AGE POLYETHISM: ITS OCCURRENCE IN THE ANT 
PH El DOLE HORTEN SIS. 
AND SOME GENERAL CONSIDERATIONS. 
Bv Prassede Calabi', James F. A. Traniello' % and Michael H. 
Werner' - 
InTRODUC TION 
A main theme of eusociality is division of labor (Wilson 1971, 
1975), which can be based on physiological differences (as in the 
case of the reproductive queen and sterile workers), morphological 
(size) differences among workers, or age differences within a physi- 
cal class. In social insects both age and physical classes can comprise 
castes, that is, groups of individuals which perform specialized labor 
for sustained periods of time (physical castes: Oster and Wilson, 
1978; Wilson, 1980a, b; Herbers, 1980; age castes: Oster and Wilson, 
1978; Porter and Jorgenson, 1981; Mirenda and Vinson, 1981; See- 
ley, 1982). We constructed an ethogram for the Indo-Australian ant 
Pheiclole hortensis. and tested the general hypothesis of division of 
labor in the worker caste by seeking to answer these questions: 
1. Is there division of labor between physical castes? 
2. Is there division of labor among age classes within a physical 
caste? 
3. And if there is age polyethism, is it continuous or discrete? (See 
Wilson 1976a.) 
We will consider and discuss each question separately, and then 
compare our results with those from other studies on social insects. 
In particular we will contrast age polyethism in Pheiclole horteusis 
with that of a New World Pheiclole species, P. clentata. 
Materials and Methods 
Data Collec tion 
Three colonies of Pheiclole hortensis were collected in July 1979 
from virgin rainforest at Gilmale, Sri Lanka by Anula Jayasuriya. 
'Department of Biology, Boston University. Boston. MA 02215 
-Museum of Comparative Zoology Laboratories, Harvard University, Cambridge. 
MA 02138 
Manuscript received hy the editor August H. I9S3 
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