Sexual Selection and Ecological Speciation

Sexual selection and ecological speciation are interlinked evolutionary processes by which biodiversity arises. Sexual selection refers to differential reproductive success arising from mate choice and intrasexual competition, often driving the evolution of elaborate traits or mating behaviours. Ecological speciation occurs when divergent natural selection across different environments leads to reproductive isolation between populations. Interactions between these processes can accelerate, modulate or impede speciation. In many systems, divergent ecological pressures not only shape survival traits but also influence mating preferences for ecologically relevant characters, yielding premating barriers as a by-product of local adaptation. Conversely, variation in secondary sexual traits can modify resource use or habitat choice, feeding back into ecological divergence. The balance of prezygotic and postzygotic barriers, the geographic context (sympatry, allopatry, secondary contact) and genetic architecture determine the trajectory and rate of speciation. Recent advances reveal that sexual selection may enhance speciation by magnifying trait divergence, but it can also inhibit divergence when strong mate choice promotes gene flow. Understanding the interplay between sexual and natural selection is critical to unravelling mechanisms of speciation and the generation of global biodiversity.

Research from Nature Portfolio

Recent studies have used empirical and experimental approaches to quantify how realistic mating preferences affect the speciation process. One investigation of a jumping spider modelled female preference variance under field-informed parameters, revealing that sexual selection commonly generates directional rather than disruptive selection, challenging classical expectations for mate choice driving sympatric speciation. In another study, functional genomics and genome editing in Sulawesian fishes identified a cis-regulatory mutation underlying red male fin colouration, a sexually selected trait. Knockout experiments demonstrated the fitness effects of this gene on mating success and predator interactions, illustrating how genetic underpinnings of sexual dichromatism can contribute to reproductive isolation and local adaptation. Together, these findings underscore the importance of integrating realistic ecological and genetic contexts when evaluating the role of sexual selection in speciation.

Sexual Selection and Ecological Speciation publication trend

The graph below shows the total number of articles in sexual selection and ecological speciation across all publications each year (not limited to Nature Index journals).

Technical terms

Sexual selection: Evolutionary process where differential mating success drives the development of traits that enhance reproductive fitness.

Ecological speciation: Formation of reproductive barriers between populations due to divergent adaptation to distinct ecological environments.

Prezygotic isolation: Mechanisms preventing mating or fertilisation between divergent populations, such as behavioural or temporal barriers.

Postzygotic isolation: Reduced viability or fertility of hybrid offspring following mating between divergent populations.

Assortative mating: Nonrandom mating pattern where individuals preferentially mate with partners resembling themselves in specific traits.

Allochronic speciation: Divergence of populations driven by changes in reproductive timing, such as daily or seasonal activity schedules.

Sympatric speciation: Speciation occurring within a continuous population without geographic separation, often driven by disruptive selection and assortative mating.

References

1. Reproductive isolation arises during laboratory adaptation to a novel hot environment. Genome Biology (2024).
2. Divergent preference functions generate directional selection in a jumping spider. Scientific Reports (2023).
3. Genome editing reveals fitness effects of a gene for sexual dichromatism in Sulawesian fishes. Nature Communications (2021).
4. Sex-specific expression of circadian rhythms enables allochronic speciation. Evolution Letters (2024).
5. Ecological disruptive selection acting on quantitative loci can drive sympatric speciation. npj Systems Biology and Applications (2024).