NOTES ON THE BIOLOGY OF 
POLISTES CARNIFEX (HYMENOPTERA, VESPIDAE) 
IN COSTA RICA AND COLOMBIA* 
By Mary L. Corn 
The Biological Laboratories, Harvard University 
Cambridge, Massachusetts 02138 
According to Bequaert (1936), Polistes carnifex (Fabricius) is 
the largest representative of the genus in the Neotropics. Its distribu- 
tion extends from northern Argentina to Mexico. Little is known 
of its biology or behavior. Bertoni (1911) described a nest from 
Paraguay; Bequaert (1936) named new color varieties; Reid (1942) 
studied the developmental stages; and Weyrauch (1942) described 
a nest of P. carnifex var. boliviensis in Peru. These authors noted 
that carnifex builds a pendant, horizontal, open-faced nest with a 
single, central pedicel. The pedicel is covered with a tough, dark, 
gelatin-like material. 
My observations were conducted in 2 areas. Site A was near 
Palo Verde, Guanacaste Province, Costa Rica. Six nests were taken 
there in July, 1971, in the rainy season. Site B was in the vicinity 
of Cali, Colombia, where I observed an individual nest for over 
30 hours over a 2 week period at the close of the dry season in Jan- 
uary, 1972. 
At Site A the six nests were among dozens of carnifex nests in 
various low, shrubby, thorn bearing trees, some of which were 
legumes, though several species were represented. The trees grew 
along the edge of a large seasonal swamp. Most of the nests were 
associated with (that is, in the same tree, less than 1 m from) large 
nests of a polybiine, probably Polybia sp. Rarely, a third wasp, Mis- 
chocyttarus sp. nested in the same cluster. Windsor (1972) has 
found an association of Polybia and Mischocyttarus in the same 
province, but carnifex was rarely found in it, though the other two 
species are possibly the same. At site A, the nests of all 3 species 
sometimes occurred within 1 m of each other. Since many trees con- 
tained no nests of carnifex at all, the distribution seemed non-ran- 
dom. The association of carnifex with other species of social wasps 
has not been reported elsewhere. 
P. carnifex was much less aggressive than its size might suggest. 
Entire nests were captured safely at night. Only two adults were 
* Manuscript received by the editor May 8, 1972. 
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