Wing color pattern revisited: non-mimetic species help understand the evolution of mimicry in Zetherini (Nymphalidae, Satyrinae)

Wing color pattern revisited: non-mimetic species help understand the evolution of mimicry in Zetherini (Nymphalidae, Satyrinae) Carla M. Penz Department of Biological Sciences, University of New Orleans, 2000 Lakeshore Dr. New Orleans, LA 70148, USA. Research Associate, American Museum of Natural History. Courtesy Curator, Department of Natural History, Florida Museum of Natural History. Email: [email protected]; https://orcid.org/00000002-2544-3508 Date of issue online: 19 December 2025 Electronic copies (ISSN 2575-9256) in PDF format at: https://journals.flvc.org/troplep; https://zenodo.org; archived by the Institutional Repository at the University of Florida (IR@UF), http://ufdc.ufl.edu/ufir; DOI: 10.5281/zenodo.17860818 © The author(s). This is an open access article distributed under the Creative Commons license CC BY-NC 4.0 (https://creativecommons.org/ licenses/by-nc/4.0/). Abstract: This comparative study describes and illustrates the color pattern of 23 species in the Satyrinae tribe Zetherini, which currently includes six genera. Here I expand the taxonomic representation from my previous work, thus allowing me to revise the descriptions of some color pattern elements and correct an error of interpretation. While some Zetherini taxa are cryptic, others show mimetic resemblance to members of the tribe Danaini. As working hypotheses, using the color pattern of non-mimetic Zetherini genera as a starting point, morphological pathways for the evolution of mimicry are proposed. The potential for multiple events of evolution of mimicry within the Zetherini is discussed, and observations on natural history and behavior are compiled from the literature. Keywords: Danaini; eyespots; pattern elements; Southeast Asia. 99TROP. LEPID. RES., 35(2): 99-116, 2025PENZ: Mimicry in Zetherini INTRODUCTION The Old World butterfly tribe Zetherini presently includes six genera, and the phylogenetic relationships among these taxa are relatively well understood (Fig. 1). The analyses by Peña et al. (2006), Wahlberg et al. (2009), Chazot et al. (2021) and Kawahara et al. (2023) consistently grouped Neorina with Penthema and Zethera with Ethope, while Xanthotaenia appeared as the first split within Zetherini (the latter was not studied by Peña et al., 2006). The genus Callarge was classified in the Zetherini by Miller (1968), and grouped with Penthema in the analyses by Yang & Zhang (2015) and Kawahara et al. (2023). Note that the aforementioned phylogenetic studies included only a small number of species (e.g., six species in Kawahara et al., 2023). The Zetherini phylogeny (Fig. 1) has important implications for the evolution of wing coloration. Xanthotaenia busiris (Westwood, 1858) is the earliest diverging taxon in the tribe and has a cryptic color pattern (Fig. 1a). The remaining five genera are split into two groups that differ phenotypically. Species of Neorina are cryptic and presumably non-mimetic (Fig. 1b, but see Discussion), while the color patterns of Penthema and Callarge (Fig. 1c, e) resemble Idea, Euploea and Tirumala (Nymphalidae, Danainae) to varying degrees (Fruhstorfer, 1927; Igarashi & Fukuda, 1997). The non-mimetic P. adelma (C. Felder & R. Felder, 1862) appears to be an exception within Penthema (Fig. 1d). On the other hand, species in the sister genera Ethope and Zethera have evolved broadly different color patterns. While Ethope himachala (Moore, 1857) is cryptic (Fig. 1f), its mimetic, sexually monomorphic congeners (Fig. 1g) resemble Euploea species that have oval-shaped white markings along the hind wing outer margin (VaneWright & Huggins, 1972). Four out of six species of Zethera show female-limited mimicry (Fig. 1h), while both sexes are mimetic in two species. The mimetic pattern in this genus is complex, as sexually dimorphic and sexually monomorphic species converge on broadly different models (Vane-Wright & Smiles, 1975). In sum, although the tribe currently includes only 23 species, there is considerable color pattern variation in Zetherini. Considering the phylogenetic relationships among genera and their convergence onto different model taxa, mimicry might have evolved multiple times in this group (see Discussion). Schwanwitsch (1924) and Süffert (1927) independently proposed nearly identical systems outlining and naming butterfly wing color bands and eyespots. Although their studies constituted the basis for what is known today as the ‘nymphalid ground plan,’ the terminology for such bands has been revised (Nijhout 1978, 1985, 1991; Nijhout & Wray 1986); summarized in Fig. 2. Establishing a positional correspondence of serial bands (i.e., pattern elements) across species allows researchers to propose hypotheses for butterfly color pattern evolution. This can be approached through comparative morphology, genetic and/or developmental frameworks. Numerous butterfly species have evolved mimetic resemblance to distantly related taxa (see Quicke (2017) for examples). The genetic and developmental processes involved in mimicry have been studied in detail for several butterfly