Some Background on the Slave-Making Ants

The phenomenon of slavery in ants is captivating, and the fact that it is limited to a few species of ants in Northern temperate climates is biologically interesting. This site explores the process of enslavement and the transpiring behavioral relationships of both the parasitic, slave-making, and host colony, slave-made, ants. For this website emphasis is placed on the relationship Protomognathus americanus (P. americanus) have with their Leptothorax longispinosus (L. longispinosus) neighbors (the host colony ants they are socially parasitic towards), but also discusses slave-making relationships in other ant species also known to participate (e.g. Leptothorax curvispinosus, and Leptothorax ambiguus). Here we tie together previous research conducted on slave-making ant colonies and go through an in depth analysis of this remarkable animal behavior using Tinbergen’s four questions on phylogeny, ontogeny, mechanism, and survival value. Possible implications are also discussed about the relevance of the behavior in each of the questions, as well as what necessary future research should be conducted to find out more about this particular behavior. While these ants are a particularly good source for studying this behavior, other insects also exhibit this type of enslaving phenomenon and we encourage you to explore other ants, other ant behaviors, or other bugs and insects as well.
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Figure 1. P.americanus ant and the Leptothorax ant population it has enslaved after successfully raiding their colony.


About the Slave-Making P. americanus Ants

P. americanus ants are characterized by being a small blackish-brown color with a distinct groove that runs along the side of their head. A typical group of invading P. americanus ants consists of a queen and around three or four worker ants for about every 45 slave made Leptothorax ants. The P. americanus worker ants are almost always larger than the Leptothorax ants and both species are geographically found in Northeastern regions of the United States and the surrounding Canadian areas, such as lower Ontario and Quebec. Both females and males are known to be highly aggressive when scouting and raiding other possible host colonies.



Figure 2. A typical Protomognathus americanus slave-making female ant

Tinbergen's Four Questions Visualized

As mentioned before the exploration of the phenomenon of this behavior will be guided by the use of Tinbergen’s four questions, which inquire about how a behavior developed over evolutionary time and it’s ultimate purpose (phylogeny), how a behavior develops over an organism’s lifetime (ontogeny), the functioning behind a behavior and/or characteristic(s) (mechanism), and the use of a behavior or characteristic in the survival of an animal (adaptive/survival value). In Figure 2 below, these questions are outlined for a more visual representation.



Figure 3. Visual diagram outlining Tinbergen’s four questions. Adaptive Value is interchangeably used with Survival Value.