1988] 
Peeters & Crozier — cast and reproduction 
287 
use “queen” simply to describe individuals which are mated and 
fertile. This confused practice obscures the fact that morphological 
castes do not exist in many eusocial hymenopterans. Thus, in 
primitively-eusocial species, reproductive division of labour occurs 
among morphologically-undifferentiated female adults. In contrast, 
in highly-eusocial species, female adults have one of two different 
phenotypes, and normally only members of the queen caste repro- 
duce. However, in several ponerine ants, the queen caste has been 
lost, and some of the workers mate and lay eggs. The latter have 
sometimes been called “queens”, which conceals their developmen- 
tal history. 
We advocate that “caste”, “queen” and “worker” be used only in a 
strict morphological sense (including both internal and external 
characters), with an additional mention of role when this does not 
correspond with caste membership. 
Acknowledgments 
We are grateful to B. Bennett, W. L. Brown, Jr., A. Buschinger, 
R. Crewe, M. Crosland, M. Elgar, M. Schwarz, M. J. West- 
Eberhard, D. Wheeler and E. O. Wilson for their comments and 
criticisms of various drafts of this manuscript, although not all of 
them agree with our views. We thank the Australian Research Grants 
Scheme for support to R. H. Crozier. 
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