taxa, starting with the seminal Papilio crosses of Clarke & Sheppard (1959, 1960 a, b, c, d) and extending to modern genomics of Heliconius (e.g., Kronforst & Papa, 2015; Van Belleghem et al., 2020). Nonetheless, because mimicry has evolved 100 TROP. LEPID. RES., 35(2): 99-116, 2025 PENZ: Mimicry in Zetherini independently in various butterfly taxa, a useful starting point to stimulate and inform future research on the evolution of mimicry entails the identification and description of ground pattern elements and other wing color components. Based on a sample of six species in four genera, I attempted to identify and compare color pattern elements and homologous color bands between mimetic and non-mimetic Zetherini (Penz, 2017). That study recognized that a pale-colored band flanked by nymphalid ground plan elements f and g varies considerably among species (see Fig. 2 for identification of pattern elements). Here, I refer to such a band as being ‘associated’ with elements f and g, a terminology that is also used for other colored bands (e.g., between elements c and d). Penz (2017: Figure 2.6b-c, g) showed that the band associated with elements f and g is yellow, broad and continuous in Neorina hilda Westwood, 1850, but it is fragmented into white horizontal lines in Penthema lisarda (Doubleday, 1845) and female Zethera pimplea Erickson, 1834. This fragmentation is involved in the mimetic convergence of Penthema and Zethera onto their danaine models. Although that study (Penz, 2017) represented a first step towards understanding color pattern variation in Zetherini, the limited taxon sampling led to some problems. Examining only a few species of Zethera did not allow me to explore the nuances of color pattern variation within the genus, which led to an error in the interpretation of wing color components of Z. pimplea males (Penz, 2017: Figure 2.6g). A more comprehensive comparative study was thus warranted. The present study revisits and expands on my previous work by investigating all 23 currently recognized species of Zetherini. Fifteen species were studied from collection specimens and photographs; eight species were studied exclusively from photographs. An abundance of digital images showing subspecific variation is available online, but documentation of intraspecific color pattern variation is beyond the scope of this study. Here, I seek to answer the following questions within the context of the nymphalid groundplan: (1) What pattern elements and other color components are visibly expressed in non-mimetic Zetherini? (2) What wing pattern and color components were modified by evolution to produce mimetic resemblance in Zetherini? Accordingly, I provide genus-level descriptions along with illustrations showing colorcoded nymphalid groundplan pattern elements, and discuss Figure 1. Genus-level phylogenetic tree for Zetherini based on Chazot et al. (2021) and Kawahara et al. (2023). For each genus, male specimens of the type species (t) are illustrated unless indicated otherwise, and other relevant examples are also shown. The number of currently recognized species, the number of mimetic species, and the number of species that show female-limited mimicry are indicated (see Material and Methods, Mimicry). a, Xanthotaenia busiris (t). b, Neorina hilda (t). c, Penthema lisarda (t). d, Penthema adelma. e, Callarge sagitta (t). f, Ethope himachala (t). g, Ethope diademoides. h, Zethera pimplea (t) non-mimetic male (left) and mimetic female (right). The same specimens appear in other figures with their corresponding locality data. Specimens and Images Below is a list of examined specimens from the following museums: American Museum of Natural History (AMNH); The Natural History Museum, London (BMNH); Florida Museum of Natural History, McGuire Center for Lepidoptera (FLMNH); Milwaukee Public Museum (MPM). Male sex is abbreviated M; female sex, F. Photographs of collection specimens from D’Abrera (1985) and Ek-Amnuay (2012) were also examined. Digital images of live specimens were obtained through iNaturalist website (www.inaturalist.org, all last consulted in November 2024). The Funet web pages for Zetherini genera include current taxonomy (as of September 2025) plus links to iNaturalist observations and images posted in other websites (see below, all image links were last accessed in July 2024). Note that the links listed below constitute only a sample of the images consulted during the course of this study. Readers can visit GBIF.org for open-source images, distribution information, and other data. Those concerned with the permanence of internet resources might wish to download copyright-free images for future reference. Xanthotaenia Westwood, 1858 (one species) https://ftp.funet.fi/pub/sci/bio/life/insecta/lepidoptera/ditrysia/papilionoidea/ nymphalidae/morphinae/xanthotaenia/#Xanthotaenia Collection specimens Xanthotaenia busiris (Westwood, 1858): M, no data, CMP 01-84 (MPM); M, Br. North Borneo [Malaysia], Mt. Kinabalu, 8 May 1903, CMP 07-120 (MPM); M, Malaysia, Singapore, Dec 1976 - Feb 1977, CMP 08-15 (FMNH); M, [Indonesia] N. of Nias I., Oct-Dec 1895, CMP 08-13 (FMNH); M, [Indonesia] Sumatra, [locality not legible] (FMNH); F, Br. North