An odor trail laid more or less continuously by the advance workers of a foraging group: An exploratory trai is a kind of communication and is used regularly by army ants.

A chemical trace laid down by one insect and followed by another: The odorous material of the odor trail is referred to either as the "trail pheromone" or the "trail substance".

An odor trail laid by scout workers: A recruitment trail is used to round up nest mates to a food find, a desirable new nest site, a breach in the nest wall, or some other place where the assistance of many workers is needed.

A substance laid down in the form of a trail by one animal: A trail pheromone is important so that another member of the same species.can follow the path successfully.

The intrusion of one species into the social system of another: An example of trophic parasitism is when a foreign species utilizes the trail system) in order to steal food.