Characterising the Behaviour of the Ctenophore Pleurobrachia pileus in a Laboratory Aquaculture System

Abstract

Neurobiological research focuses on a small number of model organisms, broadening the pool of animals used in research may lead to important insights into the evolution of nervous systems. The ctenophore is emerging as a promising model, but we are currently lacking an understanding into the relationship between behaviour and environment which is in part due to a lack of a standardised long-term laboratory husbandry system. We established a collection and husbandry system for wild caught Pleurobrachia pileus. We examined the behavioural profile of the animals over time in this controlled environment. We could reliably catch them on a seasonal basis, and we could keep the animals alive in our specialised aquarium system for months at a time. P. pileus spends most of the time in an inactive drifting state which is interspersed with periods of one of 5 active behaviours. The most common active behaviours are tentacle resetting and feeding. The longest duration behaviours include swimming up or down. Time of day does not appear to alter their behavioural profile. Gaining a better understanding of the behaviour of these animals has important implications for systems and evolutionary neuroscience.