ZOBODAT - www.zobodat.at Zoologisch-Botanische Datenbank/Zoological-Botanical Database Digitale Literatur/Digital Literature Zeitschrift/Journal: Arthropod Systematics and Phylogeny Jahr/Year: 2017 Band/Volume: 75 Autor(en)/Author(s): Schachat Sandra R. Artikel/Article: Connecting the dots: Spots and bands on the wings of Lichenaula Meyrick, 1890 (Lepidoptera: Gelechioidea: Xyloryctidae) share a uniform relationship with wing venation 363-371 75 (3): 363 – 371 20.12.2017 © Senckenberg Gesellschaft für Naturforschung, 2017. Connecting the dots: Spots and bands on the wings of Lichenaula Meyrick, 1890 (Lepidoptera: Gelechioidea: Xyloryctidae) share a uniform relationship with wing venation Sandra R. Schachat Mississippi Entomological Museum, Mississippi State, MS 39762, USA; Department of Paleobiology, Smithsonian Institution, Washington, DC 20013, USA; Current address: Department of Geological Sciences, Stanford University, Stanford, CA 94305, USA; Sandra R. Schachat [[email protected]] Accepted 26.vi.2017. Published online at www.senckenberg.de/arthropod-systematics on 11.xii.2017. Editors in charge: Monika Eberhard & Klaus-Dieter Klass Abstract Recent studies have shown that wing pattern in various lineages of microlepidoptera follows one of two predictive models. In the first, called the “alternating wing-margin” model, dark and light pattern elements straddle alternating veins along the costal margin of the wing. In the second, called the “uniform wing-margin” model, pattern elements of a single color straddle all veins along the costa. However, of the dozens of families and superfamilies of moths, a small minority have been studied in this context. In the present contribution, the relationship between wing pattern and wing venation is examined in Lichenaula Meyrick, 1890 (Gelechioidea: Xyloryctidae). Species of Lichenaula have wing pattern elements ranging from spots to bands to mottled textures, and they all conform to the uniform wing-margin model. No plausible support was found for the alternating wing-margin model. In previous studies, the relationship between pattern and ve­ nation along the dorsal wing margin has remained unclear due to loss of wing veins and confluence of pattern elements, but certain species of Lichenaula, especially L. maculosa (Turner, 1898), provide evidence that the uniform wing-margin model holds for the dorsum as well as the costa. Previous studies have found that ancestral wing veins continue to influence the development of wing patterns that follow the alternating wing-margin model, even if not expressed in the adult wing, but the wing patterns of Lichenaula suggest that this is not the case for the uniform wing-margin model. Instead, it appears that the only veins that determine the development of wing pattern in Lichenaula are those that are expressed in the adult wing. Considered in preliminary phylogenetic context, it appears that multiple transitions have occurred between the ancestral alternating wing-margin model and the more derived uniform wing-margin model. Key words Color pattern, development, evolution, homology, microlepidoptera, morphology, scales. 1. Introduction The paraphyletic grade microlepidoptera contains tens in microlepidoptera and, more specifically, the relation­ of thousands of species of moths (VAN NIEUKERKEN et al. ship between wing pattern and wing venation (BRAUN 2011), often small and brown; the typically diminutive 1914; VAN BEMMELEN 1916; LEMCHE 1935). This area of size and drab coloration of these moths belies the tremen­ study is now experiencing a revival that began with the dous diversity of their wing patterns. Many decades ago, proposal of a predictive model based on moths in the fam­ various researchers studied the evolution of wing pattern ily Tortricidae (BROWN & POWELL 1991; BAIXERAS 2002). ISSN 1863-7221 (print) | eISSN 1864-8312 (online) 363 Schachat: Wing pattern of Lichenaula "costa" A "costa" Sc3 R1 A "costa"Sc2 Sc3 R1 R2 A Sc1 Sc2 3 1 R2 Sc1 2 Sc R R2 Rs1 Sc1 Sc Rs1 Rs1 Rs2 Rs2 h Rs2 h Rs3 Rs3 Rs3 Rs4 Rs4 Rs4 M1 M1 M1 M2 M2 M2 M3 3A M3 3A 2A M4 M3 2A 5 M4 2A 1A M 4 1A CuA1M5 M 1A CuA2CuA1M5 CuP2CuP1CuA2CuA1 2CuP1CuA2 "dorsum" CuP2CuP1 "dorsum" CuP "costa" B "costa" Sc3 R1 B "costa"Sc2 Sc3 R1 R2 B Sc1 Sc2 3 1 R2 Sc1 2 Sc R R2 Rs1 Sc1 Sc Rs1 Rs1 Rs2 Rs2 h Rs2 h Rs3 Rs3 Rs3 Rs4 Rs4 Rs4 M1 M1 M1 M2 M2 M2 M3 3A M3 3A 2A M4 M3 2A 5 M4 2A 1A M 4 1A CuA1M5 M 1A CuA2CuA1M5 CuP2CuP1CuA2CuA1 2CuP1CuA2 "dorsum" CuP2CuP1 "dorsum" CuP Fig. 1. The two variants of the “wing-margin” model. Either series of pattern elements – "costa" those illustrated in blue, or those illustrated C "costa" Sc3 R1 C "costa"Sc2 Sc3 R1 R2 C Sc1 Sc2 3 1 R2 in red – could develop a dark color. A: The Sc1 2 Sc R R2 Rs1 Sc1 Sc Rs1 Rs1 Rs2 Rs2 original version of the model, called the “al­ Rs2 h ternating wing­margin” model here. B: A hy­ h Rs3 Rs3 Rs3 pothesized intermediate stage based on Sabat­ Rs4 inca demissa. C: The “uniform wing-margin” Rs4 Rs4 