Giraud, T., Pederson, J.S.and Keller, L. evolution of
supercolonies: the argentine ants of southern europe.
Proceceeding of the national academy of sciences, 99,
708-712, (2002).

Summary:

This seems unlikely possible to happen but it has
happened an invading empire has conquered Europe.  a
colony of south american ants, with millions of nests
and billions of individuals, stretches 6,00 kilometers
around the mediterranean and atlantic coasts,
researchers have found.  every ant in this colony treats
other ants as a mating partner.  The nest has barried
its differences throughout the colony to create the
largest cooperative unit ever discovered.  There seems
to be no aggression among the ants.  The empowerment of
the Argentine ant has made it a big problem and they
have become pests to many.

They are a threat to agricultural and native lands.
other incasive ants, such as the fire ants of the
southern united states, cooperate, although not on the
same scale.  the argentine ant has invaded every
continet except antartica, and has reached islands
including Hawaii and New Zealand, by hitchhiking with
hemans.  This seems to be bad news for those people.  in
soth america, ants from nests a few matres apart fight
to the dath. most european ants showed no aggression
towards each other, even when their homes were thousnds
of kilometres apart.  this suspension of hostilities
allowa the nests to crowd together, then the team
speculates.  cooperation becomes a better statergy than
conflictm even though the ants are not related.  ants
use chemical badges to recogmnize nest-mates.  a
scientist speculates that after the ants arrived in
europe in the 1920's they teamed up with unrelated ants
that happened to share a badge in order to achieve
domination. Argentine ants have not quite achieved
european unification however they are making a lot of
people mad and destroying a lot of ground.