Nick Maclaren wrote:

Thanks for the references. I have looked for evidence in many parts
of the country, and never seen it, so my estimate is that it can't be
a universal practice. Black bean aphids and L. niger are universal
in the UK :-)

But, yes, I agree that the last paper is strong evidence for herding.
What NONE of those are is evidence for farming, and one of the papers
you quote says that they saw none, either.

Ants elimitate aphid predators and reduce aphid infections.

``In turn, ants often act as guards and decrease the impact
of predators and parasitoids on the fitness of their hosts
(El-Ziady and Kennedy 1956, Banks 1962, Way 1963, Banks
and Macaulay 1967, Addicott 1979, Pierce and Mead 1981,
Buckley 1987a, b, Vo¨ lkl 1992).''

- http://www.brown.edu/Departments/EEB...00_ecology.pdf

Their effect on aphid fitness is dramatic and positive:

``Ant-tended individuals of M. fuscoviride lived on average 78%
longer, needed 10% less time to mature, gave birth
to offspring at a rate that was 88% higher, and had
an expected number of offspring that was more than five
times higher than that of individuals not tended by ants.''

- http://www.brown.edu/Departments/EEB...00_ecology.pdf

....and they cause the aphids to suck more sap out of plants:

``It must be concluded that the ant-attended aphids produced
the 'extra' radioactivity in the honeydew by increasing the
uptake of radioactive sap from the plants. It follows,
therefore, as Herzig supposed, that the ants directly
stimulated both the excretion and feeding rates of the aphids.''

- http://jeb.biologists.org/cgi/reprint/35/4/703.pdf

Ants consume aphid milk, and consume aphid flesh.

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

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