noun
adult and larval stages
Technical term in entomology referring collectively to both adult and larval forms, often used in contexts like pest control or life cycle descriptions.
この殺虫剤は成幼虫の両方に効果がある。
This insecticide is effective against both adult and larval stages.
成幼虫の形態の違いを観察した。
We observed the morphological differences between the adult and larval stages.
幼虫 refers only to the larval stage, whereas 成幼虫 includes the adult stage as well.
Compound of 成 (sei, 'adult') + 幼虫 (yōchū, 'larva'), literally 'adult-larva'. The exact historical derivation is uncertain, but the term is used in modern technical contexts.