Nick Maclaren wrote or quoted:
In article , Tim Tyler wrote:

Yes, I know perfectly well that the phenomenon occurs in the tropics,
and occasionally in the temperate zones. Even there, I doubt that
"ants are the aphids' friends", because it is probably that there
is more ant predation on aphids than ant protection of them. [...]

AFAICS, that doesn't seem to make sense :-(

Are you serious? Why on earth do you imagine that this particular
ecological association is constant over the whole earth, when no
other one is?

What didn't make sense was the idea that - because orgainisms of
one species eat organisms from another one, the two species are
not in a mutually beneficial symbiotic relationship.

Humans eat lettuces. However humans and lettuces are in a
mutually beneficial symbiotic relationship. The lettuce evolves
to be better and tastier food - since *despite* the fact that
tasty lettuces get eaten, their equally tasty sisters get
deliberately cultivated to provide seed for the next season.

IMO, the ants are *farming* the aphids - in similar ways all over the
world.

Well, you are simply wrong. See any respectable book on entomology.
Michael Chinery "Insects", for example.

What are you claiming here? That there are differences in the ways that
ants farm aphids in different locations? Just because there are
similarities, that doesn't exculde the possibility of there also
being differences. I stand by my statement.

Just because the ants eat the aphids, that doesn't mean the aphids are
/not/ being farmed. You might just as well argue that humans are not
farming pigs because people have been observed to eat bacon.

No, it doesn't. But, as far as every reference that I have seen has
said, 'farming' ants are either absent from the UK or EXTREMELY rare,
and even ones that actively 'herd' aphids are not common.

You've presented no evidence to that effect, that I've seen.

The size of the UK makes it harder to find research on the ant-aphid
symbiosis which is demonstrably applicable.

Would you like to explain that? We have one of the largest and most
effective biological research communities in the world, an ecology
that supports God knows how many ants (but of only a few species),
and hundreds of species of aphids, many of economic importance
(thus meaning that a LOT of research has been done on them).

UK is a small country, most research on ants is performed elsewhere.

For example, one of the main bibles on ant behaviour is Wilson's
"The Ants" - http://www.the-scientist.com/1991/05/27/18/6

Wilson is from America - as is most of the research on ants I see.

Here's a UK paper showing that the ants are defending the aphids:

``Soldiers effectively defend aphid colonies against predators in the field''

- http://calorierestriction.org/pmid/?n=9514674

At LAST! All right, that is evidence. More for my point than yours,
but it does include some evidence that at least one ant does protect
at least one aphid in the UK.

Of course, the family of aphids is a minor one in the UK and is not
the family that causes 95% of trouble to farmers and gardeners, and
the abstract says:

These observations provide the first demonstration that soldiers
are effective in defence against natural levels of predation under
field conditions.

Given the relative importance of the families, how much research do
you think will have found no evidence for this effect?

Research with negative findings rarely gets published.

Maybe that is why you have failed to cite anything on the subject.

...and here's a UK paper showing aphids produced more soldiers when ants
were not in attendance - which strongly suggests the ants were protecting
the aphids:

``Ant tending influences soldier production in a social aphid''

- http://calorierestriction.org/pmid/?n=11052537

I wasn't aware that there was a significant amount of either ginger
or storax either farmed or naturalised in the UK. The fact that the
authors are British doesn't mean that the ants are.

OK, fair enough. Try these:

UK Organic association factsheets:

``Some ants ‘farm’ aphids for the honeydew that they produce. This means
that they protect them from predators and move the pests around a plant
to new ‘pastures’. If a tree is badly infested with ants and aphids, a
band of insect glue round the trunk stops the ants climbing up the
tree. Without protection, aphid numbers will decline as they are
exposed to more parasites and predators.''

- http://www.hdra.org.uk/factsheets/pc10.htm

``Ants have learnt to ‘farm’ these creatures, milking them for a fresh
honeydew drink. Like all good farmers, ants look after their livestock,
protecting them from predators and moving them to new feeding grounds.
This can spread both the pests, and the diseases they carry.''

- http://www.hdra.org.uk/factsheets/pc1.htm

The Royal Horticultural Society - on ants and aphids:

``Ants can protect aphids from attack by ladybirds and other predators in
order to secure their supply of honeydew. Increased numbers of aphids
may result in more damage to plants.''

- http://www.rhs.org.uk/advice/profiles0701/ants.asp

A page about wood ants in Scotland:

``Wood ant tracks are not only on the ground, but are three dimensional,
leading up trees into the canopy above. The ants not only hunt in the
trees, they are known to farm as well. Wood ants have a symbiotic
relationship with aphids (for example Symydobius oblongus). The aphids
are `milked' by the ants who gently stroke them to get them to release
droplets of honeydew, a food that is rich in sugars, acids, salts and
vitamins. To the aphids this is their waste product as they have to suck
a lot of tree sap to get the protein they require. In return for the
honeydew the ants protect their precious sugar source from predators and
competing sap sucking insects.''

- http://www.treesforlife.org.uk/tfl.woodants.html

How I interpret what I see in my garden is ants farming aphids, by
protecting them, raising them, carrying them up to the tops of plants,
and using them as a technological tool to attack the plants, and steal
their juices - both by sucking the honeydew, and by eating the
resulting plump and juicy aphids.

I know you do. And I am pointing out that your interpretation is
prejudice, because you are using your observations to justify your
beliefs and not to check up on them. The evidence is all against
your interpretation being correct.

All *what* evidence?

All the evidence I've seen supports the idea that ants and aphids
tend to form mutually beneficial symbiotic relationships.

I've witnessed phenomena which I can only explain in terms of ant
protection of aphids:

For example last year my bronze fennel was attacked in the autumn by
aphids at ground level. The strange thing was, that the aphids were all
protected by a 4cm high wall of dirt, close up against the fennel stem.
I regularly knocked this off with a stick - and it was regularly rebuilt.
The plant was about four feet from two ants nests. The only conclusion I
regard as plausible is that the ants were responsible for building the
protective wall around the aphid infestation.

Your claim - that ants in the UK don't look after aphids - is the
one that seems to lack any supporting evidence.

I fully expect the ant-aphid symbiosis to be global in extent and ancient
in origin.

Doubtless. The former is known to be not the case, however. See
above.

....where nothing to the contrary is presented - AFAICS.
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