The western honey bee or European honey bee (Apis mellifera) is the most common of the ~40 species of honey bee worldwide. The genus name Apis is Latin for "bee", and mellifera means "honey-bearing", referring to the species' tendency to produce a large quantity of honey for storage over the winter. Western honey bees are an important model organism in scientific studies, particularly in the fields of social evolution, learning and memory; they are also used in studies of pesticide toxicity, to assess non-target impacts of commercial pesticides.