Digging behavior of D. melanogaster larvae increases as larval develop
ment proceeds. Diallel crosses were made to analyze genetically diggin
g behavior at 72 and 108 h of larval age. Additive and dominance varia
tion was found, dominance being principally to dig. Dominance to dig i
s higher at 108 than 72 h of development; additivity does not substant
ially change between these two larval ages. At 72 h of larval age, dep
ending on the cross, I found (i) dominance to dig, (ii) dominance to n
ondig, (iii) overdominance to dig, and (iv) no dominance to dig. At 10
8 h of larval development I detected (i) dominance to dig and (ii) ove
rdominance to dig. Thus, diversity of response in the F, was greater a
t 72 than 108 h of larval development. These age-related changes in la
rval digging behavior of D. melanogaster seem to reflect epigenetic ch
anges in the patterns of gene expressions.