FORCE AND DOMINANCE IN THE AGONISTIC BEHAVIOR OF THE FRESH-WATER CRABPOTAMON FLUVIATILE

In decapods, no analysis has ever been conducted of the force exerted by chelae, and the role that strength plays in the establishment of hi erarchies. For this purpose, a device was designed to measure the forc e produced by the major chela in the freshwater crab Potamon fluviatil e, where dominance hierarchy and agonistic behavioral patterns have pr eviously been analyzed. Experiments showed that only in the females is strength the main factor influencing the outcome of contests, In male s chela size more than chela strength is used to settle conflicts, tog ether with other nonphysiognomic characteristics, molding the aggressi ve state of one individual, such as its history, including isolation f rom conspecifics, and possibly hormone concentration and metabolic lev els. (C) 1995 Wiley-Liss, Inc.