Solenopsis invicta, or the “red-imported fire ant,” as the species is more commonly known, is the most economically significant invasive ant pest in the United States. These ants are native to South America, but they have been accidentally transported into the US multiple times within infested shipping cargo arriving at US ports along the Gulf Coast. Since the 1930s, RIFAs have been expanding their invasive habitat range throughout many southern states where they have had a negative effect on ecosystems, public health, livestock operations, commercial crops, and residential life.
Red-imported fire ants (RIFA) are well known for establishing hazardous colonies over large areas of land, and it is not uncommon for these ant pests to infest entire neighborhood landscapes and city blocks. Most medically harmful RIFA attacks occur in response to residents unknowingly stepping on nests located in residential yards. Stepping on RIFA nests triggers hundreds or even many thousands of ants to emerge from the ground in order to inflict repeated stings on the offender’s skin. These attacks land thousands of people in the hospital annually in Georgia, and dozens of Americans have been killed in response to RIFA envenomations.
In their native South America, RIFA colonies remain modest in size because their natural predators prevent RIFA population numbers from growing out of control. In the US, however, RIFAs have very few predators to keep their populations from growing to ecologically disastrous proportions. Because of this, RIFA colonies in the US continue growing indefinitely in population size, which allows the aggressive ants to become abundant enough to wipe out native arthropod populations. This results in major ecological upset, as well as the continued expansion of RIFA populations onto urban and suburban landscapes.
According to one recent academic publication, there may be a silver lining to an overabundance of RIFA colonies on suburban and urban landscapes. Disease-spreading ticks are one of the many groups of arthropods that RIFAs prey on to near extinction. The study’s authors suggest that the rate of tick-borne alpha gal syndrome in the southeast has been decreasing because RIFAs have been killing the bloodsuckers before they have a chance to bite residents.
Have you noticed a decrease in tick numbers around your home this year?