Personality Traits of the Territorial Crustacean Chinese Mitten Crab (Eriocheir sinensis): Behavioral Adaptations to Environmental Cues

Territorial crustaceans exhibit a complex set of personality traits and behavioral characteristics that are critical for their survival, growth, and overall welfare. This study aimed to systematically investigate the interplay between two essential personality traits-boldness and aggression-in Chinese mitten crabs (<i>Eriocheir sinensis</i>), during various developmental stages under conditions of crowding stress and food odor stimuli. Using behavioral assays, we found that adults displayed significantly higher levels of boldness and aggression compared to juveniles. Notably, bold adult crabs demonstrated lower aggression than their shy counterparts, revealing a significant negative correlation between boldness and aggression under crowding stress. Furthermore, juvenile and adult crabs exhibited negative correlations between the stability of their boldness and aggression with individual levels of boldness and aggression, respectively. The study also found that while juvenile boldness did not significantly correlate with body size, larger individuals displayed higher boldness under stress, contrasting with adult crabs, where boldness negatively correlated with body size, although aggression levels were unaffected by size; the stability of adult boldness demonstrated a positive correlation with body size under crowding stress. These findings elucidate the intricate dynamics of personality traits in territorial crustaceans, laying the groundwork for future research into their adaptive behavioral strategies in response to environmental cues like group stress and food odors.