328 
Psyche 
[Vol. 93 
Windsor 1972). More passes are needed and the return in food per 
time and effort is less. Further, a subdivided nest is less vulnerable 
to being entirely wiped out by nest parasites which can move from 
cell to cell (eg. tineid moth larvae described by Jeanne 1979). 
There appears to be no obvious benefit that the ants derive from 
the presence of the timid Mischocyttarus wasps. Why do the ants 
tolerate the presence of these wasps? A review of the ant species with 
which various vespid wasps are reported to form nesting associa- 
tions shows that with the exception of some Azteca species, the ants 
all appear to be nutritionally supported by their host plants. Appar- 
ently the ants either cannot eat the wasp brood or do not recognize 
the wasp brood as a potential meal. Further, in the case of some 
ant-wasp associations such as that between Azteca spp. and Polybia 
rejecta, the wasps have been reported to benefit the associated ant 
colony by discouraging anteaters (R. Silberglied, personal commun- 
ication). The Tococa guianensis plants on which the aggressive Poly- 
bia and Polistes wasps nested were difficult to approach without 
being stung. It is likely that the presence of these wasps reduces 
damage to the host plant and, consequently, the ant colony caused 
by mammals. Therefore, the Mischocyttarus wasps, while not being 
a detriment to the ants, may simply be taking good advantage of a 
tolerance that the ants have developed to more beneficial species of 
symbiotic wasps. 
Acknowledgments 
We wish to thank Don Francisco Pizarro for generous hospitality 
and essential logistic help during our various visits to Casaria 
Mishana, Dr. William Brown for kindly indentifying all ant species 
mentioned, Dr. J. J. Wurdack for identifying the Tococa and 
Maieta species, and, especially, the late O. W. Richards for identify- 
ing the wasp species and encouraging this work with his enthusiasm 
and expertise. D. E. Wheeler, D. M. Feener, L. Johnson and the 
Iowa Writing Seminar Group provided helpful comments on the 
manuscript. This work was supported by The Smithsonian Tropical 
Research Institute (DMW, EAH), The Harris Foundation (EAH), 
and The University of Iowa’s Teaching and Research Fellowship 
Program (EAH). 
