Recent Climate Change and Historical Population Structure Predict Spatial Patterns of Admixture Between Two...

Area of Science:

• Ecology
• Genetics
• Conservation Biology

Background:

• Human activities significantly impact biodiversity, often increasing hybridization between species.
• Understanding the role of human disturbance in hybridization dynamics requires careful consideration of population structure to avoid spurious correlations.

Purpose of the Study:

• To investigate how human disturbance and population structure influence hybridization between two pine sawfly species, Neodiprion lecontei and Neodiprion pinetum.
• To differentiate the effects of direct (urbanization) and indirect (climate change) human disturbance on sawfly hybridization.

Main Methods:

• Combined environmental data with high-coverage whole-genome resequencing.
• Analyzed population structure and admixture patterns in Neodiprion lecontei and Neodiprion pinetum.
• Employed linear regression models, incorporating genetic principal component scores to control for population structure.

Main Results:

• Neodiprion lecontei and Neodiprion pinetum display distinct population structures, likely due to host-use differences.
• Admixture between species is asymmetric and geographically variable, primarily predicted by indirect human disturbance (climate change).
• A spurious association between direct human disturbance and admixture in Neodiprion pinetum was resolved by accounting for population structure.

Conclusions:

• Indirect human disturbance (climate change) and population structure are key drivers of geographic variation in pine sawfly admixture.
• Accurate identification of environmental predictors for hybridization necessitates robust control for population structure.