Sexual dimorphism is a major component of morphological variation across the tree of life, but the mechanisms underlying phenotypic differences between sexes of a single species are poorly understood. We examined the population genomics and biogeography of the common palmfly Elymnias hypermnestra , a dual mimic in which female wing colour patterns are either dark brown (melanic) or bright orange, mimicking toxic Euploea and Danaus species, respectively. As males always have a melanic wing colour pattern, this makes E. hypermnestra a fascinating model organism in which populations vary in sexual dimorphism. Population structure analysis revealed that there were three genetically distinct E. hypermnestra populations, which we further validated by creating a phylogenomic species tree and inferring historical barriers to gene flow. This species tree demonstrated that multiple lineages with orange females do not form a monophyletic group, and the same is true of clades with melanic females. We identified two single nucleotide polymorphisms (SNPs) near the colour patterning gene WntA that were significantly associated with the female colour pattern polymorphism, suggesting that this gene affects sexual dimorphism. Given WntA 's role in colour patterning across Nymphalidae, E. hypermnestra females demonstrate the repeatability of the evolution of sexual dimorphism.
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Wing pattern diversity in Eunica butterflies (Nymphalidae: Biblidinae): phylogenetic analysis implies decoupled adaptive trends in dorsal sexual dimorphism and ventral eyespot evolution
Butterfly eyespots are wing patterns reminiscent of vertebrate eyes, formed by concentric rings of contrastingly coloured scales. Eyespots are usually located close to the wing margin and often regarded as the single most conspicuous pattern element of butterfly wing colour displays. Recent efforts to understand the processes involved in the formation of eyespots have been driven mainly by evo‐devo approaches focused on model species. However, patterns of change implied by phylogenetic relationships can also inform hypotheses about the underlying developmental mechanisms associated with the formation or disappearance of eyespots, and the limits of phenotypic diversity occurring in nature. Here we present a combined evidence phylogenetic hypothesis for the genus
- NSF-PAR ID:
- 10486540
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Cladistics
- Volume:
- 40
- Issue:
- 1
- ISSN:
- 0748-3007
- Format(s):
- Medium: X Size: p. 1-20
- Size(s):
- ["p. 1-20"]
- Sponsoring Org:
- National Science Foundation
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Abstract Habitat-specific thermal responses are well documented in various organisms and likely determine the vulnerability of populations to climate change. However, the underlying roles of genetics and plasticity that shape such habitat-specific patterns are rarely investigated together. Here we examined the thermal plasticity of the butterfly Bicyclus dorothea originating from rainforest and ecotone habitats in Cameroon under common garden conditions. We also sampled wild-caught butterflies from forest and ecotone sites and used RADseq to explore genome-wide population differentiation. We found differences in the level of phenotypic plasticity across habitats. Specifically, ecotone populations exhibited greater sensitivity in wing eyespot features with variable development temperatures relative to rainforest populations. Known adaptive roles of wing eyespots in Bicyclus species suggest that this morphological plasticity is likely under divergent selection across environmental gradients. However, we found no distinct population structure of genome-wide variation between habitats, suggesting high level of ongoing gene flow between habitats is homogenizing most parts of the genome.
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Abstract Automeris moths are a morphologically diverse group with 145 described species that have a geographic range that spans from the New World temperate zone to the Neotropics. Many Automeris have elaborate hindwing eyespots that are thought to deter or disrupt the attack of potential predators, allowing the moth time to escape. The Io moth (Automeris io), known for its striking eyespots, is a well-studied species within the genus and is an emerging model system to study the evolution of deimatism. Existing research on the eyespot pattern development will be augmented by genomic resources that allow experimental manipulation of this emerging model. Here, we present a high-quality, PacBio HiFi genome assembly for Io moth to aid existing research on the molecular development of eyespots and future research on other deimatic traits. This 490 Mb assembly is highly contiguous (N50 = 15.78 mbs) and complete (benchmarking universal single-copy orthologs = 98.4%). Additionally, we were able to recover orthologs of genes previously identified as being involved in wing pattern formation and movement.
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ABSTRACT Background The color patterns that adorn lepidopteran wings are ideal for studying cell type diversity using a phenomics approach. Color patterns are made of chitinous scales that are each the product of a single precursor cell, offering a 2D system where phenotypic diversity can be studied cell by cell, both within and between species. Those scales reveal complex ultrastructures in the sub‐micrometer range that are often connected to a photonic function, including iridescent blues and greens, highly reflective whites, or light‐trapping blacks.
Results We found that during scale development, Fascin immunostainings reveal punctate distributions consistent with a role in the control of actin patterning. We quantified the cytoskeleton regularity as well as its relationship to chitin deposition sites, and confirmed a role in the patterning of the ultrastructures of the adults scales. Then, in an attempt to characterize the range and variation in lepidopteran scale ultrastructures, we devised a high‐throughput method to quickly derive multiple morphological measurements from fluorescence images and scanning electron micrographs. We imaged a multicolor eyespot element from the butterfly
Vanessa cardui (V. cardui ), taking approximately 200 000 individual measurements from 1161 scales. Principal component analyses revealed that scale structural features cluster by color type, and detected the divergence of non‐reflective scales characterized by tighter cross‐rib distances and increased orderedness.Conclusion We developed descriptive methods that advance the potential of butterfly wing scales as a model system for studying how a single cell type can differentiate into a multifaceted spectrum of complex morphologies. Our data suggest that specific color scales undergo a tight regulation of their ultrastructures, and that this involves cytoskeletal dynamics during scale growth.
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null (Ed.)The forewings and hindwings of butterflies and moths (Lepidoptera) are differentiated from each other, with segment-specific morphologies and color patterns that mediate a wide range of functions in flight, signaling, and protection. The Hox gene Ultrabithorax ( Ubx ) is a master selector gene that differentiates metathoracic from mesothoracic identities across winged insects, and previous work has shown this role extends to at least some of the color patterns from the butterfly hindwing. Here we used CRISPR targeted mutagenesis to generate Ubx loss-of-function somatic mutations in two nymphalid butterflies ( Junonia coenia , Vanessa cardui ) and a pyralid moth ( Plodia interpunctella ). The resulting mosaic clones yielded hindwing-to-forewing transformations, showing Ubx is necessary for specifying many aspects of hindwing-specific identities, including scale morphologies, color patterns, and wing venation and structure. These homeotic phenotypes showed cell-autonomous, sharp transitions between mutant and non-mutant scales, except for clones that encroached into the border ocelli (eyespots) and resulted in composite and non-autonomous effects on eyespot ring determination. In the pyralid moth, homeotic clones converted the folding and depigmented hindwing into rigid and pigmented composites, affected the wing-coupling frenulum, and induced ectopic scent-scales in male androconia. These data confirm Ubx is a master selector of lepidopteran hindwing identity and suggest it acts on many gene regulatory networks involved in wing development and patterning.more » « less
