A recent paper (free access) by Associate Professor Susan Dudley, published in the Royal Society journal Biology Letters argues that some plants recognize their kin.
Kin recognition is important in animal social systems. However, though plants often compete with kin, there has been as yet no direct evidence that plants recognize kin in competitive interactions. Here we show in the annual plant Cakile edentula, allocation to roots increased when groups of strangers shared a common pot, but not when groups of siblings shared a pot. Our results demonstrate that plants can discriminate kin in competitive interactions and indicate that the root interactions may provide the cue for kin recognition. Because greater root allocation is argued to increase below-ground competitive ability, the results are consistent with kin selection.
Although it were gardeners who knew this all along:
Gardeners have known for a long time that some pairs of species get along better than others, and scientists are starting to catch up with why that happens,” says Dudley. “What I’ve found is that plants from the same mother may be more compatible with each other than with plants of the same species that had different mothers. The more we know about plants, the more complex their interactions seem to be, so it may be as hard to predict the outcome as when you mix different people at a party.”
Source: Plants recognize their siblings, biologists discover at PhysOrgForum
yeah, that last quote was probably a bit of colloquialism for the press article.
botanists have known about allelopathy beteen heterospecifics for decades, at least.
I find it very strange that a simple experiment to test for kin selection in plants like this had never been done before.
if correct, it’s definetly one of those “Doh! why didn’t I think of that!” moments.
I’m hoping someone more up to date with the botanical lit. can shed more light on this.
That *proves* Dr. Egnor assertion that altruism is NOT in the brain !
I realize that is a joke (and it’s not bad), but it got me thinking…
In fact what things like this SHOULD do is make people think twice that behavior itself requires some sort of brain for processing feedback.
that plants have behaviors has been known for many decades.
Of course, the definition of altruism as kin selection only is a subset of the whole.
Hamilton logically predicted altruism in systems where there physically would be mechanisms for kin recognition, and where kin were in common contact, and lo and behold, that’s what we’ve found for the most part in the intervening years.
the argument extends from there to consider whether altruism in cases where there is demonstrably no kin relationship is really just a hold-over from kin-selection, where there have been no significant counter selective pressures, or whether there are reasonable expectations in any given system of a “return on investment”, or whether there is yet another explanation for it in these cases.
taking a look at social interactions and apparent altruism in vampire bats tends to help one think through the various possibilities.
bottom line though, especially when kin selection is demonstrated, is that it’s obvious that supernatural influences are simply not needed to explain the behavior.
Pim-
this is actually a question that really needs to be resolved:
Is this REALLY the first instance of Kin Selection demonstrated in plants?
you have access to the lit.
can you do a quick search in the bot lit to see if “kin selection” comes up with any hits?
thanks
Nope, what is first is Kin Recognition
and
Donohue, K. 2003 The influence of neighbor relatedness on multilevel selection in the Great Lakes sea rocket. Am. Nat. 162, 77-92 (doi:10.1086/375299).
Donohue, K. 2004 Density-dependent multilevel selection in the Great Lakes sea rocket. Ecology 85, 180-191.
Goodnight, C.J. 1985 The influence of environmental variation on group and individual selection in a cress. Evolution 39, 545-558 (doi:10.2307/2408652).
Kelly, J.K. 1996 Kin selection in the annual plant Impatiens capensis. Am. Nat. 147, 899-918
Stevens, L., Goodnight, C.J. & Kalisz, S. 1995 Multilevel selection in natural populations of Impatiens capensis. Am. Nat. 145, 513-526 (doi:10.1086/285753).
Waldman, B. 1988 The ecology of kin recognition. Annu. Rev. Ecol. Syst. 19, 543-571 (doi:10.1146/annurev.es.19.110188.002551).
Remember this is but a first study, 4 pages long, of kin recognition in plants. Still a cool experiment.
Source: Plants Can Recognize, Communicate With Relatives, Studies Find, National Geographics.com
There’s that pervasive cephalocentrism rearing its ugly … erm … head again.
then here’s a question for you Pim:
how would kin selection proceed without kin recognition?
IOW, the question just moves a level lower, but is still just as perplexing as to why this is apparently the first study to look at this issue.
I’m still skeptical, not of the study, but that it is in fact the first of its kind.
