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was Urtica dioica (stinging nettle) the plant that evolution created as a reaction to humanity?

was Urtica dioica (stinging nettle) the plant that evolution created as a reaction to humanity? - Botany Forum

was Urtica dioica (stinging nettle) the plant that evolution created as a reaction to humanity? - Botany Forum


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  #1  
Old 08-05-2007, 06:23 AM
a_plutonium
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Default was Urtica dioica (stinging nettle) the plant that evolution created as a reaction to humanity?



Last week I encountered a patch of stinging nettle and had my hand
irritated for some hours. For those
unaware of stinging nettle, it is a plant with needles on its stem and
tipped with acid so as the
hand or legs brush against this nettle, the skin is irritated.

I have a question on stinging-nettle. What animal caused the evolution
of this stinging plant? Is it grazing animal
such as rabbits or some hoofed grazer? I tend to think stinging nettle
evolved because of the prescence
of humans? I wonder if stinging nettle is due solely to the prescence
of humans? That planet Earth would
not have stinging nettle if not for humanity. And whether there are
biological firsts for stinging-nettle and
Homo sapiens.

Question: is that true? Second question: If true then how old is this
co-evolving relationship?

Archimedes Plutonium
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whole entire Universe is just one big atom
where dots of the electron-dot-cloud are galaxies

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  #2  
Old 08-06-2007, 12:04 AM
mel turner
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Default was Urtica dioica (stinging nettle) the plant that evolution created as a reaction to humanity?

"a_plutonium" <[Only registered users see links. ]> wrote in message
news:1186295035.660573.55150@x35g2000prf.googlegro ups.com...

Ouch!


Not exactly. The hairs are actually like stiff little hypodermic
needles with glassy walls and a tip that neatly snaps off on contact
so that the hair's contents are injected into the tiny wound the
hair makes.


Why not both, or potentially plant-damaging animals in general? The
tiny needles with painful nerve-stimulating juice inside might work
just as well on almost any animals. This article suggests that the
stinging hairs defend against mammals but not insects:

[Only registered users see links. ]


Why humans? There seems to be no reason to think the nettle's stinging
hairs have evolved in any specific relationship with humans. There are
plenty of other animals out there to be stung.


Again, why think it has anything specific to do with humans?


The stinging-hairs type of defense has evolved independently in
several different groups of plants. Even in true nettles [family
Urticaceae] there are numerous stinging species in several genera
as well as many non-stinging genera.

[Only registered users see links. ]
[Only registered users see links. ]
[Only registered users see links. ]
[Only registered users see links. ]

Besides "true" nettles, there are similarly very nettle-like stinging
plants in the Euphorbiaceae [e.g., Tragia, Cnidosculus] the Loasaceae,
and perhaps some other families.
e.g:
[Only registered users see links. ]

Many other plants have other sorts of irritating hairs that likely
also play a defensive role.

Some of these adaptations are undoubtedly fairly old [in true nettles,
cladistic analyses may tell us whether stinging hairs would have been
present in the last common ancestor of all modern stinging Urticaceae].

One neat thing worth pointing out is that nettles and similar plants
are genuine examples of _venomous_, not merely poisonous, plants.

cheers


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  #3  
Old 08-06-2007, 12:47 AM
Jack Campin - bogus address
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Default was Urtica dioica (stinging nettle) the plant that evolution created as a reaction to humanity?

> I have a question on stinging-nettle. What animal caused the

Caterpillars, perhaps?

============== j-c ====== @ ====== purr . demon . co . uk ==============
Jack Campin: 11 Third St, Newtongrange EH22 4PU, Scotland | tel 0131 660 4760
<http://www.purr.demon.co.uk/jack/> for CD-ROMs and free | fax 0870 0554 975
stuff: Scottish music, food intolerance, & Mac logic fonts | mob 07800 739 557
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  #4  
Old 08-06-2007, 01:43 AM
Charles
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Default was Urtica dioica (stinging nettle) the plant that evolution created as a reaction to humanity?

On Mon, 06 Aug 2007 01:47:14 +0100, Jack Campin - bogus address
<[Only registered users see links. ].uk> wrote:



deer
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  #5  
Old 08-06-2007, 08:16 PM
a_plutonium
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Default grasshoppers the likely intended victims of nettle Re: was Urtica dioica (stinging nettle) the plant that evolution created as a reaction to humanity?


mel turner wrote:

Thanks for the long and detailed discussion. I am wondering how far
back
the stinging nettle lines go in history. Whether they existed before
humanity
existed.

I noticed the cat eating some nettle in springtime, unless I have it
confused
with wild mint. So maybe cats enjoy the nettle acid tipped needles.

I notice my horse, donkey and Llama refuse to eat nettle. Even when I
try
to place nettle before an apple where they refuse to bite into the
nettle. Maybe
the donkey ate some nettle, not sure of that fact?

What I am guessing from my potato patch next to a cucumber patch where
the grasshoppers mowed down the potato leaves but left the cucumber
untouched.

I am guessing that stinging nettle co-evolved with grasshoppers. And
the nettle is
targeting grasshoppers. But I would need some understanding as to how
nettle
hyperdermic needles penetrate a grasshopper or ward off grasshoppers.

