Olfactory, gustatory and pheromone systems 3

Flies have different sensory systems which can be divided into two categories: generalist and specialist systems. Generalist system responds to general chemical such as sugar and bitter that exist everywhere. This category includes olfactory and gustatory systems. The specialist system refers to pheromone system, in which those neurons respond to pheromones. The reason it is called specialist system is that pheromone system responds to pheromone strictly from the same species and single neuron responds to only one single type of pheromone so it is highly specific.

Pheromone can trigger a lot of behaviors.

• Aggregation.  Animals can get together to fight or threaten the predators. They express pheromone to recruit their partners.
• Sex. Females can release pheromone to notice the males that they are ready to mate. The pheromone can be sensed from miles away.
• Trail. Ants can leave pheromone on the way home with the food. So that other ants can track the signal to find and carry the food home.
• Territory. Dogs and cats have their pheromone in their urine. They put the signal at the border of their territory to demonstrate there is an occupant here.