We seldom stray from microbial domains, but here is a stunning (and delightful) reason for wandering further afield. After all, examples of parasitism are surely not confined to the Small Things and lessons can be learned wherever they appear. According to a group of researchers from England and Italy, parasites of some ants mimic the sounds made by the queen of a colony. The ants in question are a red European species, Myrmica schencki. Their queens make distinctive sounds by scraping a plectrum across a file, somewhat like a washboard player who makes music by scratching his instrument. Worker ants use the same mechanism to make their own refrain, but they differ enough morphologically from the queens that their instruments produce a recognizably different sound. (The ants can tell them apart. Can you? Click here to download audio clips.) Much like a Zydeco player, the royal performer makes sounds that “elicit benevolent responses from workers, reinforcing their supreme social status.” (Source) This behavior can be observed in the laboratory, using appropriate tapes and speakers.
Like many good strategies that can benefit a species, there are parasites that take advantage of this acoustical communication system. Here, the opportunist is an M. schencki-specific parasitic butterfly, the Mountain alcon blue Maculinea rebeli. Its last instar larvae are carried into the nest by M. schencki workers, where, fed by the workers, they increase in mass fifty-fold and then pupate. Both the pupae and the larvae emit sounds that resemble those of the ant queens, guaranteeing them “high status within ant societies.” This status is not just ceremonial courtesy. When food is scarce, the nurse worker ants serve up their own brood as food for the butterfly larvae.
Acoustic mimicry is just one way that these parasites deceive their hosts. There is also chemical mimicry at play. However, to us, the use of sound for deception in these animals is novel. And beware! Just who is programming your iPod?