No association between plant mating system and geographic range overlap.

Area of Science:

• Evolutionary Biology
• Plant Speciation
• Biogeography

Background:

• Automatic self-fertilization (selfing) is hypothesized to influence speciation by promoting reproductive isolation and ecological differentiation.
• Selfing species are predicted to exhibit greater range overlap with their closest relatives compared to outcrossing species.
• The generality of this prediction across diverse plant groups remains empirically untested.

Purpose of the Study:

• To investigate the influence of mating system on range overlap in sister plant species pairs.
• To determine if the relationship between divergence time and range overlap is modulated by mating system.

Main Methods:

• Analyzed range overlap in 98 sister species pairs from 20 genera across 15 families.
• Categorized species pairs based on whether zero, one, or both species are selfers.
• Utilized divergence time estimates from time-calibrated phylogenies to assess temporal effects on range overlap.

Main Results:

• No significant effect of automatic self-fertilization on the range overlap of closely related plant species was detected.
• Sister pairs with more recent divergence times exhibited modestly increased range overlap.
• The effect of divergence time on range overlap was independent of the species' mating system.

Conclusions:

• Mating system appears to play a minor or inconsistent role in shaping the co-occurrence patterns of close relatives.
• Other ecological and evolutionary mechanisms likely exert a stronger influence on the range overlap of sister species.