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Psyche 
[Vol. 91 
Summary 
Exterior workers in laboratory colonies of the southern harvester 
ant, Pogonomyrmex haclius, were marked while performing one of 
the following: 1 . midden work, 2. patrolling, 3. nest maintenance, 4. 
convening, or 5. foraging. These activities were consistently per- 
formed by marked ants for at least 35 days. The results indicate that 
the five activities are performed by four distinct groups of ants; it 
appears that midden work and patrolling are done by the same ants. 
Three months after marking, conveners had become foragers, and 
nest maintenance workers had become patrollers. Younger, callow 
ants were most often observed convening. Midden workers and 
patrollers died sooner than other marked ants. These results show 
how role may depend on worker age. In this species the minor caste is 
continuously polymorphic, but no evidence for size polyethism 
within the minor caste was found. 
Acknowledgements 
I thank T. Meagher, M. Rausher, and especially R. Lewontin for 
advice on analysis of the data; S. Porter, T. Seeley, A. Lenoir, and P. 
Klopfer for comments on the manuscript; and J. Gregg and R. 
Palmer for their help throughout the project. 
R I I I RI NC I S 
Bhaktar. A. W. and W. Whitcomb. 1970. Artificial diet for rearing various 
species of ants. Fla. Entomol. 53(4): 229 232. 
Ghntry. J. B. 1974. Response to predation by colonies of the Florida harvester 
ant. Pogonomyrmex badius. Ecol. 55: 1328 1338. 
Gordon, D. M . 1983a. Dependence of necrophoric response to oleic acid on social 
context in the harvester ant. Pogonomyrmex badius. J. Chem. Ecol. 9(1): 
105 111. 
1983b. Relation of recruitment rate and activity rhythms in the harvester 
ant, Pogonomyrmex harbatus. J. Kans. Ent. Soc. 56(3): 277-285. 
1984a. Species-specific patterns in the social behavior of harvester ant 
colonies (Pogonomyrmex). lnsectes Sociaux: 31(1): 74-86. 
1984b. The harvester ant (Pogonomyrmex badius) midden: refuse or 
boundary? Ecol. Ent., 9: 403 412. 
HOi. i. dohi.hr, B. 1976. Recruitment behavior, home range orientation, and terri- 
toriality in harvester ants, Pogonomyrmex. Behav. Ecol. Sociobiol. 1: 3 44. 
Lknoir, A. and H. Ataya. 1983. Polythism et repartition des niveaux d’activite 
che/ la fourmi Lasius niger L. J. Comp. Ethol.: in press. 
