POLYMORPHISM IN STELOPOLYBIA AREATA 
(HYMENOPTERA, VESPIDAE) 
By Robert L. Jeanne 11 and Robert Fagen 2 
Polymorphism in the social Hymenoptera has been defined as the 
occurrence within a single colony of two or more distinct morpho- 
logical forms, or castes, belonging to the same sex (Wilson 1953). 
Wilson (1953) has pointed out that polymorphism arises out of the 
occurrence of allometry (differential rates of growth of two parts of 
the body) over a sufficient range of intranidal size variation to pro- 
duce morphologically distinct forms at the extremes of this size range. 
The underlying size variation is due in most cases to differences in 
larval nutrition (Michener 1961; Wilson 1971). Polymorphism is 
the morphological adaptation to the functional division of tasks among 
the members of a colony (Wilson 1953). The most fundamental 
polymorphism is the separation of the reproductive caste (queens) 
from the non-reproductive caste (workers). This is followed, most 
notably in the ants, by the evolution of more or less distinct castes 
among the workers. 
Among the wasps polymorphism appears to be limited to the queen- 
worker dimorphism, where it is most pronounced in the Vespinae 
(Wilson 1971). Among many of the Polistinae there is no detectable 
difference, either in size or in morphology, between functional queens 
and workers (Richards and Richards 1951). The present paper 
reports the occurrence of complete queen-worker dimorphism in 
colonies of the polistine species Stelopolybia areata (Say) from 
Mexico. 
Materials and Methods 
Stelopolybia areata ranges from Mexico south to northern South 
America (Ducke 1910). The four colonies available for the present 
study were collected near San Andres Tuxtla in southern Veracruz, 
Mexico, in January and February 1973. During these months the 
nests are occupied by adult females only. No brood or males are 
present. Population size and composition for each colony are given 
department of Biology, Boston University, Boston, Massachusetts 02215. 
Aiken Computation Laboratory, Harvard University, Cambridge, Massa- 
chusetts 02138. 
Manuscript received by the editor February 20, 1974. 
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