ABSTRACT
Successful camouflage requires an animal to be integrated into the environment. When an individual grows, the camouflage is usually modified to maintain the integrated state. How does the animal maintain the whole body-camouflage system as an individual? We studied the cap making behavior of the sponge crab, Lauridromia dehaani that can carry an artificial sponge as a cap. We obtained the behavioral data, including repeated samples, from the same individual crab. Multilevel or hierarchical models are often used to deal with the clustered data. However, the evaluation of the appropriateness of the hierarchical model is a challenge in statistical modeling. This is because it is a statistically non-regular model. Here, we for the first time applied marginal-level WAIC (Widely Applicable Information Criterion) to the behavioral data and found that the hierarchical models remarkably outperformed non-hierarchical ones in decision making of material size and cap making by the crab. Our new modeling approach successfully detected the integrated ‘individuality’ revealed as probabilistic distribution structures in the real world behavioral data.
Footnotes
minor revision