1965] 
Wilson — Trail Sharing 
7 
by the Camponotns. Thus the Camponotus workers appear to respond 
to two odor trails, while the host Azteca respond only to one. 
Acknowledgements 
This study was supported by a grant from the National Science 
Foundation. The figure was prepared by Mrs. H. C. Lyman. 
ABSTRACT 
Trail sharing is a rare event in ants. Of two previously described 
cases, one is interpreted as part of a relationship that is either mutu- 
alistic or weakly parasitic, probably the former, and the other as part 
of a weakly parasitic relationship. 
A third, new case has been discovered which appears to be com- 
mensalistic. On Trinidad, West Indies, workers of the rather scarce 
formicine Camponotus beebei utilize the arboreal odor trails of the 
abundant dolichoderine, Azteca chartifex. The Camponotus “borrow” 
the latter’s trails during the day, when Azteca foraging is at a low 
ebb. The Camponotus workers are treated hostilely by the Azteca 
workers but are too swift and agile to be caught; their presence does 
not disturb the Azteca seriously. On a single occasion Camponotus 
workers were observed to lay their own private recruitment odor 
trail on top of the Azteca trails. The Camponotus trail lasted for 
about fifteen minutes and had no visible effect on the Azteca . 
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