A popular household fern may be the first known eusocial plant
blog.pnas.org
blog.pnas.org
> Eusociality exists in certain insects, crustaceans and mammals.
https://www.ted.com/talks/suzanne_simard_how_trees_talk_to_e...
> One key question is what defines an individual fern. If a colony can begin with a small plume of strap fronds sticking up from a few nest fronds and then spread asexually on the same roots, perhaps it is a single plant
There is a lot of talk about the amazing cooperation of these plants. And then they say it is actually one plant. Is it interesting if one plant grows different leaves at different heights?
On practice the only difference is on the level of collaboration. You get a similar phenomenon here, it's different because those plants collaborate less than the leaves of a single plant, so we give them a different name. From that point of view, this finding is quite boring. What makes it interesting is that it's an independent evolution of collaborative behavior.
In the same paragraph, clones, not the same plant. Strawberries clone themselves. They aren't the same plant.
"The difference, Burns says, is that the whole strawberry patch looks the same. The ferns, by contrast, differ markedly in morphology and reproduction depending on their role in the colony." (emphasis mine)
Right underneath the paragraph you were quoting, they have different roles, not just different heights.
Also,
"Drawing conclusions about staghorn social organization may ultimately hinge on the nuances of eusociality—some definitions frame the concept as more of a spectrum, notes evolutionary biologist Guy Cooper, at the University of Oxford in the UK, who was not involved in the fern study." (emphasis mine)
So I guess its significance depends on how you define "eusocial".
In fact this depends a lot on the location, soil and age of the clones.
> The ferns, by contrast, differ markedly in morphology and reproduction depending on their role in the colony."
First of all, population is not the same as colony.
Second, many plants have auxiliary structures (temporary, marcescent or permanent). The concept of bract, thorn, nectarium or stipula is not a strange one for botanists but those are parts of one individual, not individuals in a colony.
Is well known that gametophytes and sporophytes are different individuals. Many algae and ferns have it. If we want to bend the concepts for non useful reasons, then any pregnant woman should be called an "eusocial colony" with three individuals.
As for tautology, I am claiming that we are attributing intent (a human characteristic) to an object. I think I used the term correctly. That behaviors of objects should not in general be allowed to be equated with human behavior leading to therefore imply human-like intent. I think this is a good idea in science.
In my case I was trying to forward the idea of these two being at a different scale was a differentiator. And that the ants therefore were better candidates for such human like behavior than a plant.
However a studying biology major set me straight on that and introduced what I think is a better criteria for looking at these systems. She said the underpinning work focused on these colonies establishing communication mechanisms. And while anthropomorphizing systems is frowned upon, in this case that might be an overly strict rule. After all both communication and conscious intent are both associated with humans.
In computer science we fearlessly anthropomorphize with our names (actors, agents, managers). Why that should be not be frowned upon, but disallowed for plants therefore seems less and less obvious. So I think my concerns are unwarranted.
ALL ferns have complex life cycles with 2 different lifes, (not only the Platycerium). A plant called gametophyte normally short lived and tiny, and another plant called sporophyte that we call fern. Botanists know that since thousands of years ago. There is nothing in Platycerium different or strange.
They just aren't understanding what is an individual. A leaf is not an individual and your hair is not a society of hair that grow in the same direction following the orders of a hairbee queen.
Equaling animals and plants and finding a "soul" in everything (for fame and money none less) is getting more and more annoying each day. I wish we could focus in the real problems of the biology, instead to try to rebuild mythology.
I think you should write a letter to the editors at Ecology, where the actual paper was published.
I wasn't looking to email you, but just to say your bio mentions your 'email below', but doesn't then specify one.
The email field in HN profile edit form is actually private, to display an email address you need to put it separately (and probably want to obfuscate it) in the general bio text area.
At some point, another one, just like it, appeared across the street (probably a good 100' away) growing on a corner side of another house at the same vertical height.
Many years later, it is also huge and doing really well. It has never been watered or cared for because it is impossible to reach from the ground without a ladder. It also hasn't seemed to spread further, yet.
The morphology of the ones at the top could simply be explained by local environment (more access to sun and water and a need to regulate water intake, both increase access and shed excess). The ones lower would be driven by similar epigenetic expression to take advantage of a different environment (less sunlight, try to collect and retain the diminished amount of water arriving.
To consider the growth a true colony we’d have to answer the question: how do the ones at the bottom provide benefit to the ones at the top and what is the incentive for the ones at the top to have water-shedding disk fronds as a way of helping those below (as opposed to simply for the upper plants’ “selfish” reasons)?