model. The wing venation illustrated here is M1 M1 M1 based on a recent update of the plesiomor­ M2 CHACHAT M2 phic groundplan for Lepidoptera (S M2 M3 & GIBBS 2016). — Abbreviations: h: humeral 3A M3 3A 2A M4 M3 2A 5 M4 2A 1A M 4 vein; Sc: subcosta; R: radius; Rs: radial sector; 1A CuA1M5 M 1A CuA2CuA1M5 CuP2CuP1CuA2CuA1 M: media; CuA: anterior cubitus; CuP: poste­ 2CuP1CuA2 "dorsum" CuP2CuP1 "dorsum" CuP rior cubitus; A: anals. This model, now called the “alternating wing-margin” following observations of a handful of species belong­ model, posits that microlepidopteran wing patterns are ing to the micropterigid genus Sabatinca Walker, 1863 based on two alternating series of bands – one light, one (Fig. 1B); these species are derived within the genus and dark – with each band straddling one vein along the cos­ distantly related to each other, so wing patterns follow­ tal margin of the wing (Fig. 1A). Support for this model ing the uniform wing­margin model were interpreted has been found in various genera of Micropterigidae, a as representing a derived, convergent state (SCHACHAT family that occurs within the most early-diverging lin­ & BROWN 2016). In Psychidae, very few wing patterns eage of Lepidoptera (SCHACHAT & BROWN 2015, 2016). match the alternating wing-margin model, and such an The predictive power of this model was further bolstered interpretation relies on assumptions about the fusion of by empirical confirmation of one of the model’s key as­ wing veins that are very difficult to test; however, many sumptions, a primitive 3-branched Sc vein for Lepido- psychid wing patterns follow the uniform wing-margin ptera (SCHACHAT & GIBBS 2016). model precisely (SCHACHAT & BROWN 2017). And in the However, the lepidopteran tree of life includes many tineid genus Moerarchis Durrant, 1914, color pattern in dozens of microlepidopteran families other than Micro­ some specimens follows the alternating wing­margin pterigidae and Tortricidae (VAN NIEUKERKEN et al. 2011), model near the apex of the wing, but the uniform wing- and support for the alternating wing­margin model in margin model holds more broadly (SCHACHAT 2017). these families has been equivocal thus far. At present, Because the alternating wing-margin model holds for only a few representatives of a few families have been the most basal Sabatinca species and for most other mi­ studied in this context. The wing patterns of tineoid cropterigid genera with patterned wings, this variant of moths most closely follow the “uniform wing-margin” the wing-margin model very likely represents the ances­ model, in which every single vein along the wing costa tral state for lepidopteran wing pattern. And because the – as opposed to every other vein – is surrounded by a alternating wing-margin model holds for Tortricidae as pattern element of the same color (Fig. 1C). This vari­ well, it could plausibly be used to predict wing pattern ant of the “wing-margin” model was originally proposed in any lineage of microlepidoptera. Because the uniform 364 ARTHROPOD SYSTEMATICS & PHYLOGENY — 75 (3) 2017 Fig. 2. Watercolor illustrations of Lichenaula specimens from four species, dorsal views. Courtesy of Celia L. Curtis. wing-margin was inspired by derived, distantly related BROWN 2017; SCHACHAT 2017), but the Gelechioidea have micropterigid species and is not yet known to hold for not yet been examined in this context. Lichenaula there­ any other monotrysian moths, it likely represents a com­ fore presents an opportunity to broaden the morphologi­ mon homoplastic character state. cal and taxonomic scope of this growing area of inquiry. A number of unresolved issues remain with regards to the relationship between wing pattern and venation in microlepidoptera. No examination of any single lineage has yet found full and unequivocal support for the uni­ 2. Materials and methods form wing-margin model. Furthermore, the frequency of wing patterns following the alternating and uniform wing-margin models is still not known. Lastly, many mi­ All species examined are listed in Table 1. All specimens crolepidoptera have speckled or mottled wing patterns; examined here belong to the genus Lichenaula and are such patterns were included in a broad overview of the held in the Australian National Insect Collection in Can­ Psychidae (SCHACHAT & BROWN 2017) but have otherwise berra, Australia. Only forewings were examined because received no attention. hindwings do not have any color pattern. The methods The Australian genus Lichenaula Meyrick, 1890 used here parallel those of recent studies (SCHACHAT & belongs to the subfamily Xyloryctinae (Xyloryctidae), BROWN 2017; SCHACHAT 2017). in the superfamily Gelechioidea (HODGES 1998; KAILA To observe the relationship between wing pattern 2004; KAILA et al. 2011; HEIKKILÄ et al. 2011). This ge­ and wing venation, the clearing agent Histolene was ap­ nus contains species with a variety of wing patterns: plied to individual forewings.