Faster poleward range shifts in moths with more variable colour patterns.

Area of Science:

• Ecology and Evolutionary Biology
• Climate Change Biology
• Zoology

Background:

• Climate change is driving latitudinal and altitudinal range shifts in many species.
• Understanding species traits that facilitate range expansion is crucial for predicting biodiversity responses.
• Previous studies indicate varying poleward shift rates across taxa, time, and locations.

Purpose of the Study:

• To investigate the relationship between species traits and range shift rates in moths.
• To identify traits associated with faster environmental tracking and distribution expansion.
• To improve projections of species' responses to ongoing climate change.

Main Methods:

• Analysis of distribution data for 416 moth species in Sweden from 1973 to 2014.
• Quantification of range limit shifts (km per decade) and correlation with species traits.
• Assessment of factors including inter-individual variation in color patterns, latitude, abundance, and abundance fluctuations.

Main Results:

• Moth range limits in Sweden shifted northward by an average of 52.4 km per decade (expanding species) or 23.2 km per decade (all species).
• Range shift rates increased with higher inter-individual variation in color patterns, suggesting adaptation to changing conditions.
• Northern range limits were positively associated with average abundance and negatively with year-to-year abundance fluctuations, indicating the importance of disperser production.

Conclusions:

• Inter-individual variation in color patterns is a key trait enabling moths to cope with novel environmental conditions and expand their ranges.
• Species abundance and stability influence range dynamics, likely through the production of dispersers.
• Understanding trait-mediated range shifts is vital for biodiversity conservation in the face of climate change.