Some species of caterpillars drag its back along the leaf to deter competitors from their territory. It seems that the mechanism of creation evolved from a warning vibration movement. This is the most persuasive argument in favor of the theory that the communication signals can evolve from exaggerated and repeated many times and the usual routine for this kind of action.
Yak Jane (Jayne Yack) from Carleton University (Carleton University) in Ottawa, Canada, and colleagues, conducted a comparative analysis of the genes of more than 30 species of caterpillars. They found that those tracks that have evolved recently - were "Skrebtsov" and allowed to territorial disputes without the use of physical force. They were shaking their ass, scraping and banging on sheet paddle-shaped appendage.
In fact, both species have moved back to their identical during a meeting with an uninvited guest. The difference lay in the fact that some tracks instead of paddle-shaped appendages were pronogi - primitive limbs with which they moved forward during a fight with a rival. According to Jane’s Jaka, this means that the oar-like appendages evolved from pronog that will allow new forms of communication, so that both sides avoid physical confrontation. Hot news, science and technology, the only first-hand.