- Pheromones: These are chemical signals released into the environment that can influence the behavior of other individuals of the same species. Pheromones can be used to mark territory, attract mates, warn of danger, and more.
- Allomones: These are chemicals that benefit the sender but harm or deter the receiver. For example, many insects release allomones to deter predators.
- Kairomones: These are chemicals that benefit the receiver but harm or deter the sender. For example, many plants release kairomones to attract pollinators.
- Synomones: These are chemicals that benefit both the sender and the receiver. For example, many flowers release synomones to attract pollinators.