Borneo [Malaysia], Mt. Kinabalu, 8 May 1903, CMP 01-85 (MPM); F, [Indonesia] N. of Nias I., OctDec 1895, CMP 08-14 (FMNH); F, Br. North Borneo [Malaysia], Mt. Kinabalu, 8 May 1903 (MPM); F, W Malaysia, Cameron Islands, 27 Jul 1967 (FMNH); F, SE Borneo (FMNH). Select digital images https://www.inaturalist.org/taxa/501304-Xanthotaenia-busiris http://yutaka.it-n.jp/sat/40560001.html Neorina Westwood, 1850 (five species) https://ftp.funet.fi/pub/sci/bio/life/insecta/lepidoptera/ditrysia/papilionoidea/ nymphalidae/satyrinae/neorina/ Collection specimens Neorina hilda Westwood, 1850 (type species): M, [India] Sikkim, Ari to Gnatong, Apr [18]94 (BMNH); F, [India] Sikkim, 1887 (BMNH). N. lowii (Doubleday, 1849): M, no data (MPM); M, no data (MPM); F, no data (MPM); F, Iraman (sic), 24 Oct 1973 (MPM). N. crishna (Westwood, 1851): M, Java, Soekahoem (FLMNH); F, Java (FLMNH). N. patria Leech, 1891: M, [China] Ta-tsen-Lou (sic; currently Kangding), 1906 (BMNH); M, China, Omai (AMNH); M, [India] Assam, Khasia Hills (FLMNH); F, [China] Tien-Tsuen Yuin-Kin (currently Tianquan), 1899 (BMNH) [India] Assam (FLMNH). Select digital images https://www.inaturalist.org/taxa/470050-Neorina-crishna http://yutaka.it-n.jp/sat/40510010.html https://www.inaturalist.org/taxa/470048-Neorina-hilda https://www.inaturalist.org/taxa/470049-Neorina-lowii https://www.inaturalist.org/taxa/716923-Neorina-lowii-neophyta http://yutaka.it-n.jp/sat/40520010.html https://www.inaturalist.org/taxa/470051-Neorina-patria http://yutaka.it-n.jp/sat/40490010.html http://yutaka.it-n.jp/sat/40500001.html Penthema Doubleday, 1848 (five species) https://ftp.funet.fi/pub/sci/bio/life/insecta/lepidoptera/ditrysia/papilionoidea/ nymphalidae/satyrinae/penthema/ the role of venous and inter-venous elements in mimetic phenotypes. I hypothesize that, among Zetherini genera, mimetic resemblance could be achieved by modification of different pattern elements and associated color bands, thus suggesting that mimicry evolved multiple times within this tribe. As this work relies solely on collection specimens and photographs, I compiled observations on natural history and behavior from the literature. Such information is relevant to the study of wing color pattern evolution, and it balances my limited field experience with this butterfly group. Valuable directions for future work include, but are not limited to, assessing palatability, behavior, and population biology of both models and mimics, and investigating the genetic and developmental bases of wing color pattern in Zetherini. MATERIAL AND METHODS Mimicry Previous studies have pointed to mimetic resemblance between species of Zetherini and putative models. Here, to preliminarily classify taxa as mimetic or non-mimetic, I follow the views of various authors that resulted from field observations or comparison of museum specimens (Fruhstorfer, 1927; Vane-Wright & Huggins, 1972; Vane-Wright & Smiles, 1975; Igarashi & Fukuda, 1997, 2000; Monastyrskii, 2005). 101 Figure 2. Diagram adapted from Nijhout (1991), showing the colorcoded wing pattern elements based on the terminology proposed by Nijhout & Wray (1986) and Nijhout (1991). Wing veins are labelled following Wooton (1979). TROP. LEPID. RES., 35(2): 99-116, 2025PENZ: Mimicry in Zetherini 102 Collection specimens Penthema lisarda (Doubleday, 1845) (type species): M, [India, Assam?] Abr Hills (sic), Aug [19]13 (BMNH); F, [India] Assam, Digboi (BMNH). P. adelma (C. Felder & R. Felder, 1862): M, [China] Shanghai (BMNH); M, West China, Szu-chuan, abt. 30o N 102.5o E, Ta-Tsien-lou, 1910 (FLMNH); F, China, Shanghai (BMNH); F, [China] Ta-Tsien-lou, 1906 (FLMNH). P. darlisa Moore, 1878: M, no data (FLMNH). P. formosanum Rothschild, 1898: M, Formose (FLMNH); F, Taiwan (FLMNH). Select digital images https://www.inaturalist.org/taxa/496346-Penthema-lisarda https://www.inaturalist.org/taxa/1184478-Penthema-lisarda-lisarda https://www.inaturalist.org/taxa/779239-Penthema-adelma https://www.inaturalist.org/taxa/780072-Penthema-darlisa http://yutaka.it-n.jp/sat/40580020.html http://yutaka.it-n.jp/sat/40580030.html https://www.inaturalist.org/taxa/596492-Penthema-formosanum https://www.inaturalist.org/taxa/1418103-Penthema-binghami https://en.wikipedia.org/wiki/Penthema Callarge Leech, 1892 (two species) https://ftp.funet.fi/pub/sci/bio/life/insecta/lepidoptera/ditrysia/papilionoidea/ nymphalidae/satyrinae/callarge/ Collection specimens Callarge sagitta (Leech, 1890) (type species): M, “Japan”, probably from East China (BMNH). C. occidentalis Leech, 1890: M, [China, Sichuan] Moupin (currently Muping Town) 1898 (BMNH). Select digital images https://www.inaturalist.org/taxa/1023897-Callarge-sagitta http://yutaka.it-n.jp/sat/40485010.html Ethope Moore, 1866 (four species) https://ftp.funet.fi/pub/sci/bio/life/insecta/lepidoptera/ditrysia/papilionoidea/ nymphalidae/satyrinae/ethope/ Collection specimens Ethope himachala (Moore, 1857) (type species): M, H Tanjaw (sic) [India, Thanjavur?], Feb 6 [19]27 (BMNH); F, [locality not legible] Feb [19]27 (BMNH). E. diademoides (Moore, 1878): M, [locality not legible], 1-12-[18]92 (BMNH); F, Burma, Karen Hills, Apr 1922 (BMNH). Select digital images