The University of Arkansas Extensions office in Clark and Hot Spring counties are pitting flies against fire ants in an attempt to mitigate the stinging insect’s population in the southwest of the state.
And while experts believe fire ants have been in the state since the 1950’s, the insect is actually native to South America, and was brought to the United States. accidentally on a ship that docked in Mobile, Alabama, in the 1930s.
Although not a native species, the red fire ant has been able to thrive in the southern United States due to it’s lack of a natural predator. “Our population densities are five to ten times what South America’s are because we don’t have any natural predators here,” said Amy Simpson, University of Arkansas Extension Clark County.
There is one natural predator of the fire ant, and it is known as the phorid fly. It’s why the fly was introduced to the Arkansas fire ant population about a decade ago. And last week, The Universit of Arkansas Extension offices in Clark and Hot Spring counties began introducing two new species of phorid flies to help wage war against two other types of fire ant at DeGray Lake State Park in Bismarck.
They released roughly 700 Pseudacteon obtusus and Pseudacteon cultellatus flies.
The Phorid fly acts as a parasite. The female flies attack the fire ants and lay their eggs in their thorax – the only way the flies reproduce.
“When it [the egg] goes into the pupa process, it moves into the head capsule and it actually releases an enzyme that dissolves some of the connective tissue which makes the head fall off,” said Simpson.
But Simpson said it’s not the decapitation that’s expected to bring down the state’s population of fire ants. Rather, it’s the ants natural fear of the flies that forces them to retreat underground, and reduce the amount of time the ants forage for food.
“So they’re not bringing as much food back to the colony,” said Simpson. “That in turn causes the queen to lay fewer eggs because there’s not enough food to support more eggs.”