Scientists investigate how chemicals evolved into communication signals

Living things possess many diverse ways of communicating, but perhaps the oldest and most widespread form of communication involves the use of chemicals. From animals and plants to bacteria and fungi, organisms emit and receive chemical signals as a way of transferring information between one another. Organisms are sensitive to a very broad range of chemicals; for example, scientists estimate that rodents can detect thousands or even tens of thousands of odorant molecules.

As the scientists explained, chemical information can be found in mammal excrement, insects' cuticles, spider silk, plant nectar, and so on. Other organisms detect the chemical information in these substances to gain information. For example, red harvester ants have different chemicals in their cuticles that can reveal to other ants whether they are foragers or nest-maintenance workers. And wolves' feces contain sex hormone levels that indicate their status within the pack to other wolves.

Source:

http://www.physorg.com/news/2011-01-scientists-chemicals-evolved.html