Table 2.

Summary of coefficients estimated for the analysis of postzygotic reproductive isolation from the Bufonidae data. The original index of reproductive isolation (left) was calculated by Malone and Fontenot (2008) following the procedure of Coyne and Orr (1989) and Presgraves (2002). The new index (right) takes into account that reproductive barriers are sequential following Ramsey et al. (2003). The confidence intervals are for 95% highest posterior density (HPD) and are significant if they do not include zero (in bold)

Coefficient	Biological meaning	Postzygotic (Original)		Postzygotic (New)
		Lower	Upper	Lower	Upper
μ (intercept)	Average RI	0.2980	0.6945	0.8398	0.9686
βgen.dist.	Slope relating genetic distance and RI	3.6212	5.8819	0.4472	1.2592
${\mathrm{\gamma }}_{\mathrm{sym}}$	Additional RI in sympatry	−0.2816	−0.0427	−0.0988	−0.0105
${\mathrm{\beta }}_{\mathrm{int}}$	Increase in slope for sympatry	0.4679	3.5163	0.2665	1.3992