Grades 3–5 · Organisms
How do ants leave a trail that others can follow?
A line of ants may seem to know exactly where to walk. In many ant species, part of the explanation is a chemical trail. A worker that finds food can leave small amounts of scent as it returns toward the nest. These chemicals are called trail pheromones.
In the diagramSome ants mark a useful route with scentNestmates detect trail chemicals with their antennaeNestFoodSuccessful returning ants add scentReturn from food toward nestThe scent marks a path; it does not point toward food.Other cues and ant behavior also affect which route is followed.
Other workers detect the chemicals with their antennae. The scent can help them stay near a route that connects the nest with a feeding place. It is not a tiny arrow pointing toward food. Ants also use their own movements, experience and other information when finding their way.
Workers that successfully return from food may add more scent. Repeated trips can renew the trail while it remains useful. A route therefore changes through the actions of many ants, without one ant drawing a map for the whole colony.
When the food runs out or workers stop renewing a trail, its scent can fade. Some chemicals evaporate, and the route may become harder to follow. Different ants use different systems, so this is one common kind of communication rather than a rule for every ant.
About this explanation
Starting knowledge: Recognize insects, antennae and a nest.
Sources
- Penn State · Narendra and colleagues — Foraging ants trade off further for faster: Use of natural bridges and trunk trail permanency in carpenter ants
- Oregon State University Extension — Integrated pest management for ants in schools