The image you are seeing is the result of a specialized phorid fly laying its egg in the head of a fire ant, which eventually kills its host. This video from Discovery News was posted in 2008, and chronicles one entomologists efforts to combat invasive fire ant populations that originate in Brazil and are spreading throughout the Southern United States. Sanford Porter, is a Research Entomologist for the USDA's Agricultural Research Service in Gainesville, FL.

For some background on Sanford Porter's research see his page on the USDA website. Some details of his research are listed here.

"In 1996, he spent seven months on an ARS fellowship in Brazil studying these flies and developing ways to rear them in the laboratory.

As a result of these studies, he received approval for field release for the first species of decapitating fly Pseudacteon tricuspis in the summer of 1997. These flies have been released at more than 100 sites in 12 states with the help of USDA-APHIS and associates across the Southeast. By the fall of 2008, this fire ant biocontrol agent was estimated to occupy more than 270,000 square miles or about 50% of the fire ant range in the United States.

A second species of decapitating fly, Pseudacteon curvatus, was released in the United States beginning in 2000. This species has been released at more than 60 sites in 11 states and estimated to occupy almost 320,000 square miles or about 60% of the fire ant range. The establishment of a third species, Pseudacteon litoralis, has recently been confirmed in Alabama. A fourth species, Pseudateon obtusus is well established around Gainesville, FL and several sites in Texas. A fifth species, Pseudacteon cultellatus, is being reared and evaluated in quarantine for possible release."

If you have more questions about this battle, we found a very comprehensive page of FAQ's from Larry Gilbert, Director Brackenridge Field Laboratory at The University of Texas at Austin Below is a brief overview of the phorid fly species that parasitize the ants.

"There are over 20,000 species of phorid flies. Most phorid flies are scavengers and some utilize corpses and are useful in forensics (the so-called coffin flies). Phorids that show up in houses typically breed in the sludge in sink drains but could be coming up from animal remains under the house (e.g. dead rats). Phorids that parasitize ants are a highly specialized minority that do nothing except attack and consume ants. The vast majority of people will never knowingly see one of these inconspicuous creatures."

There are also terrific images on http://www.usda-sabcl.org/projects/IFA.htm