Complex social organization with caste formation is best known for social insects and naked mole rats. Ana Garcia-Vedrenne's study presented evidence for trematode parasite social organization involving reproductive “Queens” and defensive “soldiers", all clone members, genetically identical. She examined 14 trematode species that infect the California horn snail, Cerithidea californica. Half of these species appear to have a division of labor involving a soldier caste, while the other half provide information on colony structure when soldiers are lacking.