The only possible answer is that the lower ones would have to spread their dna (which they share with the upper ones) more widely than the upper ones can on their own. Which is possible but unproven.
Thinking solely about throughfall can be misleading- exposure dominates by driving drying.
They can be pressed through a sieve so that the cells split apart and move as individuals. The cells will reform the organism. Two trichoplax organisms can be split like this and the cells from each will reform with each other.
Even my chicken would fit in that description.
Eusociality is like bees that don't reproduce but support a queen that does. With that in mind:
> “[Ferns] at top seem to be water and nutrient capturers; ones below seem to store water.” [...] the number of reproductive [leaves/ferns] increased with the height of the colony, and 40% percent of ferns didn’t reproduce at all. Reproductive division of labor
For textbook eusociality, there are two more conditions that have not yet been proven to be met by ferns. However, more interesting perhaps is
> what defines an individual fern. If a colony can begin with a small plume of strap fronds sticking up from a few nest fronds and then spread asexually on the same roots, perhaps it is a single plant
There is an argument to be made that they're not a single plant, because
> [The ferns] differ markedly in morphology and reproduction depending on their role in the colony.
So it hinges a bit on what you call eusocial and what you call a single plant.
The headline made me think that ferns have a queen-like somehow or somewhere, and while there is some division of labor... the jury's still out on which definition it'll fall under, and it'll probably just end up being a footnote in a biology book somewhere.
In conclusion, the interesting takeaway to me is that different ferns support each other, and 40% of them don't reproduce at all. There is a parallel to be made with how bees don't individually all reproduce, but whether the mechanism is actually identical to a meaningful extent is yet to be debated.
Plants can reproduce asexually and ferns do it all the time.
Occam's razor would suggest that exposure to light, orientation relative to gravity, etc are more likely causes for the divergent characteristics of ferns at different positions, not any kind of purposeful social organization.
Occam's razor could equally well be used to cut out the dependence on consciousness for the development of eusocial behavior.
do we ascribe the eusocial organization of ants to conscious decisions made by individual ants?
Ants do not apply their conscious intelligence to choose whether to become a worker drone or soldier drone; it is controlled by chemical signals. Bee hives feed royal honey to form a new queen when the colony lacks a queen or is so large it may be able to split... but none of that is "conscious".
Exposure to light, orientation relative to gravity, and such likely ARE the direct causes of the ferns' different growth patterns. But the end effect of a property that says "if you get light from above, grow waxy leaves that help filter water into the clump" is (maybe) that the clump consists of "cooperating" individuals and does better than individual fronds would.
From what I know of antkeeping, this isn't true and they actually do make a conscious decision. (Based on things like food availability, perceived threat, etc.)
But, on reflection, I'm not going to disagree with you. I'm not sure that the word "conscious" actually has a clear meaning other than human exceptionalism.
Conscious behavior emerges from a set of cell signaling subsystems borrowed from plants and re-purposed...
Those subsystems are known as the nervous system, hormones, neurotransmitters
We as of yet in the continuum of emergent behavior yet to have properly deined where conscious lies
Animals may be able to exhibit more complex behaviour, but it is still mostly just a response to stimuli. An ant doesn't know why it cooperates, it does not have a purpose in a human sense. It has genes that have survived because they encourage social behaviour. It behaves socially in response to stimuli and helps the genes to spread.
Fun thought experiment: what if humans are the same?
When was the last time you did something that didn’t help genes to spread, or wasn’t part of a longer strategy with that as eventual purpose?
Very vague recollection of mine, but I believe there was a study about the role of homosexuality in propagating the species. In very complex social animals likes humans, we can also ask about the reproductive "utility" of such things as art and music, which don't directly contribute to the basic needs of survival.
It is possible that things like art and music are the result of traits in our genome that are beneficial in other ways. Or the traits just didn't inhibit reproduction.
Maybe a hypothetical "gay gene" could have survived in women simply because they historically lacked choice about reproduction.
But the reproduction of those new ideas is not sex based. That is different and can happen much more quickly than evolution. The song of a bird could take thousands of years to change. Humans can make new music in a day that builds on previous culture.
But untangling this all is really interesting.
It is not Occam's razor but a reduction. We do not need to talk about macroparameters in thermodynamics because they can be explained by microparameters. So there are no pressure and temperature, only positions and kinetic energies of individual particles.
"Eusociality" here is not an explanation of a phenomenon, it is not a cause of a phenomenon but a classification. Eusociality doesn't explain (at least in this particular case), it just a mark for the phenomenon to be a member of the wider class of phenomena. At the same time exposure to light, orientation relative to gravity, etc might explain observed eusociality, so they might be targets for Occam's razor.