Kin selection is HUGELY well studied topic in animal behavior, so I’m still a bit skeptical that the issue of kin recognition hasn’t been looked at in plants before now.
for example, the 88 waldman paper likely touches on previous studies looking at this issue in plants.
do you have access to that?
I believe that we need to distinguish between detecting kin selection which can be detected using statistical methods, and direct detection of kin recognition by including relatedness into the equation.
and
and the discussion part
No, pim, you are confusing proximal mechanism with ultimate explanations, rather than looking at whether the issue of kin recognition (as a proximal mechanism required for the evolution of kin selection) has been found in plants before.
again, although the question has become more specific, it still remains:
is this really the first time kin recognition has been demonstrated in plants?
I realize you aren’t an expert in animal behavior, but to compare, if someone released a study that claimed to be the first to analyze kin recognition in animals, everyone in my field would have had a hearty laugh.
so the question is, is this really the first, and if so, what the hell took so long, as it seems a pretty obvious issue to be testing for.
I don’t see how I can be much clearer than that, but if you can figure out what might make it so, please ask.
I’ll guess that gardiners have kinda known about this for hundreds, if not thousands, of years.
How much clearer than
please note:
we seem to be missing each other. I’m getting the impression you think I am personally attacking this paper.
I’m not. I’m merely curious as to the veracity of this statement:
since I know quite a bit about the the study of altruism and kin selection in animals, and it surprises the hell out of me, given the vast amount of literature on this on the animal side.
If verified, the next obvious question would be:
why not?
was it just overlooked?
were there technical issues in the way (the 88 paper suggests not, but I haven’t read it)?
maybe it’s just a perspective difference between the two of us, but aren’t you even the slightest bit curious about whether if this is the case, how the study of kin selection got so far separated between animals and plants?
Source
No publications found so far for Tonsor and Phytolacca should be 1989 Ah there we are
Tonsor S. J. 1989 Relatedness and intraspecific competition in Plantago lanceolata. American Naturalist 134: 897-906
Tonsor, S.J. (1989) Relatedness and intraspecific competition in Plantago lanceolata. Am. Nat. 134:897-906
And then
yes, I think I see what you’re getting at. for example, this paper concluded that there was kin selection, but didn’t investigate the actual mechanism used in kin recognition.
correct?
similar pattern in the latter papers suggests increasing recognition of what the mechanisms might be, without actually testing for them.
Is this what you’re finding?
like I said, I’m not familiar with the bot lit, only the animal lit, and the various mechanisms of kin recognition in animals has a decent body of publications associated with it.
I do not believe that the recent paper has determined the kin recognition method either. Both planted related and less related plants together in pots to determine growth and other variables. Both found more competition the less kin relationship. So far the only new aspect is the root part.In the older paper, the root mass was discarded since it was to entangled.
I’ve been on the periphery for quite a while, but my impression is that whole plant studies involving the weight of roots and shoots were mainly carried out in the 50s and 60s. The emphasis then moved on to allelopathy and biochemistry. Root studies are difficult. Washing the soil out of roots is both messy and tedious, and virtually impossible if there is macroscopic organic matter in the soil (when I did it, we used a nearby stream) and publications tend to comes slowly so the area seems to have been selected against. But I agree, now it’s been done it is obvious that there was a large gap.
I only read through the followup comments quickly, so forgive me if I restate someone else’s argument.
It seems to me that “kin recognition” is not the same as “producing an effect which is more pronounced versus non-kin”. I might hypothesize that, in this study, all plants in the study produce allelochemics. The genes for production are linked (perhaps functionally as well) to the genes for “dealing with” allelochemicals. And thus, allelochemics have little, or less, or no, effect on closely related plants (who share the genes for production/dismantling), and more effect on less related plants.
One might examine, say, mixed plantings of related plants with a mixture of related and non-related plants, compared to plants mixed solely with non-related plants. If “recognition” is involved, one would predict something like this:
B planted with B –> baseline growth rate for B A planted with B –> B’s growth reduced by X A planted with A & B –> B’s growth reduced by between 0 and X A planted with A –> baseline growth rate for A
One would want to fill out the table the other way as well: B planted with A around it, and B planted with mixed A and B around it.
This completely mechanistic and, to my mind, lacking in “recognition” hypothesis is worth considering and eliminating.
-Josh
The key here is the difference between demonstration, which is inferential, and direct detection. It’s sort of like the difference between demonstrating that humans and chimps have a common ancestor and, as the creonuts put it, “being there”.
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