Fire Ants Natural Enemy, The Phorid Fly, Has Come To Texas [VIDEO]

We all know how nasty Fire Ants can be.  But, what you may not know is that they are not natural to our area.  The first ants came to the United Sates in the 1930’s through the port of Mobile, Alabama; probably in soil used for ships’ ballasts  and have been spreading ever since.

Red imported fire ants are a very aggressive, efficient competitor ant species to the native variety.  According to a study at Texas A&M University, fire ants cost the economy of Texas over $1 billion per year, while the overall cost to the US economy may amount to $6-8 billion. 

Since the 1950’s in Texas, the ant has been spreading north, west and south. They now infest more than the eastern two-thirds of the state, and some urban areas in western Texas. One of the reasons the ants have thrived so well here in their non-native environment is because when they came to the United States their natural predators (predators, parasites and pathogens) did not follow them here.  The bad news is that the ants are probably here to stay.  The good news is that there have been biological methods deployed to control them. 

One such enemy is the Phorid Fly.  The term phorid fly is used for any of the flies belonging to the family Phoridae.  Certain species of flies belonging to the genus Pseudacteon are known to attack fire ants and kill them as part of their reproductive cycle.  The fly lays its eggs in the head of the ant and when the larvae matures the head of the fire ant pops off releasing a new fly into the world.  There are a total of 25+ of these type of flies that prey on the ants.  We contacted Dr. Rob Plowes, the operations, research & teaching coordinator for the Brackenridge Field Laboratory, to see what progress had been made concerning the Phorid Fly.  We wanted to know if any of the species of fly were present in Austin County or One of the surrounding counties, how many species were released in Texas, and how were they handling Texas climate?  He responded:

The 3 fly species that were released in Brazoria County have spread from northward and are expected to be present in Austin County by now.  

Of the 25+ species of phorids that attack Red Imported Fire Ants (RIFA), we have released 4 in Texas.  Pseudacteon tricuspis was the first released but its populations were reduced through competition with the next fly to be introduced (P. curvatus).  We see high abundances of P.curvatus during the Spring and Fall.  Both of these species attack fire ant at nest or mound disturbances.  Of potentially greater importance is the 3rd species released, P. obtusus, which attacks larger worker ants on foraging trails. We are particularly interested in flies that can shut down foraging activities since these species could reduce the colony growth rates. We are actively working on the importation and release of another species that would attack the more abundant smaller ant workers on foraging trails.  Finally we have also released at 3 sites P. nocens, which is active in the cool of the day when other flies have shut down.

We emphasize that the flies will add pressure on RIFA to help control colony sizes and population growth, but the flies themselves are simply colony parasites and so are not expected to eliminate or eradicate their ant hosts, but should help to make them more manageable.  In complementary work we are also studying several fire ant pathogens (microbes and viruses) and conducting surveys in Argentina to look for additional natural enemies.  Overall, this is a long term program and we are fortunate to have the support of Texas landowners for access to property and funding. 

Our research team is also studying the tawny crazy ant (Nylanderia fulva) and how it is displacing fire ants by detoxifying fire ant venom. We have just discovered the first pathogens in tawny crazy ants, and are doing field research to look at their spread and impacts.  Tawny crazy ants are a real threat to Austin County since there are populations in several nearby counties.  It appears that they are being spread by human transport such as plant nursery products, agricultural packaging, and even in RV’s.

Whatever the outcome, Fire Ants are here to stay so it’s best if you learn as much as you can to be able to combat and control this destructive pest.  If you would like to learn more about Fire Ants, you can go to the Texas A&M Agrilife Website, HERE.  If you would like to learn more about the Fire Ant Program being conducted by the University of Texas to introduce the Phorid Fly, you can click HERE.

Below are two videos showing how the Phorid Fly attacks Fire Ants, killing them as part of their reproductive cycle: