Written by Ardil Ulucay
Ants can create communities, some of which span from countries to continents, making up roughly 20% of all living animals on Earth, which equals about 2.5 million ants per person. Ants are constantly at war with other ant species or sometimes even with their kind. However, from over 25,000 ant species worldwide, there is a small group of ants that has a different way of dealing with their adversaries and sustaining themselves by enslaving and deceiving other ant species. They don’t clean, build nests, care for their larvae, or hunt to feed themselves and the rest of the colony—The Slaver Ants or the Polyergus.
This peculiar lifestyle challenges the traditional narrative of cooperative ant societies. While most ants thrive on collaboration, the Slaver Ants excel in manipulation and exploitation. The Polyergus species, particularly Polyergus breviceps, exhibits an extraordinary level of parasitic behavior. Upon infiltrating a colony of any other ants the Polyergus queen eliminates the host queen or in some cases the queens and while doing this it covers itself in the scent and the hormones of the nest’s previous queen/queens, this scent convinces the rest of the colony to acknowledge it as their queen and then the Polyergus queen takes over the colony and uses it to lay hundreds of eggs each day. These eggs hatch and create the first generation of slaver ants in that colony.
As we previously mentioned the Polyergus is an evasive and parasitic species. They are unable to provide themselves with food or do the most basic of tasks. Considering that most of the ants the slavers colonize only have a lifespan of a few months at best, the population of slave workers dwindles rather quickly and requires continuous replacements. To meet this large demand the Polyergus ants regularly conduct raids to nearby colonies of other ants. In these raids, the Polyergus eliminates a certain quantity of the colony and then abducts its pupae. The abducted pupae are a critical component in the Slaver Ants' insidious expansion. Once secured during the raid, these pupae are transported back to the Polyergus nest. The new captives, seemingly oblivious to their abduction, hatch into the Polyergus colony. From this point forward, their existence is marked by servitude. The enslaved ants, raised within the Polyergus nest willingly work for their masters, and even feed them directly as some slaver ants are even unable to feed themselves on their own.
The process of turning the kidnapped larvae into functional slaves involves a subtle yet effective manipulation of their social and chemical cues. The enslaved Formica ants, originating from different colonies of the same species, undergo a profound shift in their chemical profiles. Exposure to diverse cuticular hydrocarbons (CHCs) from both their species and the Polyergus ants alters the chemical cues crucial for ant communication.
Remarkably, this chemical exposure doesn't instigate aggression but rather cultivates a heightened tolerance for different CHCs in the enslaved ants. It is this newfound chemical cue tolerance, a direct result of their rich and varied social environment within the Polyergus colony, that renders the enslaved ants less aggressive and more obedient towards their masters. This chemical process can hinder their minds to the point where they can attack ants from their species since they would see them as invasive enemies, isn’t it?
References:
Natural history of the slave-making ant, Polyergus lucidus, sensu lato in northern Florida and its three Formica pallidefulva group hosts. (n.d.). PubMed Central (PMC). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2999504/
Parasitic ants and their slaves. (n.d.). California Academy of Sciences. https://www.calacademy.org/explore-science/parasitic-ants-and-their-slaves
Just a moment... (n.d.). Just a moment... https://www.science.org/content/article/how-blood-red-ants-became-slave-snatchers
The number of ants on earth has a mass greater than all birds and mammals combined. (2023, July 3). GBH. https://www.wgbh.org/news/national/2022-09-21/the-number-of-ants-on-earth-has-a-mass-greater-than-all-birds-and-mammals-combined
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