No Brain? No Problem! Brittle Stars Are Capable of Associative Learning
Julia C. Notar, Madeline C. Go, Sönke Johnsen
Presented at the 2023 Society for Integrative and Comparative Biology Annual Meeting, Austin, TX
Videos from talk
- Video 1 - Phase I, Control (side view)
- Trained animals fed during the Control Period.
- Video 2 - Phase II, Training (side view)
- Trained animals receiving training. They are fed at the very start of the Dark Period.
- Video 3 - Phase III, Training & Testing (above view)
- Trained animals emerging in Dark Period, without food present. They are then fed 15 min into the Dark Period.
Abstract
There has been a recent growth in interest in the processes governing the coordination and control of locomotion in the decentralized nervous systems of echinoderms, yet our understanding of echinoderm behavior and learning remains poor. In this study we tested whether brittle stars (Class Ophiuroidea) were capable of learning to associate two cues: a short period of darkness and the presentation of a food cue. Individually housed Ophiocoma echinata were separated into experimental (trained) and control (untrained) groups. Animals in the experimental group were trained by presenting food during a short period of darkness, while control group animals were fed under regular daytime room lights many hours after the period of darkness. After the training period, the experimental group demonstrated they had learned to associate the two cues by regularly emerging during the dark period even when no food was presented. In comparison, control animals did not spontaneously emerge during the dark period (p = 0.0007). This shows that an ophiuroid species is capable of more advanced neural processing tasks than previously appreciated.
This study is now published in Behavioral Ecology and Sociobiology Notar, JC, Go, M, and Johnsen, S. (2023) Learning without a brain: Classical conditioning in the ophiuroid Ophiocoma echinata. Behavioral Ecology and Sociobiology, 77:126, https://doi.org/10.1007/s00265-023-03402-x Read for free here: https://rdcu.be/duUvx