Drs. Hannah White, Marlène Gamelon, and Juliano Morimoto have guest edited a Special Feature on Intraspecific Variation in Evolution and Ecology for the Journal of Animal Ecology. They aimed to demonstrate both how intraspecific variation can be measured and incorporated into ecological studies, and its importance in a range of research areas in animal ecology. They also wanted to develop our conceptual and theoretical understanding of intraspecific spatio-temporal variation in natural populations as well as laboratory colonies. You can find the Special Feature here, and hear from the Guest Editors below.

What was the reason for / inspiration behind this Special Feature? Why now?

The adventure started in late 2022. The three of us noticed a surge in popularity of including ecological traits and their functional diversity within the ecological literature. However, many studies considered one single trait value per species, ignoring intraspecific variation. We could observe the same trend across fields in ecology, such as in studies of community ecology, macroecology, demography, population ecology, etc. When one single value per species is considered, we believe this oversimplifies the complexity that exists in nature. What about intraspecific variation? That’s when we decided to propose a Special Feature on this aspect of ecology, to bring together studies that develop our conceptual and theoretical understanding of intraspecific variation in time and space in both natural and laboratory populations. The call for the Special Feature opened in early 2023!

What was the biggest highlight in doing this Special Feature?

We were pleased to see that intraspecific variation is being studied across all biological levels of organisation, and that our Special Feature successfully captured this breadth of topics.   Our Special feature collates studies in a large number of taxa across the Tree of Life, in various ecological contexts (e.g. environmental stressors), from molecules to populations, including intraspecific variation which occurs throughout an individual’s lifespan or among individuals within and among populations.

What was the biggest challenge in doing this Special Feature?

The biggest challenge was clearly linked to the biggest highlight: intraspecific variation is everywhere! How to synthesize all these excellent studies into a general coherent editorial which brings the papers together? After several discussions together, trying to organize this variability, we finally identified three major axes of variation, or dimensions, which enabled us to include intraspecific variation into broader eco-evolutionary contexts and that we hope is a useful framework to guide future studies in the field.

What were the main, overarching insights that came from the papers published in this Special Feature? Were there any surprises?

Although the Special Feature includes papers from a variety of fields within ecology and evolution, there was still a bias towards behavioural and demographic studies over other areas of research, highlighting that studying intraspecific variation above the population level, e.g. within ecological communities, remains a challenge in animal ecology.

However, many insights were still gained from the papers including how incorporating intraspecific variation into eco-evolutionary studies allows us to go beyond correlative patterns of animals and their environment, often revealing mechanistic processes that lead to emergent patterns. Hopefully the aftermath of our Special Feature leads to an increasing interest and awareness of current gaps in the research of intraspecific variation, and that in the future we can run a second edition of this Special Feature highlighting how these gaps have been addressed and the insights this generates.

How do you feel this Special Feature has advanced the field of Intraspecific Variation?

The Special Feature not only reveals the ubiquity of intraspecific variation in nature, but also showcases innovative methods and approaches with which to investigate it. This Special Feature paves the way to future exciting research that we tend to summarize in the section “what’s next?” of our editorial. One of these future directions is definitely to understand how intraspecific variation can lead to broader scale ecological patterns.

We would like to thank our Guest Editors for bringing together an exceptional Special Feature, thank our Senior Editor Professor Jean-Michel Gaillard for overseeing the peer-review process, and thank all of our authors for submitting their work.