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.
These are termites and carpenter ants, and theyâre about to swarm. Swarmers are what the professionals call the winged termites and carpenter ants. Theyâre mostly females, and their sole purpose is to reproduce with males and establish new colonies. To you, carpenter ants and termites swarmers may look the same â theyâre black with wings.