https://www.inaturalist.org/taxa/484278-Ethope-himachala https://www.inaturalist.org/photos/12949954 https://www.inaturalist.org/taxa/885772-Ethope-diademoides https://www.inaturalist.org/taxa/885776-Ethope-henrici https://www.inaturalist.org/taxa/884095-Ethope-noirei http://yutaka.it-n.jp/sat/40550001.html Zethera Felder, 1861: (six species) https://ftp.funet.fi/pub/sci/bio/life/insecta/lepidoptera/ditrysia/papilionoidea/ nymphalidae/satyrinae/zethera/ Collection specimens Zethera pimplea (Erichson, 1834) (type species): M, Philippines, Queyou (sic) (FMNH); F, Philippines, San Pablo City, 15 Mar [19]62 (FMNH). Z. musa C. Felder & R. Felder, 1861: M, [Philippines] Mindanao, Margosatubig (BMNH); F, [Philippines] Mindanao, Pasananca Valley (BMNH). Z. musides Semper, 1878: M, Ticao, Philippine Islands, May 1902 (BMNH); F, Cebu, Philippines (BMNH). Select digital images https://www.inaturalist.org/taxa/341787-Zethera-pimplea https://www.inaturalist.org/taxa/847743-Zethera-musa https://www.inaturalist.org/taxa/1147156-Zethera-musides https://www.inaturalist.org/taxa/1110073-Zethera-thermaea https://www.inaturalist.org/taxa/703729-Zethera-hestioides https://www.inaturalist.org/taxa/1441651-Zethera-incerta Preparation of illustrations and terminology Photographs of museum collection specimens were taken with a Sony Alpha 6000 digital camera. Images posted online were used to supplement the sample of museum collections specimens. Authorization was granted to use all copyrightprotected images, and credits and locality data for all images appear in the Figure legends. Images were edited using Adobe Photoshop ®. Here, I utilize the terminology for the nymphalid groundplan pattern elements outlined by Nijhout & Wray (1986) and Nijhout (1991), who used letters of the alphabet to name basal (b, c), central (d, e, f) and border (g, h, i, j) color pattern elements. Venation terminology follows Wooton (1979). Figure 2 (adapted from Nijhout, 1991) illustrates both color pattern elements and venation. RESULTS This study proposes two revisions from my previous work (Penz, 2017) by (1) highlighting the potential role of venous and intervenous pattern elements in the formation of mimetic phenotypes, and (2) correcting an error in the interpretation of color pattern in Zethera pimplea males. In the figures presented here, several nymphalid groundplan pattern elements that can be identified in non-mimetic Zetherini species are represented by solid lines. Most groundplan pattern elements are nonetheless not visible in mimetic taxa. The putative position of non-visible pattern elements associated with particular pale-colored bands is indicated by dotted lines. Pale-colored bands and eyespots are selectively marked with arrow points color coded by potential homology. These arrow points help understand how non-mimetic color components might have been altered by evolution to produce mimetic resemblance. In the descriptions that follow, serial element h is referred to as eyespot(s) as it constitutes a landmark wing pattern element. Non-mimetic taxa Xanthotaenia Xanthotaenia busiris is sexually monomorphic (Fig. 3a, b), and the predominantly brown color pattern of this species can be considered cryptic against the forest leaf litter (Fig. 3c). Like many other cryptic satyrines, the dorsal pattern is a simplified version of the ventral pattern. The dorsal forewing of X. busiris has a yellow transverse band associated with elements f and g (which are not visible, but are indicated by dotted lines in Fig. 3a, b), and a conspicuous white eyespot below vein Rs4. There are no visible pattern elements on the dorsal hind wing. Four pattern elements can be identified on the ventral forewing, and the cross bar and eyespot below Rs4 constitute a mirror image of the dorsal surface (visible even when the butterfly rests with its wings closed, Fig. 3c). The serial eyespots are expressed differently from the costal to the anal forewing margin, and the transverse band seems to interfere with the expression of an eyespot below CuA1 near the wing tornus. The ventral hind wing pattern includes eight recognizable elements that, except for the eyespots, form a series of wavy lines (Fig. 3a). The eyespots vary in size and complexity from the costal to the anal wing margin, with the eyespot below Rs being the largest. It is worth noting that the pair of eyespots below Sc+R and Rs are more conspicuous among all hind wing eyespots. The eyespot below CuA2 is larger than its adjacent eyespots. TROP. LEPID. RES., 35(2): 99-116, 2025 PENZ: Mimicry in Zetherini pale ring that expands beyond the limit of the cell (Fig. 5). This eyespot is flanked by two small white eyespots (below Rs4 and M2), and additional ones are sometimes present (below Rs3 and M3). Neorina crishna (Fig. 5a, c) and N. lowii (Fig. 5b, d) show eyespots below forewing vein M3 (some variation occurs, as per examination of online photographs). Elements i and j are visible on the dorsal hind wing of all Neorina species, but the pale band associated with these elements (more clearly viewed on the ventral surface) is much larger in N. lowii than in others, where it is limited to the hind wing apex (Fig. 5b, d). Dorsal