The positioning of the needles appears to be a position targeting
grasshoppers.

But grasshoppers mostly have a hard crusted body so how would the acid
of the
nettle play into the grasshoppers body?

Is the age of the nettle classes about the same in historic time--
hundreds of million
of years as the age of grasshoppers? So is there some geological time
age of nettles
that closely follows the time age of grasshoppers?

Obviously if nettles go back hundreds of million years then human
species was not
the evolutionary impetus, but if grasshoppers follow a similar time-
line, then it is grasshoppers
that are the intended victims for stinging nettle.

What I am trying to do is find out the "intended victims" for stinging
nettle.

Archimedes Plutonium
[Only registered users see links. ]
whole entire Universe is just one big atom
where dots of the electron-dot-cloud are galaxies

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  #6  
Old 08-06-2007, 10:10 PM
Ron Hardin
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Default grasshoppers the likely intended victims of nettle Re: was Urtica dioica (stinging nettle) the plant that evolution created as a reaction to humanity?

A.E.Housman has a nettle poem, in fact
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--
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On the internet, nobody knows you're a jerk.
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  #7  
Old 08-07-2007, 06:42 AM
a_plutonium
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Default grasshoppers the likely intended victims of nettle Re: was Urtica dioica (stinging nettle) the plant that evolution created as a reaction to humanity?

According to this website of a team of researchers:

Responses of Invertebrate Herbivores to Stinging Trichomes of Urtica
dioica and Laportea canadensis
Tracey D. Tuberville, Peter G. Dudley, A. Joseph Pollard
Oikos, Vol. 75, No. 1 (Feb., 1996), pp. 83-88
doi:10.2307/3546324
This article consists of 6 page(s).

They hypothesized that Urtica evolved more as a response to mammals
than to insects.

But I do not see how Urtica can penetrate the thick hides of most
grazing animals. I doubt that
stinging nettle would penetrate deer or buffalo.

As for mice and rodents, they would not do enough damage to the plant
to bother with.

So that leaves insects such as swarms of grasshoppers.

So I would have my bets not on mammals but insects and especially
grasshoppers.

Unless the stinging nettle works on the mouth and tongue of a mammal.
For humans it
would be the skin, since we are not eating nettle. So maybe it is the
mouth and tongue
of mammals that the nettle is targeting.

And then, of course, the evolution of the nettle was to ward off all
herbivores be they
mammals or insects.

Maybe the chemicals involved tell us who the targeted victims are?
Some say histamine
and acetocholine and folic acid are involved. So does anyone know if
these chemicals
target the mouth of a mammal or the mouth of a insect?

Perhaps the toxic chemicals involved tell us which mammals and insects
co-evolved with
stinging nettle.

Maybe the chemicals were not designed to penetrate grazing mammals but
were designed
for scent so that a deer or buffalo smell the toxic chemicals and
avoid eating the plant.

Or, perhaps, the chemicals were designed to insects such as
grasshoppers that when
they traverse the plant some of those chemicals get on their bodies
and they irritate them.

I have never seen a grasshopper on the stems of any stinging nettle,
so I would bet it is
grasshoppers that are the main target of nettle.

Archimedes Plutonium
[Only registered users see links. ]
whole entire Universe is just one big atom
where dots of the electron-dot-cloud are galaxies

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  #8  
Old 08-07-2007, 12:16 PM
spamlet
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Default grasshoppers the likely intended victims of nettle Re: was Urtica dioica (stinging nettle) the plant that evolution created as a reaction to humanity?

A related point might be to ask where the nettle used to grow before
men started building latrines and spreading fertiliser everywhere!

S


a_plutonium wrote:

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  #9  
Old 08-07-2007, 03:53 PM
monique
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Default grasshoppers the likely intended victims of nettle Re: was Urticadioica (stinging nettle) the plant that evolution created as a reaction tohumanity?

Archie, don't think hide, think mouth: The muzzle, lips, gums, and
tongues of grazing animals are just as affected by nettles as bare human
skin.

M. Reed

a_plutonium wrote:

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  #10  
Old 08-07-2007, 05:53 PM
a_plutonium
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Default grasshoppers the likely intended victims of nettle Re: was Urtica dioica (stinging nettle) the plant that evolution created as a reaction to humanity?


monique wrote:

Okay, and what would you say for grasshoppers and insects? Would it be
their mouthparts
and sense of smell and their "face area"? This should be easy enough
to research and find
a definitive answer as to how nettle evolved to ward off herbivores,
whether they be mammal
or insect.

The breaking off of the tip of the hyperdermic needle of nettles
suggests the intended victim
is when the mouthparts of the insect try to eat. And that it was not
intended to pierce human
skin but found it beneficial to the nettle. So I think the hyperdermic
needle geometry was
evolved for insects with the slightest touch would create the needle,
but that the needle
shape would also ward off humans.

I have never seen grasshoppers on nettle plants. I think grasshoppers
were the co-evolving
animal.

Archimedes Plutonium
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whole entire Universe is just one big atom
where dots of the electron-dot-cloud are galaxies

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created , dioica , evolution , humanity , nettle , plant , reaction , stinging , urtica


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