Fighting strategies in crayfish Orconectes rusticus (Decapoda, Cambaridae)differ with hunger state and the presence of food cues

Crayfish, bearing dangerous weapons in the form of chelae, resolve intraspe cific conflicts using stereotyped behaviors and structured, escalated encou nters. According to predictions of game theory models, any decision to reso rt to unrestrained combat without prior careful behavioral assessment of th e opponent's fighting abilities carries great risks. The present study exam ines the significance of internal hunger states and the presence of chemica l food cues in this decision process using a 2 x 2 factorial design. Hungry crayfish escalated more rapidly, and thus took greater risks, during agoni stic encounters, while the presence of a food source reduced the rate at wh ich fights increased in intensity. However, there were no significant diffe rences in fighting behavior as a result of the interaction between these tw o variables. We then address the complex tradeoffs that individuals face in fighting with respect to increased risks of injury, appetitive states, and opportunities for resource access.