The common names for species vary from place to place, and often refer to more than one species.

For example, in America: the name 'Tobacco Budworm' usually refers to Heliothis viridescens. However, this species does not occur in Australia, and the common pest on Tobacco here is Helicoverpa armigera, so this is commonly called the 'Tobacco Budworm'.

Scientific names were invented to dispel such ambiguities: Each distinct species gets only one scientific name, and that name is used over the whole world.

They are sometimes difficult to pronounce because to avoid favouritism for any particular country, these names are derived from the ancient Greek and Latin languages.