Quantifying the exploratory behaviour of Amphibalanus amphitrite cyprids

Abstract

The behavioural response of cypris larvae from A. amphitrite (=Balanus amphitrite) exploring three model glass surfaces is quantified by close-range microscopy. Step length and step duration measurements reveal a response to both surface properties and flow. Without flow, 2-day-old cyprids took larger steps with shorter step duration on hydrophilic glass surfaces (bare and NH₂-treated) vs hydrophobic glass (CH₃-treated). These parameters suggest a more detailed, local inspection of hydrophobic surfaces and a more extensive exploration for hydrophilic surfaces. Cyprids under flow took longer steps and exhibited shorter probing times on hydrophobic glass. On hydrophilic glass, cyprids increased their step duration under flow. This active response is attributed to drag and lift forces challenging the cyprids' temporary anchoring to the substratum. Seven-day-old cyprids showed almost no discrimination between the model surfaces. Microscopic-scale observation of cyprid exploration is expected to provide new insights into interactions between cyprids and surfaces.

Keywords:

• cypris larva
• cyprid behaviour
• antifouling surface
• behavioural assay

Acknowledgements

This work was supported by the Science and Engineering Research Council (SERC), A*STAR, Singapore. The authors thank Dr Serena Lay Ming Teo and Ms Serina Siew Chen Lee for providing a steady supply of cyprids. The authors are also grateful to the reviewers for their valuable comments and suggestions.