 He also recognized nectar theft by certain insects.During his lifetime, his work was somewhat neglected, not only because it seemed to a lot of his contemporaries as obscene that flowers had something to do with sexual functions, but also because the immanent importance of his findings on the aspects of selection and evolution was not recognized.One contemporary A. W. Henschel in Breslau (1820) wrote that Sprengel's idea gave the impression of a fairy tale to entertain a schoolboy.