[DSRP Evidence](https://dsrpevidence.org/)

# Interactions between Mechanisms of Reproductive Isolation

Blanckaert et al., 2026, The American Naturalist — Evolutionary Biology

Patterns: [Distinctions](https://dsrpevidence.org/pattern/distinctions), [Relationships](https://dsrpevidence.org/pattern/relationships)

## In short

Species boundaries emerge from the interaction of ecological, behavioral, and genetic isolation mechanisms rather than from any single factor alone, independently instantiating Distinction and Relationship (webs of causality).

## What they found (results)

Modeling local adaptation, mate choice, and genetic incompatibilities together, the authors found that ecological differentiation evolves first and provides the strongest reproductive barrier, while sustained gene flow prevents genetic incompatibilities from accumulating even when other isolation mechanisms are present.

## Abstract

Speciation is responsible for the diversity of species observed today and corresponds to the buildup of reproductive isolation between populations. Reproductive isolation can be generated by different mechanisms that have been extensively characterized, yet how their interactions affect speciation remains largely unknown. Here, we explicitly model the interaction of three key mechanisms (local adaptation, mate choice, and genetic hybrid incompatibilities), quantifying their relative contribution to the evolution of reproductive isolation. We modeled two populations exchanging migrants using Fisher’s geometric model for local adaptation, phenotype matching for mate choice, and multiple pairs of Bateson-Dobzhansky-Muller incompatibilities. All three mechanisms were determined by the same set of loci, creating conditions for interactions between barriers at both the genetic and the population level. We found very few cases where the three barriers evolved together. Instead, two barriers could evolve depending on the migration rate: either local adaptation and genetic incompatibilities for limited migration or local adaptation and mate choice for higher migration. Our results show that local adaptation due to ecological differentiation was the first to evolve and by far the most effective reproductive barrier. Finally, we demonstrated that in a polygenic model, populations could become locally adapted and evolve strict mate choice, yet they would not accumulate incompatibilities provided there was sufficient gene flow.

These researchers were not testing DSRP. The finding is theirs; the correspondence to DSRP is drawn by this site.

[Source](https://doi.org/10.1086/740888)