Admixture is a driver rather than a passenger in experimental invasions

Area of Science:

• Ecology
• Evolutionary Biology
• Invasion Biology

Background:

• Biological invasions pose significant ecological and economic threats worldwide.
• Understanding the factors that drive the success and spread of invasive species is crucial for effective management.
• Genetic diversity and admixture are hypothesized to influence the invasive potential of species.

Purpose of the Study:

• To investigate the impact of genetic admixture from multiple source populations on the invasive spread of the seed beetle Callosobruchus maculatus.
• To determine if genetic diversity, specifically through admixture, can accelerate the expansion rate of an invasive species.

Main Methods:

• Experimental invasions using the seed beetle Callosobruchus maculatus in a controlled array of linked habitat patches.
• Comparison of invasion dynamics using individuals from single population sources versus mixtures of two, four, or six population sources.
• Application of a model-selection approach to analyze population growth rates and spread.

Main Results:

• Any level of genetic mixture significantly propelled the growth rates and spread of introduced populations.
• Invasions originating from admixed populations exhibited accelerated expansion compared to single-source populations.
• The positive effect of admixture on invasion dynamics was observed across varying degrees of genetic mixing.

Conclusions:

• Genetic admixture, even at low levels, can significantly enhance the invasive success of species.
• Heterosis, resulting from genetic mixing, appears to be a key mechanism driving accelerated range expansion in invasive populations.
• These findings highlight the importance of considering genetic diversity in predicting and managing biological invasions.