Fig. 9. Temperature downshift experiments reveal xanthophore recovery and pattern regulation after Fms activation. (A-C) Examples of fms^174A homozygotes reared at 33°C to the size indicated (upper panels) then shifted to 24°C until an adult pigment pattern had formed (lower panels). (A) Larva shifted during early pigment pattern metamorphosis (6.5 mm SL) recovered xanthophores and a wild-type pattern of adult melanophore stripes (15.9 mm SL, A') after 34 days at 24°C. (B) Larva shifted during middle stages of pigment pattern metamorphosis (8.1 mm SL) recovered xanthophores and normal adult melanophore stripes (17.3 mm SL, B') after 34 days at 24°C. (C) Individual shifted when pigment pattern metamorphosis was essentially completed (12.3 mm SL) has recovered some xanthophores but not a normally organized stripe pattern (14.1 mm SL, C') after 14 days at 24°C. (Insets) Higher magnification views of boxed regions showing xanthophores. (D-I) Individuals reared initially at 33°C through late larval stages can regulate xanthophores and stripes after several weeks to months following shift to 24°C. Shown are sequential images of the same region on a representative fms^174A individual (starting 12 mm SL) at 2 days (D), 10 days (E), 16 days (F), 22 days (G), 27 days (H), and 40 days (I) after temperature downshift. Note increasingly organized and spread melanophores as xanthophores populate the flank. (Upper images) Low magnification showing melanophore distributions. (Lower images) Higher magnification of boxed regions showing recovery of xanthophores (arrow). (J-L) Perturbation of fin patterning when Fms is activated late in development. (J) Normal horizontal stripes form in the caudal fin of fms^174A individuals reared at 24°C. Xanthophore stripes on the fin extend caudally from stripes on the body (arrow). (K) Xanthophores and stripes are absent in the fins of fms^174A individuals reared at 33°C. (L) Xanthophore recovery accompanied by stripe reorientation in fms^174A when Fms is activated only late in development. Scale bars: (A,B) 1 mm, (C) 2 mm, (A'-C') 500 µm, (D-I) 250 µm, (J-L) 1 mm.

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