strange behaviors

Cool doings from the natural and human worlds

  • Richard Conniff writes about behavior, in humans and other animals, on two, four, six, and eight legs, plus the occasional slither.

  • Categories

  • Wall of the Dead

Holy Crap! These Are Some Scary Slave Raiders

Posted by Richard Conniff on January 11, 2014

ZooKeys-368-065-g001

These modern slave-raiders work on the eastern shore of Lake Michigan, up around Traverse City, Michigan, and the secret of their success is traveling light and quick.  They also employ chemical camouflage and have a deft way of murdering anyone that gets in their way.

European researchers discovered this astonishing behavior.  They’ve named the species Temnothorax pilagens, from pilere (Latin): to pluck, plunder or pillage. The paper is just out in the open access journal ZooKeysHere’s the press release

In contrast to the famous slave-hunting Amazon Ants whose campaigns may include up to 3000 warriors, the new slave-maker is minimalistic in expense, but most effective in result. The length of a “Pillage Ant” is only two and a half millimeters and the range of action of these slave-hunters restricts to a few square meters of forest floor. Targets of their raiding parties are societies of two related ant species living within hollow nuts or acorns. These homes are castles in the true sense of the word — characterized by thick walls and a single entrance hole of only 1 millimeter in diameter, they cannot be entered by any larger enemy ant.

An average raiding party of the Pillage Ant contains four slave-hunters only, including the scout who had discovered the target. Due to their small size the raiders easily penetrate the slave species home. A complete success of raiding is achieved by a combination of two methods: chemical camouflage and artistic rapier fencing.

The observed behavior is surprising as invasion of alien ants in an ant nest often results in fierce, usually mortal, fighting. Here, however, in several observed raids of the Pillage Ant, the attacked ants did not defend and allowed the robbers to freely carry away broods and even adult ants to integrate them into the slave workforce. The attacked ants did not show aggression and defence because the recognition of the enemy was prevented by specific neutralizing chemical components on the cuticle of the slave-hunters.

The survival of slave ant nests is an ideal solution from the perspective of slave hunters as it provides the chance for further raids during the next years. In other observed raids chemical camouflage was less effective — perhaps because the attacked ant population was strongly imprinted to a more specific blend of surface chemicals. In fact, a defence reaction was more probable if the attacked colony contained a queen that causes a strong imprinting of chemical recognition cues.

If defending, the chance of a slave ant to win a fight with a Pillage Ant is nearly zero. The attackers use their stinger in a sophisticated way, targeting it is precisely in the tiny spot where the slave ant’s neck is soft-skinned. This stinging causes immediate paralysis and quick death and may result in high rates of casualties ranging from 5% to 100% of the attacked nests’ population, whereas there are no victims among the attackers. If the Pillage Ants can conduct such successful raids with no or minimum own losses, there remains the question which factors regulate their population at a rather low level.

5 Responses to “Holy Crap! These Are Some Scary Slave Raiders”

  1. Soooo? What factors regulate population of the pillage ants, keeps it at a rather low level? And what do they need all the slaves for anyway?

    • Resources are the usual limit on population size, though I’m not sure that’s the case for this species. They raid slaves for the same reason humans do: To get someone else to do their work for them.

      • Of course begs the question, what kind of work? Seems like their biggest work is collecting slaves.
        Insects are so fascinating, didn’t know about these particular ants. I’m ordering your book, sounds interesting form what I see of your writing. Thanks, nice to meet you.

  2. […] you are familiar with the macro photography images of ants heads, like the one I published just the other day, this is like suddenly getting behind the mask, or being invited in to walk around Darth […]

  3. Hi! I’ve been following your blog for a while now and finally got
    the courage to go ahead and give you a shout out from Porter
    Tx! Just wanted to mention keep up the fantastic job!

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s