Information gathering and communication during agonistic encounters: A case study of hermit crabs

摘要: Summary 1. Game theoretical models of animal contests assume that animals attempt to maximize individual fitness during with nonrelatives. The asymmetric war attrition takes into account the probability ratio cost benefit for each opponent will be different, but information contestant has about its relative ratio, in comparison opponent, is unlikely perfect. sequential assessment model suggests accuracy this increases performance agonistic activity question. Recent models, however, such as energetic attrition, aggressive signals are performed repeatedly because they accumulate give a signal stamina. 2. Hermit crabs interact pairs apparently encounters over ownership gastropod shells. key these interactions “shell rapping,” where attacker brings shell rapidly and contact defender series bouts. At end an encounter may evict from permanently occupy, new, empty shell. evicted then free occupy discarded by said have “exchanged shells.” Under certain circumstances both interactions. 3. This possibility mutual gain exchanges lead hypothesis negotiate shells negotiation function rapping provide nonrapping crab attacker. would able make decision whether release own on basis change quality entail. aggression model, it expected any transferred concerns either fighting ability attackers, their motivation continue, or combination two factors. In addition, might incur some direct detrimental effect defenders. 4. selection process nonagonistic situations been used gathering motivational change. A threshold investigation relates causal factors, currently occupied potential new shell, decisions available crab: continue investigating enter reject allows various trajectories calculated, which relate time likely crab, different scenarios defined crab's original under investigation. was tested probing state (1) preventing adequate measuring persistence times (2) using novel stimulus startle taken return investigatory behavior. Experiments conducted techniques confirmed use sources predicted model. 5. Motivational vary attackers fights. An indication provided duration up, majority fights eviction defender, hence there too few data test way. technique thus probe It found response related gain, those greater improvement showing shortest durations. Furthermore, were eventually victorious shown higher early escalated phase fight than did not opponent. Surprisingly, appear size difference between crabs. 6. determinants outcome power impact raps, pauses bouts rapping, mean number raps bout, powerful vigorous being more Differences vigor also associated Vigor varies course fight: at start de-escalated, successful increase rate prior evicting whereas up decrease before doing so. only game signaling contest attrition. According repeated stamina receivers. That mediated fatigue staging had preexposed hypoxic water analysis lactic acid concentration hemolymph, following We conclude hermit represent useful involve communication participants. First, value resource question can easily manipulated. Second, unlike other systems, roles fixed throughout rules signalers receivers examined separately.