Nabokov's lepidoptery long posed a question: Was he an amateur or a professional entomologist? Today, it has been amply demonstrated that he was a professional. Kurt Johnson says, "For Nabokov, as with many, fascination with the big picture books of butterflies as a young child grew to concerted collecting as a youngster. As with many scientists, these impressions of youth become a driving life force."3 Nabokov started collecting butterflies in 1906, at age seven, and never ceased; he published his first book of poems ten years later, at age seventeen; his first research paper on butterflies, at age twenty; and his first novel, Mashenka [Mary], at age twenty-six. To quote Dieter Zimmer, "For Nabokov lepidoptery was not a mere hobby. It was a lifelong passionate interest that began when he just turned seven, eight years before he began to compose his first poems, with his first Old World Swallowtail in Vyra."4
Fet, Victor. “Notes on Nabokov's childhood entomology.” Fine Lines: Nabokov's Scientific Art, edited by Stephen H. Blackwell and Kurt Johnson, Yale UP, 2016, pp. 216-224.