Slave rebellion

From EESwiki

Within the Forschergruppe "Natural selection in structured populations", I have a project together with Professor Susanne Foitzik. The DFG funds my position and a position for a PhD student. The project starts in Novermber 2008.

Summary

Raids by slavemaking ants, obligate social parasites that use allospecific workers to raise their young, cause severe fitness losses in their hosts. Consequently, hosts have developed defence strategies to avoid parasitation, but it was long thought that selection could not alter the behavior of enslaved hosts. If slaves would stop working, slavemakers would only raid more to acquire additional slaves. Slaves were therefore thought to be caught in an evolutionary trap, where no behavioral strategy could increase their fitness and slave rebellion was predicted to be non-existent in ants. However, we recently showed that Temnothorax slaves, instead of taking care of slavemaker (P. americanus) brood, kill many of the pupae. These killings result in smaller raiding parties, which less frequently attack host colonies. The destruction of parasite brood should increase the slaves’ indirect fitness if neighbouring host colonies are closely related. Hence the evolution of slave rebellion critically depends on host population structure. Here, we propose a thorough analysis of the costs and benefits associated with the killing behavior. We will use population genetic analyses to determine relatedness between host nests in the slavemakers’ raiding range, and study killing propensities in different populations. An analytical model will help to understand the relationship between population structure and the resistance trait “slave rebellion”.

Enslaved T. longispinosus workers attacking and tearing apart a Protomognathus americanus worker pupae (by Alexandra Achenbach).