Parasitic ‘Horror Wasp’ Found Growing Inside Living Flies Discovered In The US

Scientists in Mississippi have discovered a new parasitoid wasp species that matures inside adult fruit flies, eventually bursting out, much like scenes from the ‘Alien’ films. This newly identified wasp, named ‘Syntretus perlmani’, is unique as it infects adult fruit flies, unlike related wasp species that target larvae or pupae.

The research, conducted by Logan Moore during his doctoral studies at Mississippi State University, was published in ‘Nature’ on September 11. The wasp species was discovered by chance while Moore and his team were collecting fruit flies in their backyards. Initially searching for parasitic worms, they found a peculiar wasp larva inside a fly in March 2023, leading them to further investigations. The discovery was later confirmed through DNA analysis and rearing the wasps in a lab.

In an interview with ‘Live Science’, Moore described how female ‘S. perlmani’ wasps use a specialized organ called an ovipositor to inject eggs into the abdomen of adult fruit flies. Over the course of 18 days, the larvae develop inside the host, eventually emerging and killing the fly. Moore explained, “It will effectively emerge out of the side of the fly, and just to add an additional layer of horror, the fly will normally remain alive for several hours after that.”

What makes ‘S. perlmani’ extraordinary is its ability to infect adult flies rather than their more defenseless juvenile stages. Most parasitoid wasps attack larvae or pupae, which are easier targets. Moore remarked, “This is all around us, infecting one of the most well-studied animals on the planet… It just leaves you wondering what else is out there on our doormat right now.”

The team found evidence of the wasp across several states in the eastern U.S., including Mississippi, Alabama, and North Carolina, as well as its presence in ‘Drosophila melanogaster’, a widely researched fruit fly species.