Pheromones by definition are chemical molecules released by a living organism to trigger a response or to elicit specific behavioural expressions in organisms of the same species. They are signalling molecules which may be contained in body fluids.
The term pheromone comes from the Greek words pheran which means to transfer and horman which means to excite. Pheromones essentially trigger response in organisms of the same species.
Examples of this abound among insects. Ants and honey bees release alarm pheromones to warn other insects of their own species of impending danger in a particular location. Some species of insects, usually the female, release pheromones to attract mates of opposite sex.
Studies however reveal that a certain species of spider, mastophora cornigera, mimics the sex pheromone of the moth by releasing a mixture of volatile compounds with which it attracts male moths upon which it preys. So, even though pheromones trigger responses among organisms of the same species, it may be used deceptively across other species.