Do group dynamics affect colour morph clines during a range shift?

Area of Science:

• Ecology
• Evolutionary Biology
• Behavioral Ecology

Background:

• Color polymorphism in species can offer ecological advantages at landscape scales.
• Intrapopulational processes, like social interactions, also influence morph frequencies.
• Clinal variation in morph frequencies can be affected by social feedback.

Purpose of the Study:

• Investigate the interplay between morph-specific thermal tolerance, climate, and social environments.
• Understand how social feedback impacts clinal variation in morph frequencies during range expansion.
• Examine the role of social feedback in the context of a color-morph frequency cline in blue-tailed damselflies (Ischnura elegans) in Sweden.

Main Methods:

• Studied reciprocal interactions between morph-specific thermal tolerance, local climate, and social environments.
• Analyzed a color-morph frequency cline associated with a recent range expansion.
• Compared environmental acclimation effects and social feedback mechanisms for different morphs.

Main Results:

• Gynochrome (female-like) cold tolerance correlated positively with local gynochrome frequencies, indicating a frequency-dependent fitness benefit.
• Androchrome (male-mimic) cold tolerance improved after cold weather exposure, suggesting environmental acclimation.
• Contrary to environment-matching predictions, gynochrome frequencies increased at the expanding range limit, suggesting beneficial social feedback in novel climates.

Conclusions:

• Beneficial social effects on environmental tolerances can facilitate species range shifts.
• Social feedback can reverse or counteract typical patterns of intraspecific interactions and environment-matching clines.
• Social feedback plays a crucial role in adaptation and range expansion in species with color polymorphism.