when native ladybugs munched on harlequin eggs, the insects ended up dead within a couple of weeks. In an attempt to find out why, researchers injected the harlequin's hemolymph (the insect equivalent of blood) into the natives and found that it was lethal. Suspicion fell on a specific chemical compound in the hemolymph called harmonine (named after the genus name, Harmonia). But the new paper does the obvious next step and rules this idea out. They synthesized harmonine, injected it into a native species, and found it had no effect. Going back to the drawing board, they looked more carefully at the invaders' hemolymph. When they did, they noticed it was full of spores from a fungus. These turned out to be from a microsporidia related to Nosomia, a fungus that has been implicated as one of the contributors to bee colony collapse.