Integrated phenotypes: understanding trait covariation in plants and animals

Scott Armbruster, Christophe Pelabon, Geir H. Bolstad, Thomas F. Hansen

Research output: Contribution to journalArticlepeer-review

133 Downloads (Pure)


Integration and modularity refer to the patterns and processes of trait interaction and independence. Both terms have complex histories with respect to both conceptualization and quantification, resulting in a plethora of integration indices in use. We review briefly the divergent definitions, uses and measures of integration and modularity and make conceptual links to allometry. We also discuss how integration and modularity might evolve. Although integration is generally thought to be generated and maintained by correlational selection, theoretical considerations suggest the relationship is not straightforward. We caution here against uncontrolled comparisons of indices across studies. In the absence of controls for trait number, dimensionality, homology, development and function, it is difficult, or even impossible, to compare integration indices across organisms or traits. We suggest that care be invested in relating measurement to underlying theory or hypotheses, and that summative, theory-free descriptors of integration generally be avoided. The papers that follow in this Theme Issue illustrate the diversity of approaches to studying integration and modularity, highlighting strengths and pitfalls that await researchers investigating integration in plants and animals.
Original languageEnglish
Pages (from-to)20130245
JournalPhilosophical Transactions of the Royal Society B
Issue number1649
Early online date7 Jul 2014
Publication statusPublished - Aug 2014


Dive into the research topics of 'Integrated phenotypes: understanding trait covariation in plants and animals'. Together they form a unique fingerprint.

Cite this