In the wake of hurricane Harvey, you may have heard rumors of floating fire ant rafts in the flood waters. Well, it’s not a rumor at all. The ability to bind together and form rafts to combat flooding is one of the adaptations that make the red imported fire ant such a resilient invasive pest.
Red imported fire ants are native to Central and South America, and were only introduced to the United States in the early 1940’s. Since their arrival, they have spread to 13 states and locations all around the world. They are considered one of the worst invasive species in the world and are a major threat to other wildlife. They also cause billions of dollars in economic damage per year.
These are the broader effects, but most Texans know them for their aggressive behavior and painful sting. Whereas most ants will only bite, or bite and then spray formic acid, fire ants bite in order to penetrate the area with their stinger and inject venom. Over 14 million people are stung by fire ants annually. Most people who are stung will feel an intense burning in the area followed by swelling and fluid filled pustules that usually go away on their own. A very small part of the population can experience anaphylaxis, which is of course, extremely dangerous and life-threatening.
As an entomologist, I appreciate how amazing it is for these social insects to deal with flooding by connecting themselves, with their queen in the center, safe from drowning, as well as their brood which is typically at the top of the “raft”. But, as cool as it is, these floating colonies should be regarded as very dangerous. Unlike swarming honeybees, which are very docile since they don’t have a nest to defend, these fire ants are even more aggressive than normal. They are very vulnerable out of their nest and they will swarm and sting anything that gets to close to them or touches them. If you see one of these ant rafts, keep a very good distance between you and them. Once the raft gets to higher ground, they will move along and search for a place to construct a new nest. In the lab, these rafts have been able to survive on water for up to 12 days, so this is a threat that can be around for quite some time.
While we haven’t exactly constructed rafts out of our bodies here in Houston, I’ve never been so proud to be a Houstonian! I’ve seen teamwork that rivals that of these social insect colonies. Without being told to, or even thinking about it, Houstonians have gotten up to help each other in any and every way they can think of and I think that will be the biggest story out of all of this for years to come! Stay strong Houston!