the secretion of an adhesive glue for attachment to substrate, like most sea anemones. However, other attachment mechanisms exist. For example, limpets and clingfish rely on suction. The pull off forces of M. farcimen attached to substrate were tested, and then used to calculate tenacity. Two groups were compared. One group was tested with M. farcimen attached to acrylic glass with 1.5mm holes drilled throughout, and the other was tested with M. farcimen attached to acrylic glass without any holes. Tenacity calculations revealed that specimens were more strongly attached to the acrylic glass without holes, suggesting that suction is involved in M. farcimen attachment to substrate. Attachment site selection was also explored. When M. farcimen were given the choice between substrates with holes and substrates without holes, there was no significant difference in the frequency of selection for attachment.