The BVD stands for Back Vertex Distance, this is a measurement that is included on any prescription where the sphere or cylinder powers are higher than + or - 5.00D and to a lesser extent some prescriptions where it is less than this power.
Winged Drone | Alate | Male Ant. Drones are the only male ants in a colony. They are born from un-fertilized eggs. Drones are not like typical ants. They donât do any work in their nests, and they look more like wasps than ants. They are reproductive winged ants and so are alates.
The sexuals or reproductives in ants are called alates. Females are called queens or gynes, while males are usually just called males. In the case of male alates, their only function is to reproduce.They usually stay in their home colony until they are fully developed and then they fly away to mate.emales are called queens or gynes, while males are usually just called males. In the case of male alates, their only function is to reproduce. They usually stay in their home colony until they are fully developed and then they fly away to mate.