AGONISTIC INTERACTIONS IN MALE FORM-II CAMBARUS-ROBUSTUS GIRARD, 1852CRAYFISH (DECAPODA, CAMBARIDAE) AND A COMPARISON BETWEEN MALE FORM-I AND FORM-II INTRA-FORM CONTESTS

An analysis of intra-form agonistic contests between size-matched mate Form II (non-breeding form) Cambarus robustus Girard, 1852 crayfish r evealed that, the winners and losers of these contests differed in the numbers and types of initiation behaviours used. The (eventual) winne rs, which initiated significantly more fights overall, used mostly the aggressive Claws Raised and Lunge initiation behaviours, whereas the (eventual) losers, which also initialed most of the very first fights of the overall agonistic contests, used mostly the tentative Ambivalen t Contact behaviour. Thus, initiation behaviours can be used as good p redictors of status for males of this species. The Lunge behaviour is a strong indicator of the eventual dominant status of male crayfish, d uring agonistic contests. There was a significant, negative correlatio n between the relative frequency of the Lunge initiation behaviours us ed by the winners and the total time spent fighting. A comparison betw een the male Form II and Form I(breeding form) intra-form contests, in this species, and an analysis of the differences and similarities bet ween these: two types of contests, indicated that male form is an impo rtant variable in the agonistic interactions of cambarid crayfish.