Scientists accidentally hatch beetles with three functional eyes in a bizarre gene experiment

Unless you’re a particular fan of the beetle, most of us can agree the insects are already pretty gross.

That hasn’t stopped biologists from making the creatures even even more toe-curling, though, by growing a functional third eye in the middle of a beetle’s forehead. If, like us, you’re asking why, it appears it was done by accident.

The scientists from Indiana State University found the accidental third eye growing on the beetle’s forehead in a previous experiment conducted last year. They were trying to establish how the scarab beetle’s various genes determine how the head is organised, structured and how it grows.

 After editing the beetle’s genetic makeup, which involved turning off the gene partly responsible for the development of a beetle’s eyes, the team found that the insects hatched with a third eye on their foreheads.

Now, the same team has followed up on its previous study by further investigating that mysterious third eye and, it turns out, the extra organ has a complex structure that even connects to the beetle’s nervous system.

In fact, the experiment, published in the journal Proceedings of the National Academy of Sciences, reveals that the eye wasn’t simply a fancy decorative piece, it actually worked.

To determine this, the scientists destroyed the cells of the beetles’ regular eyes when they were just larvae before shining a light into the third eye. The beetles would eventually turn their head or lower their eye. As the beetles reacted to the visual input, it showed the structures in the eye had formed with the beetle’s central nervous system.

“This study experimentally disrupts the function of a single major gene. And in response to this disruption, the remainder of hed development reorganises itself to produce a highly complex trait in a new place: a compound eye in the middle of the head,” explained Armin Moczek in a press statement.

This isn’t the first instance of weird growths and extra body parts being developed on animals. Last year, scientists grew a human ear onto the back of a rat. And while this experiment is weird, it is the first ever example of a fully-functioning eye that’s grown on an insect and it opens doors to complex research into how the development of eyes works.