Regular readers of The Daily Ant likely already know that ants are very good at most things. From farming to construction to warfare, ants are rivaled perhaps only by humans. So, it is not surprising that along with a diverse array of interesting and intriguing behaviors, ants are also excellent at something we humans find a little less exciting: biological invasions.
In 2000, the Invasive Species Specialist Group (ISSG), in collaboration with the IUCN and others, published a list of the top 100 worst invasive species in the world. On this list, which includes organisms ranging from viruses to fungi to plants, ants are conspicuously prevalent. In fact, ants alone represent a remarkable 5% of the list. These invasive ant species are listed below, with their current known species range according to AntMaps (red = invasive range). All ant images are from Alex Wild.
Argentine Ant (Linepithema humile)
Big-Headed Ant (Pheidole megacephala)
Crazy Ant (Anoplolepis gracilipes)
Little Fire Ant (Wasmannia auropunctata)
Red Imported Fire Ant (Solenopsis invicta)
As can be seen from the above species distributions, invasive ants have found their way into most human-occupied regions in the world. However, it is important to note that these five bad actors represent a mere 0.038% of total ant diversity! Remember to judge each ant species based on its own merits rather than the invasive behavior of a few.