BehaviourLow risk
Why Are Ants Following a Line?
Quick answer
Ants walk in lines because they are following a chemical scent trail called a pheromone trail. When a worker finds food or water, it marks the route back to the nest. Other workers follow and reinforce the trail, creating the familiar line. The trail fades when the food runs out.
Why this happens
Ants communicate largely through chemicals. Trail pheromones are laid by workers as they walk, and the strength of the trail reflects how rewarding the resource is.
Because the trail links the food to the nest, following the line backwards is one of the best ways to find where ants are entering or nesting.
What you may be seeing
- A steady line of ants moving in both directions.
- Ants bunching at a food source at one end and disappearing into a gap at the other.
What you can do
- Follow the line to find the entry point.
- Wipe the trail with detergent or vinegar solution to remove the scent.
- Remove the food source and seal the entry.
- If using baits, place them beside the trail so foragers carry them back to the colony.
When professional help may be needed
Trails that keep returning to the same place, especially from inside walls, may indicate a nest within the structure.
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Local information
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Sources & further reading
- Australian Museum — insects and spiders — Australian Museum
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