In article ,
(Peter Robinson) writes:
| Tim Tyler wrote:
|
| ``L. niger workers often carried living aphids away from the attended
| colonies, whereas P pungens removed no aphids...''
|
| I didn't know they did that, but surely that counts as farming?

Or predation?


Regards,
Nick Maclaren.

In article ,
Tim Tyler writes:
|
| [ various references snipped. ]
|
| Ants consume aphid milk, and consume aphid flesh.

That is undeniable.

| They tend many species of subterranean aphids in their nests:
|
| ``Subterranean aphids seem more restricted in the species of their
| mutualist, for example the aphid Aphis maidiradicis was thought
| to have an intimate association with Lasius niger americana
| (Forbes 1894). However A. maidiridicis has since been seen
| to associate with at least five other ant species from two
| genera (Way 1963) and at least 17 species of aphid have been
| found in the nests of L. niger (Schouteden 1902).''
|
| - http://www.msu.edu/~shingle9/NewFile...teractions.pdf

Firstly, we are talking about the UK, and it is likely that L. niger
varies in behaviour with location. But, secondly and more importantly,
you are extrapolating wildly from evidence (even proof) of association
to the claim you make above. "Association" means just that; further
work is always needed to work out what FORM of association it is.

The chalk blue butterfly is associated with ants, but its association
is entirely different.

| What other properties do you think would be needed for these
| ants to qualify as 'farmers' rather than 'herders'?

In this context, "herding" means providing some benefits to existing
aphid colonies in return for either honeydew or culling; "farming"
involves moving them into a separate environment, providing them with
food and so on. I have seen no evidence that supports even the claims
that L. niger moves aphids to new plants, in order to start new
colonies. Oh, yes, it is CLAIMED.

As far as the references go, there are a lot of potential loopholes
in their methodology, and that might account for why there is such a
discrepancy between their measurements of ant benefits to the aphids
and the crop benefits when ants are excluded. Or it might be even
more complex than that ....

I must print out your earliest reference and read it carefully. It
isn't the clearest paper in the world, and I can't see how they get
from their measurements to their conclusions.


Regards,
Nick Maclaren.

Nick Maclaren wrote:
Tim Tyler writes:

| What other properties do you think would be needed for these
| ants to qualify as 'farmers' rather than 'herders'?

In this context, "herding" means providing some benefits to existing
aphid colonies in return for either honeydew or culling; "farming"
involves moving them into a separate environment, providing them with
food and so on. I have seen no evidence that supports even the claims
that L. niger moves aphids to new plants, in order to start new
colonies. Oh, yes, it is CLAIMED.

According to reports, such evidence is in:

``Ant-mediated dispersal of the black willow aphid Pterocomma
salicis L.; does the ant Lasius niger L. judge aphid-host quality?''

http://www.ingentaconnect.com/conten...00002/art00014

One such report:

``The ability of L. niger to assess the.
‘health’ of tended aphid colonies was shown by
Collins and Leather (2002) who reported that
ants could remove healthy aphids to start new
colonies if the if the original aphid colony
became overcrowded.''
--
__________
|im |yler http://timtyler.org/ Remove lock to reply.

In article ,
Tim Tyler writes:
|
| One such report:
|
| ``The ability of L. niger to assess the.
| ‘health’ of tended aphid colonies was shown by
| Collins and Leather (2002) who reported that
| ants could remove healthy aphids to start new
| colonies if the if the original aphid colony
| became overcrowded.''

Yes, I know :-(

But I have never seen one of those that was worth a damn, because
they all proved their results by assuming it. There may be an
exception, somewhere, of course.

The papers you have referenced (and others) definitely indicate that
L. niger does assist aphids under at least SOME circumstances, but
my observations indicate that it is a rarer and less important
situation than is often claimed. And the few references I have seen
to whether it is significant in practice have all come down on the
side of "no, it isn't".

That conflict makes me certain that things aren't as simple as they
are made out, which in turn implies that either or both of your and
my beliefs are likely to be effectively wrong.


Regards,
Nick Maclaren.

Nick Maclaren wrote:

In article ,
(Peter Robinson) writes:

| Tim Tyler wrote:
|
| ``L. niger workers often carried living aphids away from the attended
| colonies, whereas P pungens removed no aphids...''
|
| I didn't know they did that, but surely that counts as farming?

Or predation?

Yes, possibly.

Or even to prevent the spread of the parasite. I agree that none of the
sources cited are conclusive.

Peter