Sexual Selection Dynamics in Evolutionary Ecology

Sexual selection operates through competition for mates and mate choice, shaping phenotypes from elaborate courtship displays to microscopic gamete strategies. It interacts with natural selection to influence adaptation, genetic diversity and demographic stability. The balance of costs and benefits depends on ecological context, mating system and life-history traits. In harsh or changing environments, sexually selected traits may either bolster population resilience by favouring high-quality alleles or exacerbate extinction risk by diverting resources from survival and reproduction. Mechanistic studies have revealed trade-offs between investment in competitive traits and germline maintenance, while comparative analyses affirm that sexual selection often aligns with natural selection to promote population fitness. Communication modalities, from visual ornaments to chemical cues, mediate sexual selection across taxa, highlighting its pervasive role in driving biodiversity.

Research from Nature Portfolio

Recent work has mapped chemosensory signals as key substrates for sexual selection across the animal kingdom. A broad review demonstrated that chemical communication is under selective pressure in over half of the major phyla, implicating the evolution of production and detection structures in mate assessment and competition. A large-scale synthesis of experimental evolution studies showed that male-biased sexual selection tends to elevate mean fitness traits and reduce variance, particularly under stress, indicating net positive effects on population performance. Complementary genomic analyses have tested the genic capture hypothesis by selecting on male mating success and resequencing entire genomes, revealing that strong sexual selection erodes genome-wide genetic variance and supporting the idea that condition-dependent traits capture underlying mutation load.

Research from all publishers

Experimental work on beetle populations has shown that environmental complexity mitigates the demographic costs of sexual selection. Populations with a history of mate competition maintained larger size and more stable growth under heat stress when housed in structurally complex habitats, suggesting natural environments buffer the fitness trade-offs of costly mating strategies. In seed beetles, experimental evolution under strong sperm competition demonstrated a trade-off between male fertilisation success and germline maintenance: males evolved for competitive ability produced offspring of reduced quality when exposed to social cues, indicating resource allocation decisions can shape mutation rates. Comparative analyses across animals report that net selection is often stronger on males than females, aligning with theoretical predictions and supporting a role for sexual selection in facilitating rapid adaptation by preferentially purging deleterious alleles.

Sexual Selection Dynamics in Evolutionary Ecology publication trend

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

Technical terms

Sexual selection: Differential reproductive success arising from competition for mates and mate choice.

Sperm competition: Postcopulatory contest among sperm from multiple males to fertilise eggs.

Sexual conflict: Evolutionary arms race between male and female reproductive interests leading to counter-adaptations.

Condition dependence: Reliance of sexually selected traits on overall physiological state or genetic quality.

Genic capture hypothesis: Theory that sexually selected traits reflect genome-wide mutation load by capturing genetic variance in condition.

References

1. Environmental complexity mitigates the demographic impact of sexual selection. Ecology Letters (2024).
2. Increased male investment in sperm competition results in reduced maintenance of gametes. PLOS Biology (2023).
3. Chemical communication and its role in sexual selection across Animalia. Communications Biology (2023).
4. Meta-analytic evidence that sexual selection improves population fitness. Nature Communications (2019).
5. Molecular evidence supports a genic capture resolution of the lek paradox. Nature Communications (2019).
6. Stronger net selection on males across animals. eLife (2021).