1986] Heere, Windsor, and Foster — Wasps and ants 323 
upper slopes and hilltops, primarily in gaps formed by treefalls. The 
population is polymorphic for a bright red-purple color on the 
undersides of the leaves. The petioles have a large, bilobed, hollow 
expansion (formicarium) with a pair of openings onto the under- 
sides of the leaf blade (see figure 1). Maieta poeppigii, in 
contrast, is an arching shrub less than 1 m. tall most common on 
brown sand soils, primarily on lower slopes and streambanks. The 
formicarium of Maieta consists of a pair of raised, hollow chambers 
on either side of the midrib at the base of the leafblade. 
Although we found colonies of at least eight different species of 
ants inhabiting different Tococa guianensis individuals (eg. Azteca 
spp., Dolichoderus spp., Pseudomyrmex spp., Crematogaster spp., 
and Gnamtogenys spp.), the majority of the plants we encountered 
were occupied by colonies of the ant Allomerus octoarticulatus 
(Allomerus) (18 of 34 plants in one census). Allomerus builds a 
characteristic carton tunnel of cemented debris with small holes 
regularly spaced over the surface (see figure 1). These structures 
envelope most of the stems, connect the formicaria, and extend 
down the main stem to within 20 cm. of the ground. Most ant 
activity is confined to the formicaria and these tunnels. Unlike 
other species of ants which we observed on these plants, we did not 
observe Allomerus foraging off the host plant either on any casually 
observed plants or on focal plants watched at hourly intervals 
between 5 am. and 1 am. In addition, the presence of coccids and 
structures which may have been food bodies or feeding glands for 
the ants (see Roth, 1970) led us to believe that Allomerus derives all 
its nutrition either directly or indirectly from the host T. guianensis, 
much as Pseudomyrmex satanica is supported by farming coccids 
within the hollow outer twigs of Triplaris cumminghami (DMW, 
personal observation in Costa Rica). Allomerus aggressively recruits 
onto leaf surfaces when a plant is disturbed. However, the ants do 
not harm wasp broods although they will swarm all over the wasp 
nest. 
Maieta poeppigii plants were overwhelmingly occupied by Phei- 
dole spp. ants (94 of 101 plants). Unlike Allomerus, the Pheidole 
spp. do not build tunnels, although they do characteristically store 
debris in one of the two paired chambers at the base of each leaf. 
The Pheidole spp. ants are not particularly aggressive. Occasional 
minor workers can be found outside the formicaria. Major workers 
and minor workers emerge from the formicaria in large numbers 
