EXPERIMENT   Chrysoperla plorabunda and Chrysoperla johnsoni are two species of lacewings that sing different courtship songs.

 RESULTS   The F1 hybrid offspring sing a song in which the length of the standard repeating unit is similar to that sung by the C. plorabunda parent, but the volley period, (the interval between repeats), is similar to that of the C. johnsoni parent.

 CONCLUSION   The songs sung by C. plorabunda and C. johnsoni are innate, not learned.

Many birds learn their songs from parents or other individuals of the same species.