1965] 
Wilson — Trail Sharing 
5 
down the mango branch to the branches of the grapefruit tree, which 
held an Azteca colony, and follow the Azteca trails to the ground. 
The Azteca workers seldom ventured up to the Camponotus nest. 
The Camponotus occupied scattered flat galleries in the mango branch. 
When cut apart the nest yielded 2 winged queens, 16 males, 6 major 
workers, 36 minor workers, and several larvae and pupae in various 
stages of development. The mango tree, from which the Camponotus 
colony fragment had evidently recently fallen, was also occupied by 
Azteca chartifex. In a second locality at Spring Hill, Camponotus 
workers were tracked up into the foliage of a tonka bean tree 
( Dipteryx sp.) beyond a large Azteca nest, but the Camponotus nest 
was not found. Nevertheless, it was evidently separate from the 
Azteca nest. 
Both the Azteca and Camponotus followed the Azteca trails to the 
bases of the nest trees. Presumably both foraged extensively on the 
herbaceous ground vegetation, but their diets were not determined. 
Regardless of the nature of the diets, competition between the two 
species was reduced by the existence of opposite diel schedules. The 
Camponotus foraged apparently exclusively during the day, at the 
time the Azteca files were at their lowest ebb. In the early evening the 
number of Azteca workers on the trails were seen to increase by as 
much as a hundred-fold, but not a single Camponotus worker was 
found through several (hours of searching during this time. 
The Camponotus workers, then, “borrow” the Azteca trails when 
the owners put them to minimal use. The Azteca workers on the 
Spring Hill trails were hostile to the Camponotus workers and 
attacked them on the rare occasions when the latter slowed in their 
running, but the Camponotus were larger and faster and usually 
easily avoided their hosts without causing any visible disturbance. 
The Camponotus were never observed to interfere with the Azteca 
in any other way. 
On the basis of the first observations it could still be legitimately 
asked whether the Camponotus were merely using the same visual 
or tactile “landmarks” on the tree trunks as the Azteca, rather than 
following their odor trails. This possibility was eliminated by the 
following experimental result. A freshly killed insect was pinned to 
the trunk of a tree one meter beneath the trail along which both 
species were running but within the range of occasional Azteca 
scouts. Within ten minutes, two Azteca workers had found the 
insect and laid odor trails from it back to the main trail. In the next 
five minutes over 100 Azteca workers moved back and forth along the 
new trail to the insect. In the same interval three Camponotus 
