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.
7) Fire ants. Fire ants are considered to be the most aggressive species of ants in nature as they cause painful sting once provoked. There are about 200 species belonging to the genus Solenopsis. They are also called ad red ants as they exhibit light brownish red color. These insects normally leaves in soil and feed on plant tissues, crickets and on other smaller insects.