Wednesday, August 08, 2007

Pirate ants (Polyergus breviceps) and sympatric hosts (Formica occulta and Formica sp. cf. argentea): host specificity and coevolutionary dynamics

From the Biological Journal of the Linnean Society, 2007, 91, 565–572:

Abstract: The pace and trajectory of coevolutionary arms races between parasites and their hosts are strongly influenced by the number of interacting species. In environments where a parasite has access to more than one host species, the parasite population may become divided in preference for a particular host. In the present study, we show that individual colonies of the pirate ant Polyergus breviceps differ in host preference during raiding, with each colony specializing on only one of two available Formica host species. Moreover, through genetic analyses, we show that the two hosts differ in their colony genetic structure. Formica occulta colonies were monogynous, whereas Formica sp. cf. argentea colonies were polygynous and polydomous (colonies occupy multiple nest sites). This difference has important implications for coevolutionary dynamics in this system because raids against individual nests of polydomous colonies have less impact on overall host colony fitness than do attacks on intact colonies. We also used primers that we designed for four microsatellite loci isolated from P. breviceps to verify that colonies of this species, like other pirate ants, are comprised of simple families headed by one singly mated queen.

Authors: JEREMY M. BONO, RUMSAIS BLATRIX, MICHAEL F. ANTOLIN, and JOAN M. HERBERS, Colorado State University, Fort Collins, CO, USA


Image: poster from the animated film Bad Bug Bee and the Pirate Ants. Coincidentally, while searching for this image, I discovered that there apparently is a rugby team in Kolkata, India, that is named the Pirate Ants. Frickin' awesome!


  1. These are not pirate ants; they are slave-maker ants, a term that has been used for over two hundred years. Why the term is being changed here is a big mystery.

  2. Well, Anonymous: Polyergus, like human slave owners, are work-parasites of their hosts, but there the analogy ends. If you think about it, neither "slave-maker" nor "pirate" is a good analogy. Slavery and piracy are both intraspecific interactions, and the behavior of Polyergus, etc. is more like forced, heterospecific domestication (and sterilization?). Some folks, mostly non-myrmecologists except for Joan Herbers, have argued that the term slavery (and its Greek-derived rough equivalent, dulosis) are politically incorrect and insulting/hurtful/offputting to those who are, or whose ancestors were, subject to slavery, which may be true, but certainly this could be said for piracy, too. So that in a nutshell is why the terminology change, and I agree it's not a good or useful one, but still am not quite sure what to do with the long-traditional, but admittedly inappropriate term slave-making.

  3. hello, I'm from Kolkata, our team is a street children team, and the children have choosen the name because their are very small but very furious, and onces they get the ball you can try anything you want, but you won't get it back. Nothing to see with the slaving or parasitings bugs that you are studying. I am a little bit disapointed I must say...

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