Weapon performance and contest assessment strategies of the cavitating snaps in snapping shrimp

Animals compete in contests over limited resources. Contestants forfeit once they ascertain that their opponent has greater resource holding potential (RHP) (mutual assessment) or once they reach a threshold of costs (self assessment). Functional scaling studies of contest behavior performance can inform how assessment signals, offensive capacity, and endurance scale with RHP and thereby elucidate the mechanisms through which each of these assessment types operate. Here, we performed behavioral contest analyses to determine the assessment strategies used in snapping shrimp (Alpheus heterochaelis) contests. Then, we used biomechanical measurements of a common contest behavior to inform how assessment might operate. We were specifically interested in the snapping behavior during which snapping shrimp fire imploding cavitation bubbles – hereafter, “snaps” – at their opponents. We showed that A. heterochaelis use mutual assessment early in contests.  Then, when they fire snaps, they switch ...