Simplify the following text for a Grade 6 native English-speaking person.
Original: As this is the only stage during which the insect is sexually mature and , if it is a winged species , has functional wings , the imago is often referred to as the adult stage .
Simplified: This is the only stage in which the insect is sexually mature and , if it is a winged species , has functional wings . The imago is often referred to as the adult stage .