Fig. 9.
A, Effects of a 12 hr dark shift at different ages after emergence. Dark-rearing during the first 12 hr (B) leaves the lamina as small as that found after 4 d in darkness (G) but similar dark shifts at later ages exert smaller effects (groupsC–E). Dark-rearing during the last 12 hr (F), i.e., during the subjective night of the animals, reduces size even less (nA = 11,nB = 10, nC = 11,nD = 10, nE = 10,nF = 10, nG = 11). B, A reduction in volume compared with LL flies (n = 14) could represent a more natural response, because flies kept in an LD light regime (n = 26) have a lamina size that is intermediate between LL and DD flies (n = 22).