Move over, cuckoo. The new master designer of impostor eggs is a genus of fungus called Athelia, some species of which trick termites into nurturing their young. Sclerotia, or “termite balls,” are tough, filamentous orbs that can sprout into fungal colonies when dropped into piles of termite excreta, where competition for resources is lacking. As they do for any ball of similar diameter and scent as their eggs, termites assiduously smear fungal balls with their saliva, a moisturizer and antibiotic. For their part, the fungal spheres neither benefit nor harm eggs tended in petri dishes, reports Okayama University entomologist Kenji Matsuura in a Proceedings of the Royal Society B paper published online January 24. He concludes that the fungus cuckolds termites for its sole gain in this unusual example of egg mimicry.