Table 5.
Assessment of the relative contribution of pre‐ versus postmating isolation in relation to ecological divergence according to the H–W model. Estimates (±SE) of premating isolation and hybridization are based on the frequency of heterogamous insemination and prevalence of hybrids in either adult or larval populations from Burkina Faso and Cameroon, except for Anopheles arabiensis × Anopheles gambiae s.s. hybridization assessment that is based on populations from East Africa. The parameter m estimates the proportion of nonassortative matings; parameters s and s* estimate the proportional decrease in hybrids from H–W expectations due to assortative mating (s) and total reproductive isolation (s*). The parameter s*/s estimates the proportion of heterogamous inseminations producing viable hybrids in the population, which is a measure of the strength of postmating isolation relative to premating isolation Symbols +, ++, +++, ++++ represent ranks of incresing strength of each parameter
| Hybridizing species (Life Stage, Country) | Proportion mating assortatively (1–m) % | Premating isolation (s) | Hybridization (s*) | Postmating isolation (s*/s) % | Ecological Niche overlap (Pianka's O jk) | Inferred strength of premating isolation | Inferred strength of postmating isolation | Inferred strength of ecological divergence |
|---|---|---|---|---|---|---|---|---|
| An. arabiensis × An. coluzzii (Adults) | 89.3 | 0.01139 (±0.0018) | 0.0025475 (±0.0004491) | 22.4 | 0.717 (±0.111) | +++ | + | + |
| An. arabiensis × An. gambiae s.s. (Adults) | 83.5 | 0.02722 (±0.0082) | 0.0006083 (±0.0002451) | 2.2 | 0.562 (±0.098) | ++ | ++++ | ++ |
| An. coluzzii × An. gambiae s.s. (Adults, BF) | 65.4 | 0.11967 (±0.0400) | 0.014258 (±0.004303) | 11.9 | 0.492 (±0.097) | + | ++ | +++ |
| An. coluzzii × An. gambiae s.s. (Larvae, CM) | 65.4 | 0.11967 (±0.0400) | 0.007238a (±0.001099) | 6.0 | 0.317 (±0.123) | + | +++ | ++++ |
BF, Burkina Faso; CM, Cameroon.
Value doubled because of hemizygosity of males in the larval sample.