Scorpion’s sting evolved from insects’ defensive proteins

The proteins that prevent viral, bacterial or fungal infections in insects are similar in structure to stinging proteins in scorpions. Removing a tiny loop on one defensive insect protein changed the molecule’s function from fighting against microbes to having the ability to paralyze prey, researchers report January 14 in Molecular Biology and Evolution.

The experiment is the first to show how insect proteins could have evolved into the more damaging toxins seen in scorpions.