Table 1.

Summary statistics from Welch's t tests comparing the Michelson contrast between the radiance of Tripterygion delaisi’s irides to that of common substrates under four environmental light conditions. Tests were only performed for substrates with at least 10 replicate measurements. We controlled for false discovery rates due to multiple comparisons following Benjamini and Yekutieli (Benjamini & Yekutieli, 2001). The algal species covering the substrate are coded as follows: Cl, Chaetomorpha linum; Dl, Dictyota linearis; Hf, Halopteris filicina; Jr, Jania rubens; and Pf, Padina pavonia (see Appendix S1)

Depth (m)	Degree of exposure	Substrate	t	df	p
5	Exposed	Cl	6.32	14	<.001
		Hf	5.89	25	<.001
		Pp	1.56	21	.14
		Rock	7.41	10	<.001
5	Shaded	Cl	3.23	10	<.001
		Hf	12.41	36	<.001
		Sponge	23.98	11	<.001
20	Exposed	Hf	‐0.20	10	.58
20	Shaded	Dl	6.53	9	<.001
		Hf	7.55	25	<.001