Invasive ants form super-colony  Argentine ants attack a
harvester ant. / photo by Alex Wild * David Holway, an ecologist
and evolutionary biologist at UC San Diego, stands in a field
where he has been studying Argentine ants that have moved into
the site -- which is near a residential neighborhood. / photo by
Nelvin C. Cepeda * U-T  The invaders have overrun homes and
jumped continents, employing tight family networks and singular
group loyalty to achieve domination.  Among a world of
intricately diverse insect species, uniform populations of
Argentine ants have swept the globe, wiping out native ants,
threatening local plants and animals, and creating a nuisance in
kitchens each summer. These creatures appeared in the United
States around the turn of the last century and quickly made
themselves at home.  The Argentine ants that raid pantries in
San Diego County nowadays are closely related to those in
Northern California, Japan, New Zealand and Europe, according to
scientists who have studied international