Supplementary Information
Supplemental methods: We calculated relative hind limb length by regressing logtransformed limb length on log transformed snout-vent length and then calculating residuals from this regression. To perform power analyses, we calculated the effect sizes for each experimental treatment (competition and predation). Because results were significant for competition experiments, we then solved for the power to detect an equivalent effect size in the predation experiments, had such an effect existed. We corrected for years effects in our study by calculating selection differentials for each island and then saving the residual scores from an analysis of these coefficients versus year.

Table S1. Summary table of data used in this study. Predation treatments are shown for
each island and year of our study. SVL: snout-vent-length, STAM: stamina, REL HIND: relative hindlimb length. Selection differentials (s) and gradients (

) are reported along with associated standard errors, as are values of selection corrected for year (Residual s).
Population densities are reported as the number of lizards per m
2
of vegetated habitat on each island.
Island Year Predation
N
(released/survivors)
Males Females Trait
FLAM 2008
HERON 2008
None
Birds
40/22 159/72 SVL
STAM
0.37 (0.14) 0.29 (.13) 0.14
0.37 (0.14) 0.20 (0.13) 0.05
REL HIND 0.36 (0.14) 0.32 (0.12) 0.29
40/26 160/56 SVL 0.39 (0.23) 0.29 (0.25) 0.16
STAM 0.36 (0.08) 0.25 (0.25) 0.04
REL HIND -0.10 (0.24) -0.11 (0.23) -0.17
FLAM 2009
NMC 2009
Birds
None
81/28 150/85 SVL
STAM
REL HIND
80/28 150/51 SVL
STAM
-0.09 (0.07)
0.02 (0.07)
0.02 (0.08)
0.02 (0.16)
-0.17 (0.16)
-0.11 (0.07) -0.07
0.05 (0.07)
0.03 (0.08)
0.05 (0.16)
0.15
0.08
0.05
-0.17 (0.17) -0.04
REL HIND -0.09 (0.16) -0.05 (0.17) -0.04
MYST 2009 Birds+Snakes 81/16 150/42 SVL -0.20 (0.23) -0.07 (0.26) -0.18
STAM
HERON 2009 Birds+Snakes 81/24 149/50 SVL
-0.29 (0.23) -0.22 (0.25) -0.16
REL HIND -0.25 (0.23) -0.21 (0.23) -0.20
0.17 (0.17) 0.16 (0.17) 0.20
STAM -0.07 (0.18) -0.04 (0.18) 0.06
REL HIND 0.10 (0.17) 0.12 (0.18) 0.16
Natural s (SE)
Selection estimate

(SE)
Density
Residual s ( N /m 2 )
KIDD 2008 150/41 232/74 SVL
STAM
-0.08 (0.08)
0.23 (0.08)
-0.06 (0.12) -0.31
0.26 (0.15) -0.09
REL HIND -0.05 (0.09) -0.06 (0.11) -0.12
0.30
0.18
0.09
0.25
0.20
0.23
0.09

Table S2. Summary of phenotypes measured for male lizards in this study. All abbreviations are as in Table S1 except that HIND refers to raw hind limb length (mm).
Trait means and standard errors are reported prior to and following one round of viability selection.
Before selection
After selection
Island Year Trait
FLAM 2008 SVL
STAM
HIND
HERON 2008 SVL
STAM
HIND
FLAM 2009 SVL
STAM
HIND
NMC 2009 SVL
STAM
HIND
MYST 2009 SVL
STAM
HIND
HERON 2009 SVL
STAM
HIND
KIDD 2008 SVL
STAM
HIND
Mean (SE) Mean (SE)
60.78 (1.24) 63.64 (1.14)
167 (8.79) 187 (10.55)
16.77 (0.33) 17.73 (0.29)
59.29 (1.25) 62.31 (1.39)
153 (6.44) 167 (8.85)
16.66 (0.35) 17.42 (0.48)
56.92 (0.48) 56.51 (0.61)
163 (5.44) 164 (6.46)
15.58 (0.13) 15.49 (0.16)
57.8 (0.44) 57.87 (0.74)
166 (5.91) 158 (8.09)
16.01 (0.13) 15.97 (0.20)
57.53 (0.47) 56.31 (1.09)
178 (5.63) 165 (13.16)
15.94 (0.14) 15.5 (0.31)
57.61 (0.43) 58.29 (0.77)
189 (5.04) 186 (6.62)
15.91 (0.14) 16.16 (0.22)
55.92 (0.54) 55.21 (1.20)
178 (4.62) 196 (9.37)
14.82 (0.19) 14.56 (0.40)

Figure S1. Experimental manipulation of predation regime: (A) “No predator” treatment:
Small offshore island lacking terrestrial predators and covered with netting to exclude avian predators. (B) Canopy of the island shown in A, illustrating typical brown anole habitat and the use of netting to exclude avian predators. (C) Bahamian racer, Alsophis vudii , ingesting a brown anole. Racers are the primary terrestrial predator of anoles on the main island of Great Exuma, but these and other terrestrial predators were naturally absent from offshore islands. By introducing racers to island exposed to bird predation we created “bird+snake predator” treatments. (D) “Bird predator” treatment: a small offshore island with netting added to control for its structural addition, but left open to expose the canopy to avian predators.
Figure S2. Selection estimates measured across the range of experimentally induced population densities. Selection differentials were measured within each island and were corrected for year effects.

Figure S1

Figure S2