3.5. Development of dark pigmentation
About 120 crosses were used to study the development of dark pigmentation in hatched-out larvae. No dark pigmentation was observed in larvae or juveniles, progeny of parents with either red or Kohaku phenotypes (33 crosses). Progeny of parents with the black Bekko pattern were light colored at hatching but a fraction of them developed dark pigmentation starting from about 14-day post-hatching (26 crosses). Some of the transparent parents yielded progeny that developed dark pigmentation similarly to progeny of a Bekko parent (9 crosses). In crosses where บtsuri parents were used, dark pigmentation was detected already in a portion of the hatched-out larvae (57 crosses). The average proportion of dark-pigmented larvae in 30 crosses among บtsuri parents was 24.5%, ranging from 1% to 54.7%. In 13 crosses between บtsuri and Bekko parents, the average of pigmented hatched-out larvae was 10.9%, ranging from 0% to 49.8%. In 14 crosses where one parent was บtsuri and the other had no black color (excluding transparent parents), the average proportion of pigmentation in larvae was 15.3%, ranging from 0% to 40.9%.