hind wing eyespots are present only in N. crishna and N. lowii (below M3 and CuA1, and sometimes also below M2 and below CuA2 in N. crishna; as per examination of online photographs). Three pattern elements can be identified on the ventral forewing of all Neorina species, namely the eyespots plus elements i and j. A larger number of eyespots are visible on the ventral than on the dorsal surface of the forewings, but they are not visible where the transverse band associated with elements f and g is Neorina The five species of Neorina are sexually monomorphic and have a dark brown background color (Fig. 4 and 5). Barring their difference in size, overall, the appearance of N. hilda resembles that of Xanthotaenia busiris (compare Fig. 4a, c to Fig. 3a, b). The dorsal wing surfaces of all Neorina species show fewer pattern elements than the ventral ones. The dorsal forewing has a complete, yellow or off-white transverse band (Fig. 4ad; 5a, c), except for N. lowii where this band is confined to the space below CuA2 (Fig. 5b, d). The forewing transverse band associated with elements f and g extends into the discal cell and it blends with a smaller band associated with elements c and d (pattern elements c-f are indicated by dotted lines in Fig. 4a, b; 5a). It is unclear whether pattern element e is expressed on the forewing of Neorina. Depending on the species, three to five eyespots are visible on the dorsal forewing. The eyespot below M1 is the largest and it is composed of a dark spot with a small white pupil in all species (Fig 4, 5), sometimes outlined by a 103 Figure 3. Collection specimens showing hypothesized dorsal and ventral pattern elements, color-coded. Solid lines represent visible pattern elements, dotted lines represent the putative position of pattern elements that are not visible. Dorsal wing surface on the left-hand side, ventral on the right. a, Xanthotaenia busiris male, northern Borneo [Sabah, Malaysia], Mt. Kinabalu. b, X. busiris female, same locality as male, arrow indicates a forewing band likely associated with pattern elements f and g. c, live X. busiris on the leaf litter; Thailand, Narathiwat, Waeng, photo by Vatcharavee Sriprasertsil. d, Callarge sagitta male, probably from eastern China, arrow indicates the modified band presumed homologous with that shown in X. busiris. See Material and Methods for museum deposition and locality data of collection specimens. TROP. LEPID. RES., 35(2): 99-116, 2025PENZ: Mimicry in Zetherini 104 expressed near the wing tornus. The ventral hind wing pattern includes four to seven elements, depending on the species. Here, the eyespots plus elements e, i and j are visible in all Neorina species, while c, d and f may be visible in some of the wing cells, depending on the species. In species that have a tail on vein M3, element f is not continuous across the hind wing, but displaced distally in the m3 cell (compare the tail-less N. hilda in Fig. 4a with tailed N. crishna in Fig. 5a). The ventral hind wing eyespots vary in size and complexity across species, with that below Rs being the largest in all Neorina species. The eyespots below vein M3 are larger on the dorsal than the ventral wing surface in both sexes of N. crishna and N. lowii (Fig. 5). Figure 4. Collection specimens showing hypothesized dorsal and ventral pattern elements, color-coded. Solid lines represent visible pattern elements, dotted lines represent the putative position of pattern elements that are not visible. Dorsal wing surface on the left-hand side, ventral on the right. a, Neorina hilda male, India, Sikkim, arrows indicate a forewing band likely associated with pattern elements f and g and a hind wing band associated with parafocal elements i and j. b, N. patria male, China, Ta Tsien Loû, arrows indicate a hind wing band associated with parafocal elements i and j. c, Neorina hilda female, India, Sikkim. d, N. patria female, China, Tien Tsuen. See Material and Methods for museum deposition and locality data of collection specimens. TROP. LEPID. RES., 35(2): 99-116, 2025 PENZ: Mimicry in Zetherini and prominent features of this species include a white transverse band associated with pattern elements f and g plus a discal band seemingly located between elements c and d; these bands are present on both surfaces of the forewing. A faint, broken ventral hind wing band likely associated with element f is visible in some specimens (variable in span as per examination of online Mimetic taxa Penthema Four of five currently recognized Penthema species have pale markings on a brown background color and mimic danaines. Only P. adelma appears to be non-mimetic (Fig. 6a, c) 105 Figure 5. Collection specimens showing hypothesized dorsal and ventral pattern elements, color-coded. Solid lines represent visible pattern elements, dotted lines represent the putative position of pattern elements that are not visible. Dorsal wing surface on the left-hand side, ventral on the right. a, Neorina crishna male, Indonesia, Java, arrows indicate a forewing band likely associated with pattern elements f and g and a hind wing band associated with parafocal elements i and j. b, N. lowii male, no data, arrows indicate a forewing band