The number of serious foreign pests that are finding their way into this country has been rising in recent decades. It’s not just happening here—due to increased globalization, this is happening all around the world. Although the spread of pests has been increasing, an interesting recent study has been able to document the spread of one serious pest 500 years ago, when sailing ships spread tropical fire ants throughout warmer areas of the world.

Tropical fire ants, not to be confused with red imported fire ants, are native to our Southeastern states, as well as Mexico and down into South America. Spanish sailing ships during this time were establishing new trading routes. These routes carried goods from Mexico (Acapulco), to the Philippines, and from there to Taiwan, and other areas of Asia and the world.

By studying genetic diversity in tropical fire ants at these locations, it can be seen that these ants originated from Southwestern Mexico, where Acapulco is, and then were carried to the countries where the ships went. The habit of the ships was to fill their ballast with soil, then dump the soil when they reached their destination, and replace it with cargo. By doing this, they were unknowingly moving many pests to new areas of the world.