Thanks to a bit of genetic sleuthing, researchers now know the invasion history of the tropical fire ant (Solenopsis geminata), the first ant species known to travel the globe by sea.
Their study, reported in the journal, Molecular Ecology, reveals that 16th century Spanish galleons shuttled tropical fire ants from Acapulco, Mexico, across the Pacific to the Philippines, and from there to other parts of the world. Today, the ant species is found in virtually all tropical regions, including in Africa, the Americas, Australia, India and Southeast Asia. (See map.)
“A lot of these ships, particularly if they were going somewhere to pick up commerce, would fill their ballast with soil and then they would dump the soil out in a new port and replace it with cargo,” said University of Illinois entomology professor and animal biology department head Andrew Suarez, an author on the study. “They were unknowingly moving huge numbers of organisms in the ballast soil.”
Photo by Julie McMahon