The Short Version
The underlying phenomenon is real but far narrower than the claim suggests. Controlled experiments confirm that at least two moth species (Manduca sexta and Grapholita molesta) retain specific aversive odor memories from their caterpillar stage into adulthood. However, the claim implies this is a general feature across moths and butterflies broadly, when in fact no butterfly species has been directly tested, the evidence covers only simple olfactory aversions, and Drosophila research shows complete dismantling of larval memory circuits — demonstrating the phenomenon is not universal among insects with complete metamorphosis.