likely associated with pattern elements f and g and a hind wing band associated with parafocal elements i and j. c, Neorina crishna female, Indonesia, Java. d, N. lowii female, no data. See Material and Methods for museum deposition and locality data of collection specimens. TROP. LEPID. RES., 35(2): 99-116, 2025PENZ: Mimicry in Zetherini 106 Figure 6. Collection specimens showing hypothesized dorsal and ventral pattern elements, color-coded. Solid lines represent visible pattern elements, dotted lines represent the putative position of pattern elements that are not visible. Dorsal wing surface on the left-hand side, ventral on the right. a, Penthema adelma male, China, Shanghai, arrows indicate a forewing band likely associated with pattern elements f and g and c and d, plus a hind wing band associated with parafocal elements i and j. b, P. lisarda male, India, possibly Assam, Abr Hills (sic), arrows indicate a forewing band likely associated with pattern elements f and g and c and d, plus a hind wing band associated with parafocal elements i and j; the illustration on the left shows the previously published interpretation of color pattern elements, which is revised here to hypothesize a prevalence of venous and intervenous pattern elements in the formation of mimetic patterns. c, P. adelma female, China, Shanghai (dorsal and ventral images flipped horizontally for consistency). d, P. lisarda female, India, Assam, Digboi. In the female images, lines indicate corresponding forewing bands and eyespots of the putatively non-mimetic P. adelma and mimetic P. lisarda. See Material and Methods for museum deposition and locality data of collection specimens. TROP. LEPID. RES., 35(2): 99-116, 2025 PENZ: Mimicry in Zetherini its mimetic congeners, starting with P. lisarda that has large white markings on its wings. Note the correspondence between P. adelma forewing transverse bands and those of P. lisarda (indicated by arrow points in Fig. 6a, b, and lines in Fig. 6c, d), and that the latter has a complex hind wing pattern that mirrors that of its forewing. On the dorsal and ventral forewing of P. lisarda, the transverse band associated with pattern elements f photographs, variation not illustrated). This species shows an almost complete series of white eyespots on the fore and hind wings, which are larger on the ventral surface (Fig. 6a). White spots associated with parafocal elements i and j are present across the edges of both wings and both surfaces, being larger at the apex of the hind wing (Fig. 6a, c). The overall color pattern of P. adelma can be used to understand those of 107 Figure 7. Collection specimens showing hypothesized dorsal and ventral pattern elements, color-coded. Solid lines represent visible pattern elements, dotted lines represent the putative position of pattern elements that are not visible. Dorsal wing surface on the left-hand side, ventral on the right. a, Penthema darlisa male, no data, arrows indicate a forewing band likely associated with pattern elements f and g and c and d, plus hind wing bands associated with pattern elements f and g and parafocal elements i and j. b, P. formosanum female, Taiwan. c, P. formosanum male, Formosa, showing greatly reduced pale-colored bands (dark phenotype). See Material and Methods for museum deposition and locality data of collection specimens. TROP. LEPID. RES., 35(2): 99-116, 2025PENZ: Mimicry in Zetherini 114 western China), it seems unlikely that these mutually exclusive possibilities could be tested in the field. Penthema lisarda, P. darlisa, P. binghami and P. formosanum have pale stripes on a dark background, and the latter can have reduced stripes depending on the locality (Fig. 6, 7). In a recent publication (Penz 2017), I interpreted the outline of the pale bands are being outlined by serial pattern elements c-j while, more logically, they could be delimited longitudinally by venous and intervenous pattern elements (Fig 7d). It is nonetheless possible that, although they are not visible, some of the serial pattern elements are still involved in the development of the wing bands, that can only be determined by developmental studies. Regardless of the genetic and developmental pathways producing their color pattern (including blue iridescence in some geographical locations), these four Penthema species are convincing danaine mimics, and are large compared to their relatives in other mimetic Zetherini genera (e.g., Zethera; Fig. 1). Their color pattern has been fine-tuned locally by evolution as can be seen, for example, in P. lisarda within Thailand (see illustrations in Ek-Amnuay 2012). Fruhstorfer (1927) noted that Penthema are forest butterflies that fly fast, which could provide an extra level of protection against predation (see Quicke 2017). Penthema lisarda also has a propensity for visiting forest edges, traversing forest clearings and open or heavily disturbed habitats (Lien & Yuan 2003), which matches the habitat use of its models in the genus Ideopsis described by Ackery & Vane-Wright (1984:69-70). Callarge Callarge butterflies have narrow and elongate forewings, suggesting a slow flight and the possibility of good gliding ability (see Cespedes