FIGURE 1.

Enucleation and exposure to a black background dramatically increase perioptic melanophore numbers. (A) The position and size of the counting domains (dashed lines) within each region of analysis is indicated: dorsal midline, perioptic area, flank, and tail (see methods for details). In comparison to controls, melanophore number was unchanged along the dorsal midline, increased dramatically in the perioptic zone, and minimally increased in the flank and tail of enucleated larvae. (dorsal midline: $\overline{X}$ _cnt = 1.00 ± 0.02, $\overline{X}$ _enuc = 1.03 ± 0.02; perioptic: $\overline{X}$ _cnt = 1.00 ± 0.11; $\overline{X}$ _enuc = 3.98 ±0.28; flank: $\overline{X}$ _cnt = 1.00 ± 0.04; $\overline{X}$ _enuc = 1.20 ± 0.06; tail: $\overline{X}$ _cnt = 1.00 ± 0.04, $\overline{X}$ _enuc = 1.29 ± 0.06; mean ± s.e.m.; n _cnt = 32, n _enuc = 33; N = 4) (B) The impact of 24 h exposure to a black background (BB) on perioptic melanophore number was examined. When compared to white background (WB)-exposed controls, BB-treated larvae showed a significant increase in perioptic melanophores, although enucleated larvae displayed an even greater increase in these cells. ( $\overline{X}$ _cnt/WB = 1.00 ± 0.13, $\overline{X}$ _BB = 2.34 ± 0.20, $\overline{X}$ _enuc = 3.56 ± 0.32; F _3,96 = 30.42, p < 0.0001, one-way ANOVA) n. s., not significant, *p < 0.05, **p < 0.001, ***p < 0.0001, unpaired two-tailed Student’s t-test (A), and Tukey’s (B).