Table 2.
Frequency of range overlap compared across the three dichotomies from Table 1. Our comparisons are for “young” (DNei ≤ 0.5) species contrasts after phylogenetic correction. The entries are fraction of contrasts with overlapping ranges and the number of comparisons (N). Statistical significance is assessed with a Fisher exact test comparing 2×2 tables with the dichotomy on one axis and sympatry versus allopatry on the other. Following C&O, the criterion for “sympatry” is any range overlap. The data analyzed are from Yukilevich’s web site.
| Dichotomies | Less (N) | More (N) | P across dichotomy | |
|---|---|---|---|---|
| Intrinsic postzygotic isolation | DNei ≤ 0.25 | 0.47 (15) | 0.47 (19) | 1 |
| 0.25 ≤ DNei ≤ 0.5 | 0.5 (12) | 0.6 (20) | 0.85 | |
| Host plant differences | DNei ≤ 0.25 | 0.54 (13) | 0.67 (6) | 0.98 |
| 0.25 ≤ DNei ≤ 0.5 | 0.5 (8) | 0.67 (12) | 0.78 | |
| X-linked loci | DNei ≤ 0.25 | 0.58 (12) | 0.5 (12) | 1 |
| 0.25 ≤ DNei ≤ 0.5 | 0.65 (17) | 1 (1) | 1 | |