The red imported fire ant, Solenopsis invicta, is a highly invasive species known for its painful sting and extensive mound building. Fire ants do indeed fly, but this behavior is limited exclusively to specific reproductive individuals during a synchronized period of colony expansion. This phenomenon is a necessary part of their life cycle that ensures the creation of new colonies across a wide range.
Which Fire Ants Have Wings
Only certain members of a fire ant colony are physically equipped for flight, which are the winged reproductives known as alates. These alates are virgin queens and males that are produced by a mature colony when conditions are right for reproduction. The vast majority of the colony—the sterile female worker ants that build the mounds and forage for food—remain wingless throughout their entire lives.
The alates are larger than the workers and are destined to leave the nest to mate. A common confusion arises when these winged ants appear, as they are often mistaken for flying termites, which also swarm. Distinguishing between a fire ant alate and a termite swarmer requires looking at three distinct physical characteristics.
A flying fire ant possesses a noticeably pinched waist, which is a narrow connection between the thorax and the abdomen, giving the ant its segmented appearance. Their antennae are “elbowed,” meaning they are distinctly bent at a 90-degree angle. Furthermore, the fire ant alate has two pairs of wings that are unequal in size, with the forewings being significantly larger than the hindwings.
A termite swarmer, in contrast, has a thick, straight waist, giving its body a more uniform, cylindrical shape. Termite antennae are straight and appear beaded, not bent. Termites have four wings that are all nearly equal in size and length.
The Purpose of Mating Swarms
The act of flying is a single event called the nuptial flight. This synchronized mass emergence of alates is the only opportunity for mating and the dispersal of new queens. The purpose of this flight is to prevent inbreeding and ensure genetic diversity by mixing with reproductives from distant colonies.
These mating swarms are initiated by specific environmental cues. Flights most often take place in the late morning or afternoon, immediately following a recent rainfall that has saturated the ground. High humidity and surface temperatures between 21 and 33 degrees Celsius provide the ideal conditions for the ants to take flight.
Once the workers open exit holes in the mound, hundreds to thousands of alates emerge and ascend into the air. The males typically fly first, forming dense aerial aggregations, which the virgin queens then fly into to find a mate. Mating occurs high above the ground, often reaching altitudes of 250 meters or more, facilitating long-distance dispersal.
Life Cycle After the Flight
The consequences of the nuptial flight are quick and different for the two sexes. After mating occurs in the air, the male fire ants die shortly after descending. The newly inseminated female, now a potential queen, descends rapidly to the ground to begin establishing a new colony.
Upon landing, the queen sheds her wings, a process called dealation, which is a definitive sign she is transitioning from a winged reproductive to a wingless founder. She then searches for a suitable, protected spot, often a small crevice or under an object, and tunnels into the soil to create a small chamber. This initial chamber serves as a protected nursery where she seals herself in to begin laying her first clutch of eggs, typically a small group of about a dozen.
The new queen cares for and feeds this first brood herself, relying on her stored fat reserves and the energy from her shed wing muscles. Once these first larvae develop into worker ants, they take over the responsibilities of foraging, nest maintenance, and caring for subsequent broods. This shift allows the queen to dedicate her focus to reproduction, enabling her to lay up to 800 to 1,500 eggs per day, leading to the rapid establishment of a new fire ant mound.