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.
Like ants and some bees and wasps, which are in a separate order, Hymenoptera, termites divide labour among castes that consist of sterile male and female workers and soldiers. All termite colonies have fertile males called kings and one or more fertile females called queens.Termites mostly feed on dead plant material and cellulose, generally in the form of wood, leaf litter, soil, or animal dung.he diversity of termite species is low in North America and Europe (10 species known in Europe and 50 in North America), but the diversity of termites in South America is high, with over 400 species known.