NESTING ASSOCIATIONS OF WASPS AND ANTS 
ON LOWLAND PERUVIAN ANT-PLANTS 
By Edward Allen Herre, 12 Donald M. Windsor, 1 
and Robin B. Foster 1 
Introduction 
Neotropical vespid wasps are known to form nesting associations 
with other species of wasps and ants. For instance, Mischocyttarus 
immarginatus nests primarily in association with the larger and 
more aggressive colonies of certain polybiine wasps in the savannas 
of northwestern Costa Rica (Windsor 1972, 1973). Examples of 
wasp species which form interspecific nesting associations with ants 
include Polybia rejecta and Synoeca chalybea, whose nests are usu- 
ally associated with carton building Azteca spp. ant colonies 
throughout the neotropics (Vesey-Fitzgerald 1938, Richards 1945, 
DMW, RBF, EAH personal observations). 
Often the ants with which wasps nest are involved in more or less 
specific associations with host ant-plants. In addition to Azteca 
spp., Polybia rejecta nests can be found in ant acacias which support 
healthy colonies of Pseudomyrmex ferruginea (DMW, RBF per- 
sonal observations). Zikan (1949) has reported that several Mischo- 
cyttarus species nest on the ant plant Cordia nodosa (Boraginaceae) 
inhabited by Azteca spp. and an unidentified species of myrmecace- 
ous Melastomataceae. Richards (1945) reported collecting at least 
one nest of M. metoecus and M. decimus from C. nodosa in 
Guyana. 
Why do these nesting associations exist? Windsor (1972, 1973) 
demonstrated that Mischocyttarus immarginatus nests associated 
with nests of other, more aggressive wasps species survive longer 
and produce more brood. It appears that such nests suffer less dam- 
age from birds which destroy nests and rob brood. Richards (1951) 
suggested that nesting with ants such as Azteca may be one of 
relatively few possible defenses available to tropical wasps against 
'Smithsonian Tropical Research Institute, Box 2072, Balboa, Republic of Panama 
department of Biology, University of Iowa, Iowa City, Iowa 52242, U.S.A. 
Manuscript received by the editor March 20, 1986 
321 
