How many butterflies and moths are there in the world? In specific parts of the world?
Worldwide, around 150,000 species of Lepidoptera have been described, making this order the second richest group of insects (only beetles are more species-rich). Of this number, just under 20,000 are butterflies, which means the other 130,000+ are moths. The actual number of Lepidoptera in the world is considerably larger (estimates run anywhere from 250,000 to 400,000), as there are many species which have yet to be described, particularly in the tropical regions of the world. Even in Europe and the United States, where the fauna is considered to be pretty well known, there are still many new species of moths (and even a few butterflies) that are described each year. Many of these are quite small and dull, but even large and colorful species remain to be (and are) described each year, particularly in the tropics.
