I have searched few authentic books and have found the following difference between them.
Signaler pheromone induces fast reaction in the recipient and the Primer induces slow reaction.
But I did not find any book that discriminates their function.
P.S. I have read Wikipedia and I'm not counting on it.
A good example of a primer and a signaler pheromone could be in the recently discovered pheromone system in pennate diatoms (unicellular algae). When diatoms reach a certain size as a result of successive divisions (they get smaller with each vegetative division) both mating types start to produce a first pheromone that provokes cellular responses in their mates: 1) to stop dividing vegetatively and 2) to produce either another pheromone (a cell attractant, by one of the mating types) or to induce a sensing system to locate their mates. So, the 'Primer' pheromone would be the first, and the 'Signaler' the second pheromone, i.e. the attractant. A similar system exists in fungi. The evolutionary explanation is likely that organisms don't need to invest in pheromones and their associated repertoire of sex genes when mates are not present.
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