Abstract
Phenotypic divergence between closely related species has long interested biologists. Taxa that inhabit a range of environments and have diverse natural histories can help understand how selection drives phenotypic divergence. In butterflies, wing color patterns have been extensively studied but diversity in wing shape and size is less well understood. Here, we assess the relative importance of phylogenetic relatedness, natural history, and habitat on shaping wing morphology in a large dataset of over 3500 individuals, representing 13 Heliconius species from across the Neotropics. We find that both larval and adult behavioral ecology correlate with patterns of wing sexual dimorphism and adult size. Species with solitary larvae have larger adult males, in contrast to gregarious Heliconius species, and indeed most Lepidoptera, where females are larger. Species in the pupal‐mating clade are smaller than those in the adult‐mating clade. Interestingly, we find that high‐altitude species tend to have rounder wings and, in one of the two major Heliconius clades, are also bigger than their lowland relatives. Furthermore, within two widespread species, we find that high‐altitude populations also have rounder wings. Thus, we reveal novel adaptive wing morphological divergence among Heliconius species beyond that imposed by natural selection on aposematic wing coloration.
Highlights
Identifying the selective forces driving phenotypic divergence among closely related species lies at the core of evolutionary biology research
We modelled variation in wing area and aspect ratio sexual dimorphism across species with 203 ordinary least squares (OLS) linear regressions, implemented in the ‘lm’ function
There was a marginally significant phylogenetic signal in sexual size dimorphism (Abouheif’s Cmean=0.24, P=0.05; S.I., Fig. S3), so we repeated the analysis accounting for phylogeny and the results are presented in the Supplementary Information
Summary
Identifying the selective forces driving phenotypic divergence among closely related species lies at the core of evolutionary biology research. In which descendants from a common ancestor rapidly fill a variety of niches, are ideal systems to investigate morphological divergence (Schluter 2000). The study of adaptive radiations has revealed that evolution often comes up with similar solutions for similar problems at the phenotypic and genetic levels (Losos 2010; Marques et al 2019). Speciose groups that have repeatedly and independently evolved convergent adaptations to life-history strategies and environments are good systems in which study selection drivers (Schluter 2000). Adaptive phenotypic evolution is often complex and multifaceted, with more than a single selective force in action (Maia et al 2016; Nosil et al 2018). Integrative approaches that make use of tractable traits across well-resolved phylogenies are needed to explore the selective forces driving phenotypic evolution
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
