Examination of Agonistic Behavior By Character Analysis Ii. Hermit Crabs

Abstract

Abstract 1. The communications systems of two species of hermit crab were analysed by character analysis. It was found that rough estimates of the amount of information transmitted by displays during an agonistic interaction could be obtained from just 100 fights. However, the values obtained for amount of information transferred tended to be distinctly higher than the values obtained from analysis of 500 fight samples. 2. Unexpected dips in the rate of information transfer seen in analyses of variable length fight samples were largely eliminated by analysing fights of defined length. 3. In all analyses, the amount of information transmitted from crab to crab was lower at the beginning of fights, rose to rather high levels (40-50% uncertainty reduction) in the middle of fights, and at the end of fights, the absolute values decreased while the relative levels of uncertainty reduction increased. 4. From analysis of fights categorized by whether the initiator or responding crab won the fight, it appears that the eventual winners of fights alter their behavior more relative to the behavior patterns shown by the eventual loser than vice versa. This was true for all phases of interactions.