Figure 5. Effect of phentolamine on agonistic bouts.

A, Winning rates of subordinate large crayfish injected with saline, phentolamine of 10 µM or 25 µM and 20 µM mianserin in pairing with naive small crayfish are plotted. Physiological saline, phentolamine or mianserin was injected into subordinate animals immediately after establishment of dominant-subordinate formation, and then paired with naive small crayfish after overnight isolation. B, The time during which the dominant-subordinate relationship was determined in both pairings between saline-injected subordinate large crayfish and untreated naive small crayfish and pairings between 25 µM phentolamine-injected subordinate large crayfish and untreated naive small crayfish. Box plots show median (solid black line), interquartile range (box length), and minimum and maximum values (error bars). Asterisk indicates that the time for social rank formation was different statistically (Log-rank test, *p<0.05). C, The number of fights of pairings during the first 30 min of agonistic bouts. D, The average duration of individual fights of pairings during the first 30 min of agonistic bouts. Asterisk indicates that the duration of responses differed significantly (Mann-Whitney rank sum test, *p<0.05).