Table 2 A list of species, trait type, outbred fitness, inbred fitness values, sample sizes and calculated levels of inbreeding depression for birds, mammals, poikilotherms and plants measured in the wild. Note: <i>X</i><sub>O</sub>=outbred value; <i>X</i><sub>I</sub>=inbred value; outbred <i>n</i> and inbred <i>n</i> are sample sizes; <i>δ</i>=1 – (inbred/outbred); Art.? indicates which species were artificially inbred; <i>F</i>=incidence of inbreeding; Sig.? indicates which estimates of outbred fitness values are significantly greater than inbred fitness values; *indicates that the trait type was inappropriate for the analysis (outbred < inbred), could not be modified and therefore was not used; **indicates that the trait was modified from outbred < inbred to outbred > inbred for the analysis. For traits with more than one entry for <i>X</i><sub>O</sub> and <i>X</i><sub>I</sub>, we have calculated a mean <i>δ</i> estimate for the purpose of the Appendix but used individual estimates for the analysis reported in the text