et al., 2015 and Stylman et al., 2020). While some individuals are almost completely pale (Fig. 3d), others have a striped pattern (not illustrated). Monastyrskii (2005) suggested that Calinaga butterflies are similar to Parantica aglea (Stoll, 1782) and this is in agreement with field observations by P. DeVries (pers. comm.). Igarashi & Fukuda (2000) listed Morus australis as hostplant of Calinaga buddah Moore, 1857 (now C. formosana Fruhstorfer, 1908) in Taiwan, and studies have demonstrated that members of the Moraceae produce secondary chemical compounds (e.g., Yang et al., 2014). The aposematic, red body of some Calinaga species suggests that these butterflies might possess some form of chemical defense (see images in https://www.inaturalist. org/taxa/358883-Calinaga/browse_photos, last accessed 23 May 2025). Igarashi & Fukuda (2000) also noted that, in high elevation Taiwan, Calinaga buddha flies together with the similarly colored and more broadly distributed Papilio epycides Hewitson, 1864 (as Chilasa epycides). Thus, Callarge butterflies might be members of an unstudied mimicry ring. Ethope Little is known about the natural history of Ethope butterflies. Fruhstorfer (1927, quoting Wood-Mason) noted that the non-mimetic E. himachala is a forest butterfly that rarely leaves its environment, an observation that was subsequently confirmed (Vane-Wright & Huggins, 1972 and references therein). Corbet & Pendlebury (1992) described the mimetic E. diademoides hislopi Corbet, 1948 as a forest butterfly as well. Among all mimetic Zetherini, Ethope shows a remarkable contrast from non-mimetic coloration in E. himachala, to mimetic convergence onto Euploea and papilionids in all other species. Vane-Wright & Huggins (1972) suggested that Ethope diademoides resembles Euploea core godarti Lucas, 1853 (Fig. 11c), the allopatric E. core core (Cramer, 1780), and also Papilio castor mehala Grose-Smith, 1886 (now P. mahadeva mehala) and Papilio clytia f. janus Fruhstorfer, 1901 (now P. clytia clytia Linnaeus, 1758). These authors further noted that Ethope noirei resembled Euploea kluge erichsoni C. Felder & R. Felder, 1865, the allopatric E. core distanti (Moore, 1882), Papilio castor mehala and Papilio clytia f. onpape Moore, 1878 (now P. clytia clytia Linnaeus, 1758). In this genus, a complex eyespot (with rings and pupil) is homologous with a solid pale marking (round or elongate) as can be seen in Fig. 8. Moreover, continuous, pale marginal lines are fragmented into discrete spots by venous and intervenous elements in mimetic taxa (e.g., contrast Fig. 8a and c). Curiously, E. himachala is the only species that has a large eyespot located near the costal margin of the ventral hind wing, suggesting that the eyespot is used for signaling in both sexes (see live butterfly photograph in Fig. 8g). Phylogenetic studies in progress indicate that E. himachala is the earliest diverging species of Ethope (D. Lohman, pers. comm.), pointing to the possibility that the non-mimetic himachala-morphotype might be the ancestral color pattern for Ethope. Moreover, the fact that mimicry is achieved by modifications of different pattern elements in Ethope and other members of the Zetherini, particularly the sister genus Zethera (Fig. 1), suggests that it might have evolved independently in this genus. Zethera Species of Zethera can be separated into two morphotypes, both of which converge on danaine models. The pimpleamorphotype includes four species that have evolved femalelimited mimicry. While females show a striped pattern similar to their danaine models (Fig. 9b, d, f; 10c), the non-mimetic males have transverse pale forewing bands that decrease in width from Z. pimplea to Z. musides, Z. thermaea, and Z. musa (Fig. 9a, c; 10a, b; 9e). In contrast, both sexes of the two incerta-morphotype species are mimetic (Fig. 10d-g), having highly developed pale wing bands that closely resemble the pale background color of their models. Some eyespots appear as dark areas with a central white marking in Z. incerta and Z. hestioides (Fig. 10f, g), suggesting a level of developmental conservatism in eyespot expression. Numerous putative models have been suggested for pimplea-morphotype females. Proposed models for Z. pimplea include: Euploea (Fruhstorfer, 1927); Danaus lotis (Cramer, 1779) (now D. melanippus lotis) (Fountaine, 1926 in VaneWright & Smiles, 1975); Euploea swainson (Godart, 1824), Danaus juventa (Cramer, 1777) (now Ideopsis juventa) (Fig. 11 b) and Euploea tobleri Semper, 1878 (Vane-Wright & Smiles, 1975). Models for Z. musa include: Euploea snelleni Moulton, 1921 (now E. crameri Lucas, 1853), Radena (now Ideopsis) and Euploea, with Z. musa mixta Fruhstorfer, 1899 resembling Elymnias ceryx, Boisduval, 1836 (Fruhstorfer, 1927). VaneTROP. LEPID. RES., 35(2): 99-116, 2025 PENZ: Mimicry in Zetherini ACKNOWLEDGMENTS Many thanks to museum curators who entrusted me with specimens: David Grimaldi at the American Museum of Natural History, NY; Blanca Huertas at The Natural History Museum, London, UK; Andrew Warren and Andrei Sourakov at Florida Museum of Natural History, McGuire Center for Lepidoptera, FL; Susan Borkin and Jeniffer Zaspel at the Milwaukee