Kurt Johnson and Steve Coates, Nabokov's Blues: The Scientific Odyssey of a Literary Genius
(Cambridge: Zoland Books, 1999), p. 23:
A few years after it was published, Alexander Klots wrote in his widely read Field Guide to the Butterflies of North America that "the recent work of Nabokov has entirely rearranged the classification of this genus." This notice meant much to the writer. Alfred Appel, Jr., reported in his Annotated Lolita that, when he was visiting Nabokov in 1966, the author took a copy of Klots from the shelf, pointed to this quotation, and said: "That's real fame. That means more than anything a literary critic could say."
Op. cit., pp. 43-44:
"Sugaring" for moths that is, setting out pungent bait to attract them, which Fyodor mentions in the previously quoted passage of The Gift was one of Nabokov's passionate lepidopterological pastimes; as unlikely a picture as the possibility may have presented, he once tried to interest his friend Edmund Wilson in having a go. "Try, Bunny," he wrote. "It is the noblest sport in the world."