Answer: lepidopterist.
A lepidopterist is a person who studies butterflies and moths. Vladimir Nabokov was a lepidopterist, and his interest in insects contributed to his fascination with Kafka's The Metamorphosis, in which the protagonist turns into a bug. Nabokov even theorized on what kind of bug Samsa was. His conclusion was that, contrary to popular belief (which often assumes Samsa to be a cockroach), he was a beetle.
