Animals secrete these pheromones to trigger different kinds of behaviour.

Source: https://indianexpress.com/article/technology/science/scientists-sex-perfumes-replace-pesticides-8569187/

Ants obviously can’t talk, so the player has to communicate with the colony using pheromones.

Source: https://gamerant.com/forgotten-msdos-games/

Through pheromones on webs, they can sense that there are black widows nearby, and they can differentiate between a black widow and another type of spider.

Source: https://www.bostonherald.com/2023/03/20/spider-wars-black-widows-are-being-killed-off-by-non-native-brown-widows/