1965] 
Wilson — Trail Sharing 
3 
maintains flourishing populations in localities where virtually every 
colony lives in parabiosis with Crematogaster. 
While the Neotropical parabionts are doubtfully mutualistic, the 
relationship of the European Camponotus lateralis (Olivier) and 
Crematogaster scutellaris (Olivier) can be classified as weakly 
parasitic. Goetsch (1953) and Kaudewitz (1955) have described 
instances in which Camponotus workers followed the Crematogaster 
trails in large numbers to the Crematogaster feeding grounds and 
exploited the same food resources during the same time of day. The 
Crematogaster were hostile to the Camponotus, which assumed a 
crouching, conciliatory “Wartestellung” on meeting the host workers. 
Unlike the Neotropical parabionts, the two species nest separately. 
Moreover, the relationship is not obligatory on the Camponotus 
lateralis , since the colonies of that species are often found far removed 
from Crematogaster colonies. 
I will now describe a third example of trail sharing which I 
recently discovered between the dolichoderine Azteca chartifex Forel 
and formicine Camponotus heehei Wheeler. This case is of additional 
interest in that it seems to illustrate a close approach to the third or 
neutral class of symbiosis, namely commensalism. 
AZTECA CHARTIFEX AND CAMPONOTUS BEEBEI 
During a trip to Trinidad, West Indies, in 1961, my attention was 
drawn to Camponotus heehei, a formicine ant previously known from 
only several specimens collected in Trinidad and British Guiana. On 
each of three occasions on which the species was encountered, twice at 
Spring Hill, Arima Valley, and once near Cumuto Village on the 
Aripo Savanna, workers were found running over tree trunks along 
the odor trails of the much more abundant and aggressive dolichode- 
rine Azteca chartifex. The Camponotus were never found away 
from the Azteca trails. Extended observations at Spring Hill revealed 
that the Camponotus always followed the Azteca trails for long 
distances with fidelity equal to that maintained by the Azteca them- 
selves. That this was true trail symbiosis was further evidenced by 
the fact that no other alien species remotely approximated such 
behavior. Workers of several other arboreal species occasionally 
blundered into the same Azteca files but ran abruptly away without 
tracing the main route of the files. 
One of the Spring Hill Camponotus nests was located. It was in a 
dead, hard branch of a mango tree that had fallen and lodged in the 
crown of a three-meter-tall grapefruit tree in a citrus plantation. The 
Camponotus workers were seen to emerge from their nest holes, run 
