Thursday, August 6, 2020

But what is a "superorganism," in the end?

What is a superorganism, exactly?

I was mulling over this question and I came up with the classic example: the ant colony is supposed to be a superorganism in the sense that all the organisms in it share the same genome, just like in a human beings all cells have the same DNA (except mitochondria, of course).

But no, wait! That cannot be: ants are sisters, not clones. They may even have different fathers. For a quirk of the genetic setup of male ants, ant sisters share 75% of their genes, not 50% as human siblings do. But they are not clones. So an ant colony is not a superorganism, but a kind of tightly knit holobiont.

But then, a discovery: that's not true, either! As reported in this paper, there are ant colonies where all the ants are clones of each other! Unbelievably, some ants have discover tricks to completely eliminate the need of males: yes, no males and no queens. They reproduce by parthenogenesis. These colonies are true superorganisms, not holobionts. And I keep discovering new things: one that starts to be very common is that males seem to be obnoxious and useless in all species!




3 comments:

  1. And the ants practice crop rotation, switching between different fungal food crops.

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  2. In discussing ants, we should remember that we are discussing something like mammals. Just like mammals, there are many different kinds of ants.

    I regard a red harvester ant colony as an organism. These ants do not reproduce. The colonies reproduce. These ant colonies are not social. They establish and defend individual territories (like many non-social mammal carnivores). The only "cooperative" interaction between these colonial organisms is the annual mating to generate new colonies.

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    Replies
    1. A bit like tribes, each with their own territory, but meeting once a year to freshen their gene pools.

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Who

Ugo Bardi is a member of the Club of Rome, faculty member of the University of Florence, and the author of "Extracted" (Chelsea Green 2014), "The Seneca Effect" (Springer 2017), and Before the Collapse (Springer 2019)