Centimetre-scale Landscapes to Assess the Motion Behaviour and Cognition of Gastropods and Bivalves.

Most ectotherms typically navigate topographically complex landscapes to find food and sexual partners while avoiding predation. However, it is still unclear how chemical, visual and contact cues interact and drive the behavioural complexity observed in these organisms. This contribution illustrates how behavioural ecologists could take advantage of the unique modularity, chemical inertness, scalability, simplicity and affordability of LEGO® bricks and parts to create hypothesis-driven landscapes of various levels of complexity to unambiguously assess the behavioural responses of gastropods and bivalves and their ability to make choices in response to a range of chemical, visual and contact cues. The present work is based on terrestrial, freshwater and intertidal gastropods and two species of marine bivalves. I first demonstrate the chemical inertness of LEGO® bricks and parts towards gastropods and mussels. Then, purpose-built LEGO®-based experimental arenas are used to illustrate how they can be applied to address key issues and hypotheses related to the way gastropods and mussels perceive and react to a range of relevant chemical, visual and contact cues. In summary, this work provides a conceptual and technical framework to resolve to what extent motion behaviour is driven by a synergistic combination of chemotaxic, geotaxic, rheotaxic and thigmotaxic processes. This article is part of the theme issue 'Life in natural microcosms'.