It's worth noting that data was collected by amateurs in the sense that they're doing this on their spare time but some of them are highly regarded in their field. Quote from http://www.sciencemag.org/news/2017/05/where-have-all-insect...

    Members of the Krefeld society have been observing, 
    recording, and collecting insects from the region—and
    around the world—since 1905. Some of the roughly 50 
    members—including teachers, telecommunication 
    technicians, and a book publisher—have become world 
    experts on their favorite insects. Siegfried Cymorek, 
    for instance, who was active in the society from the 
    1950s through the 1980s, never completed high school. 
    He was drafted into the army as a teenager, and after 
    the war he worked in the wood-protection division at a 
    local chemical plant. But because of his extensive 
    knowledge of wood-boring beetles, the Swiss Federal 
    Institute of Technology in Zurich awarded him an 
    honorary doctorate in 1979. Over the years, members 
    have written more than 2000 publications on insect 
    taxonomy, ecology, and behavior.