Sunday, January 27, 2019

While you were sleeping

“Attenborough and the Empire of the Ants” is a fascinating documentary about ants, narrated by none other than David Attenborough (at the ripe old age of 90). The scientific name of the featured ant species is never mentioned – they are simply referred to as “wood ants” and live in the Jura Mountains in Switzerland. What makes them sensational is that their colonies don´t wage “wars” against each other, something wood ant colonies otherwise do as a matter of course. Rather, the Jura anthills form a constantly expanding “super-colony” with millions of queens and even more worker-ants that all live at peace with each other. Indeed, very often, several queens can be found in a single anthill.

Attenborough claims that the ant queens are *not* genetically related to each other, which strikes me as odd - they are all of the same species, so why don´t the gene pools of the different lineages gradually mix as a result of swarming? If true, this would seem to disprove “Hamilton´s equation”, according to which animals should show altruism only towards their kin, although I suppose you could see the Jura ants as an unusual example of reciprocal altruism instead. Besides, the weird collectivism of the ants, where one colony functions as a virtual “super-organism”, has always challenged evolutionary biologists more used to selection on the individual level.

Later, Attenborough reveals another remarkable fact about the Jura ants: many of their colonies have dispensed with swarming altogether, the queens and winged males mating inside the colony instead, after which the queens simply form a new colony nearby. It was also interesting to note that the queens don´t seem to be in control of anything – rather, they are herded by the workers, which (somewhat flippantly) makes Attenborough say that the ants invented democracy!

“The Empire of the Ants” also hints at a possible evolutionary explanation for the super-colony. Usually, wood ant queens invade the nests of field ants, a different species altogether, and “enslave” them. Ironically, this makes the wood ants dependent on the existence of field ant colonies. The wood ant super-colony, by contrast, is no longer parasitical and can therefore expand deep into the Jura forests, including areas where no field ant has ever gone before. The documentary ends somewhat ominously by Attenborough claiming that we may be witnessing the first step in an ant “social conquest of Earth”.

On the web, I found the claim that all Argentine ants *all over the world* form one vast global super-colony, so who knows, maybe the “social conquest” has already happened, it´s just that Homo sapiens haven´t noticed this time neither…

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