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[Vol. 92 
reduction of minor worker numbers to below the threshold. Wilson 
suggests that Pheidole majors serve as an “emergency stand-by 
caste” following periods of high minor worker mortality. 
One possibility is that the apparent behavioral flexibility of A. 
notabilis majors could be a result of the small size of Acanthomyr- 
mex colonies. In small colonies it is likely that the number of minor 
workers available at any given time will often drop below some 
minimum necessary to carry out the normal affairs of a colony; as a 
result frequent temporary crises can be expected to occur. For 
example, a single rich food find could divert much of the limited 
population of minors to food harvesting activities, so that for a time 
an insufficient number of minors are available to care for brood; a 
larger colony will probably be able to draw upon a reserve force of 
minor workers to handle such situations. If such labor crises are 
indeed common, it may be most effective to lower the thresholds 
beyond which majors perform the behavioral acts typical of minors, 
so that the threshold is closer to the normal ratio of majors to 
minors than Wilson (1984) found for Pheidole. Perhaps the death of 
about half of the original minor worker population prior to the start 
of my observations on the captive A. notabilis colony had been 
sufficient to elicit an expansion of the major behavioral repertoire. 
If so, further studies may show that under most conditions the 
repertoire of majors is restricted to defense and seed milling. 
Acknowledgements 
I am very grateful to John MacKinnon for assistance in Indonesia 
and Deborah A. Fletcher for field assistance, as well as Peter F. 
Stevens for identifying the seeds, and William L. Brown, Jr. and 
Edward O. Wilson for comments on a draft of the manuscript. 
Literature Cited 
Fagen, R. and R. Goldman 
1977. Behavioral catalogue analysis methods. Anim. Behav. 25:261-274. 
Kugler, C. 
1978. A comparative study of the myrmicine sting apparatus (Hymenoptera: 
Formicidae). Studia Ent. 20:413-548. 
Moffett, M. W. 
in press Revision of the genus Myrmoteras ( Hymenoptera : Formicidae). Bull. 
Mus. Comp. Zool. 
