Symmetry systems on the wings ofDichromodesGuenée (Lepidoptera: Geometridae) are unconstrained by venation

Abstract

The nymphalid groundplan, an idealized schematic illustrating the essential elements of butterfly wing patterns, predicts a consistent relationship between color pattern and wing venation. Moths in the family Geometridae have wing shapes and patterns that often resemble those of butterflies, and until recently, this family was believed to be among butterflies’ closest relatives. However, an examination of the geometrid genus Dichromodes Guenée, 1858 shows no consistent relationship between the central symmetry system and wing venation. Whereas the distal edge of the central symmetry system is predicted to reach the costal margin proximal to the Subcostal vein in butterflies and acronictine moths, it has no consistent relationship with the Subcostal, Radius, or Radial Sector 1 veins in Dichromodes. This finding highlights developmental diversity that was previously overlooked due to the overwhelming preference for butterflies in studies of lepidopteran wing patterns.

Combinatorial Wnt signaling determines wing margin color patterns of the swallowtail butterfly ground plan

“…The Central Symmetry System represents one of the largest, most diverse, and significant pattern systems in nymphalid butterflies. Its origins are believed to trace back deeply within Lepidoptera, as similar color patterns are frequently observed across various moth species (Nijhout, 1991; Schachat and Brown, 2016; Gawne and Nijhout, 2019; Schachat, 2020). WntA gene expression marks the Central Symmetry System in nymphalids; however, none of our WntA expression or perturbation data had any bearing on color patterns in the middle of the Papilio wings where the Central Symmetry System would be expected.…”

“…The simplicity of the ground plan model and the vast diversity of wing patterns in Lepidoptera have motivated researchers to extend this model to other butterfly and moth families using phenotypic observations (Gardiner and Terblanche, 2010; Suzuki, 2013; Schachat and Brown, 2016; Gawne and Nijhout, 2019; Schachat, 2020). Unfortunately, a lack of developmental data has limited the conclusiveness of this comparative work, in contrast to the expression and knockout studies that have been instrumental in evaluating nymphalid color pattern homologies.…”

Phylogenomics of the geometrid tribe Palyadini (Lepidoptera: Geometridae) reveals contrasting patterns of phylogenetic signal in wing colour characters

“…In the NGP, the eyespots are all treated as serially homologous to one another and subjected to the same developmental pathways (Nijhout, 1991). However since Palyadini are not nymphalids and their colour patterns do not correspond to this model, it is not advisable to assume homology between the pattern elements of NGP and those found in Geometridae in general (Schachat, 2019), even if they could be “process homologous” at a cellular level, as well as phenotypically similar.…”

“…Although lepidopteran wing patterns seem at first like kaleidoscopic mosaics of colours (McKenna et al., 2020), multiple authors have independently regarded them as potential sources of phylogenetic signals and attempted to decode these patterns into homologies by proposing standardized models that identify discrete units later called pattern elements (Nijhout, 1991; Gawne and Nijhout, 2020). The Nymphalid Ground Plan (NGP) (Schwanwitsch, 1924; Süffert, 1927) is the most popular of these models and although it was developed based on only one family of butterflies (Nymphalidae), it has been used subsequently to study the colour patterns of other lepidopteran families as well (Schachat and Goldstein, 2018; Schachat, 2019). Recently though, the efficiency of the NGP to map and predict colour patterns outside Papilionoidea (the superfamily that includes all butterflies) has been called into question (Schachat and Goldstein, 2018; Schachat, 2019) and other models, such as the Arctiid Archetype (Gawne and Nijhout, 2020), have been suggested as a better choice for identifying homologous pattern elements in some groups of moths.…”

“…The Nymphalid Ground Plan (NGP) (Schwanwitsch, 1924; Süffert, 1927) is the most popular of these models and although it was developed based on only one family of butterflies (Nymphalidae), it has been used subsequently to study the colour patterns of other lepidopteran families as well (Schachat and Goldstein, 2018; Schachat, 2019). Recently though, the efficiency of the NGP to map and predict colour patterns outside Papilionoidea (the superfamily that includes all butterflies) has been called into question (Schachat and Goldstein, 2018; Schachat, 2019) and other models, such as the Arctiid Archetype (Gawne and Nijhout, 2020), have been suggested as a better choice for identifying homologous pattern elements in some groups of moths.…”