1=) 



H 



o 

 o 



w 

 ft 



> 



H 

 O 



[9 



CO 



J20 



100 



80 



60 



40 



20 



FISH RANK 



Figure 3. --Chases given by each rank to each rank below it. Data from all seven 

 groups are summed. Each line represents the chases given by a particular rank 

 to all ranks below it; e.g., rank 1 chased rank 2 a total of 96 times. The 

 asterisks denote significant differences (p < 0.05) between adjacent points; 

 e.g., rank 1 chased rank 2 significantly more than it did rank 3. 



(d) ranks 2, 3, and 4 receive most chases and ranks 1, 5, and 6, the least. 



It is clear that in the bicolor damselfish, size plays an important role 

 in intraspeci f ic aggression. As in many other species, dominance relations are 

 strongly correlated with body size (beetles, Beebe, 1947; lobsters, Fielder, 

 1965; voles and deermice, Grant, 1970). Aggression is most intense between 

 individuals of similar size and least intense between individuals most dissimilar 

 in size (Noble, 1939; Collias, 1944; Miller, 1964; Coates, 1977). 



The importance of size in the dominance relations of damselfish may result 

 from size-dependent competition for certain resources. Individuals of different 



134 



