Assortative Mating in Animals and Its Role for Speciation

Area of Science:

• Evolutionary Biology
• Macroevolution
• Behavioral Ecology

Background:

• Evolutionary theory posits assortative mating (similar individuals mating) promotes speciation via reproductive isolation.
• Macroevolutionary evidence linking assortative mating strength to species richness has been limited.
• Understanding the role of mating patterns in diversification is crucial for evolutionary studies.

Purpose of the Study:

• To test the hypothesis that stronger assortative mating correlates with higher species richness across animal taxa.
• To investigate the macroevolutionary impact of mating behavior on diversification rates.
• To provide a comprehensive, phylogenetically controlled meta-analysis on assortative mating and species richness.

Main Methods:

• A phylogenetically independent meta-analysis was conducted.
• Data comprised 1,447 effect sizes for assortative mating strength from 307 species across 130 families and 14 animal classes.
• Statistical analyses accounted for phylogenetic non-independence to ensure robust conclusions.

Main Results:

• No significant relationship was found between the strength of assortative mating and species richness.
• This lack of correlation held true across major taxonomic groups and different trait categories.
• The study confirmed that animals generally exhibit positive assortative mating (r = 0.35, 95% CI: 0.19-0.52) when phylogeny is considered.

Conclusions:

• Assortative mating strength does not appear to be a significant driver of species richness at the macroevolutionary scale.
• While animals commonly engage in assortative mating, its role in generating broad-scale diversification needs further investigation.
• Future research should focus on the evolutionary causes and consequences of variation in assortative mating within and between species.