What are pheromones used for?

Pheromones are used by both animals and plants to boost their chances of survival – here are five of the main ways they use them:

1. Raising the alarm
When certain species of insect or plant are under attack, they release alarm pheromones, alerting other members of their species to the danger. All individuals collectively respond to the alarm, either fleeing or mounting a unified defence.

2. Marking territory
Many animals use pheromones to mark the boundaries of their territory – a familiar trait of dogs. Some insects also use pheromones to signpost the location of their eggs, to prevent other females from laying in the same place.

3. Leaving a trail
A pheromone trail is the invisible road that guides ants. As more ants travel along the route, they add their own pheromones. Foraging ants will also leave trails to food but stop as the source is depleted, so the scent dissipates.

4. Recruitment
Bees scour large territories to find nectar, so in order to ensure they return to the hive, workers secrete a pheromone to direct them home. This powerful chemical messenger also attracts lone bees to join the colony as they fly past.

5. Finding a mate
Pheromones can be used to bring individuals together, whether for mating, defence or migration. Females often release pheromones to signal fertility, eg the female silkworm moth can lure a mate from up to 48 kilometres (30 miles) away!