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major physical castes. For instance, in Figure 1 examine the minors’ 
behaviors F, G, and E, and the series H through N. The relative 
performance measures for tasks F and G are highest for age class II, 
yet age classes II and I have similarly high RPM for task E. Or, in 
the second case, for all the tasks H through N, age class III shows 
very high RPM, but the task/age class association is not exclusive. 
For K, M, and N at least, other, but not necessarily adjacent age 
classes, show similarly high RPM. 
Discussion 
P. hortensis exhibits both physical and age castes, and the latter 
show continuous rather than discretized polyethism. We will com- 
pare these results with results from other species, and consider some 
of their general implications for the study of age polyethism. 
1. Repertory size and numerical considerations. 
Both repertory size and the proportion of rarely occurring behav- 
iors in P. hortensis are in the same range as those of other species. 
Numbers of behaviors in repertories judged complete by Fagen and 
Goldman analysis are: 27 for workers of monomorphic Leptothorax 
species (Wilson and Fagen 1974) and for minor workers of 
Orectognathus versicolor (Carlin 1982), and 28 each for minor 
Pheidole dentaia (Wilson 1976a), Formica perpilosa (Brandao 
1979), and Camponotus sericeiventris (Busher 1982). Extremes may 
be represented by minor repertories of Solenopsis geminata, S. 
invicta, and Zacryptocerus varians: 17, 20, and 38, respectively 
(Wilson, 1976b, 1978). Repertories for majors range from two 
{Solenopsis geminata, Wilson 1978) to 24 {Orectognathus versi- 
color, Carlin 1982); for the dimorphic Z. varians and P. dentata, major 
repertories are 1 1 and nine (Wilson 1976a and b). Total repertories 
for all these species range from 20 to 40 behaviors. 
Given the similarity in repertory size for minor workers of both P. 
hortensis and P. dentata, it may seem odd that in P. hortensis 
considerably fewer behaviors ( 1 3 vs 23) are performed with age bias. 
The difference results from the respective criteria used to reject 
rarely occurring behaviors from analysis. Because he does not make 
statistical comparisons, Wilson rejects only 2 of 28 behaviors on 
grounds of insufficient data. However, when the cut-off criterion 
