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. 2009 Apr 8;4(4):e5111. doi: 10.1371/journal.pone.0005111

Figure 1. Effects of stress factors and PSR on colouration.

Figure 1

The theory predicts that colouration remains unchanged in the absence of stress (i: no difference from time i to time i+1), while colouration is reduced in the presence of a stress factor (ii: colour reduction from time i to time i+1). In the presence of a stress factor animals activate the ELHS, thereby decreasing the negative effects of the stress. As a consequence, the colour reduction (ii) between time i and time i+1 will be smaller when the PSR is stronger (iii, iv). If activated ELHS provokes the same effects in the presence and absence of stress factors, as suggested by several studies [30], [42]–[44], activated ELHS may lead to increased colouration (v: colour increase from time i to time i+1).