If you’re an invading, meat-eating Argentinian ant, and you run out of prey, there’s only one thing to do if you want to keep invading—become a vegetarian. And that’s just what the carnivorous Argentinian ants that have invaded California did.  They switched and began to eat vegetable matter.  No, these two-millimeter long critters didn’t develop moral qualms about eating meat and they aren’t trying to save the planet.  They just ran out of their first choice, native ants.  Researchers writing in the Proceedings of the National Academy of Sciences say that these ants gobbled up the native ants, which can be ten times their size. The newcomers then had no choice but to carbo-load, switching over to such sweet treats as honeydew nectar produced by aphids. The ants, which are believed to have arrived in California on ships carrying coffee and sugar from Argentina in the 1890s, have caused problems for big creatures as well. The coastal horned lizard, which dined on domestic ants, has declined in numbers by about half recently.  Apparently because the lizard doesn’t particularly care for Argentinian food.

—Steve Mirsky, with reporting by Harvey Black