Public Museum, WI. Thanks also to all natural history photographers who posted images with precise localities online, in particular at the iNaturalist site. These images were essential for the examination of some of the species included in this study. I am grateful to Phil DeVries and David Lohman for suggestions and comments on the manuscript. Thanks also to Keith Willmot for editorial advice. I dedicate this study to Phil DeVries and all true naturalists—an increasingly rare breed of biologists who continue to document natural history and behavior in the field. LITERATURE CITED Wright & Smiles (1975) noted that on the Philippine Island of Mindanao, female Z. musa occur either as a juventa-like form, or a dark snelleni-like form, and considered Z. musides and Z. thermaea as having a juventa-like pattern. Igarashi & Fukuda (1997) found Z. pimplea to be common along forest edges, mountain trails or streams where the host plant is found (climbing bamboo, Dinochloa scandens). They noted that males are territorial and more visible than females, which are found in shady places and seem to be less active. These authors provided observations on the courtship behavior of Z. pimplea, where the male was seen flashing the dorsal side of its wings to a perched female. At a time in history when Charles Darwin and Alfred Russel Wallace had proposed competing hypotheses for the evolution of sexual dimorphism, it is important to recall that Thomas Belt (1874) suggested that mimetic females, if given a choice, might prefer males that retained the ‘primordial appearance’ of the species (Silberglied, 1984, see also Turner, 1978). The pimplea-morphotype species seems to fit Belt’s hypothesis, but confirmation will require choice-testing female mating preferences. Fruhstorfer (1927) and Vane-Wright & Smiles (1975) had differing opinions regarding the putative models for the two incerta-morphotype species. While Fruhstorfer (1927) considered Z. incerta very similar to Ideopsis vitrea (Blanchard, 1853), Vane-Wright & Smiles (1975) regarded Z. incerta as having only general resemblance to Ideopsis and Idea as it evolves towards mimicry. Further, Fruhstorfer (1927) assigned Ideopsis glaphyra Moore, 1883 (now I. gaura glaphyra) as a model for Z. hestioides, whereas Vane-Wright & Smiles (1975) suggested a resemblance to Idea leuconoe Erichson, 1834 (Fig. 11d), and Ideopsis gaura (Horsfield, 1829). Given that both sexes of Z. incerta and Z. hestioides converge on Ideopsis and Idea models, and that these species are very different from their congeners in the pimplea-morphotype, it is possible that mimicry evolved independently in these two morphotypes. Concluding remarks Through examination of many specimens and images, here I provide a more refined and detailed interpretation of color patterns and mimetic resemblance within Zetherini than what has been published previously (Penz, 2017). I also corrected previous errors of interpretation that resulted from incomplete sampling. Most importantly, the comparative study here allowed me to formulate working hypotheses that illuminate two independent pathways whereby non-mimetic color patterns could be modified by evolution to achieve mimetic resemblance in Zetherini. Although this paper focused on variation among species, it is clear that Zetherini species also vary geographically in color pattern. Of particular interest are the local, mimetic races that have evolved iridescence, not studied here. Intraspecific variation, in fact, highlights the potential for fine-tuning of mimetic convergence, and makes potential examples of imperfect mimicry examples all the more interesting. My work here was hampered by a lack of field experience with Zetherini species and their models, and I found the paucity of published observations on the behavior, mimicry and natural history of Zetherini butterflies to be astonishing. One may hope that this will change in the future. 115TROP. LEPID. RES., 35(2): 99-116, 2025PENZ: Mimicry in Zetherini Ackery, P. R., Vane-Wright, R. I. 1984. Milkweed Butterflies, Their Cladistics and Biology, being an account of the natural history of the Danainae, a subfamily of the Lepidoptera, Nymphalidae. London, British Museum (Natural History). 425 pp. Beccaloni, G. W., Viloria, A. L., Hall, S. K., Robinson, G. S. 2008. Catalogue of the hostplants of the Neotropical butterflies. Catálogo de las plantas huésped de las mariposas neotropicales. Zaragoza, Sociedad Entomológica Aragonesa. (Monografías del Tercer Milenio, Vol. 8). 536 pp., figs., 3 tabs. Belt, T. 1874. The naturalist in Nicaragua: A Narrative of a Residence at the Gold Mines of Chontales; Journeys in the Savannahs and Forests with Observations on Animals and Plants in Reference to the Theory of Evolution of Living Forms. London, John Murray. xvi + 403 pp., 4 pls., figs., 1 map. Benedick, S., Hill, J. K., Hamer, K. C., Mustaffa, N., Chey, V. K., Maryati, M. 2007. Butterfly dispersal and longevity in unlogged and selectively logged forest. Sepilol Bulletin 6:25-37. Cespedes, A., Penz, C. M., DeVries, P. J. 2015. Cruising the rain forest floor: butterfly wing shape evolution and gliding in ground effect. Journal of Animal Ecology 84: 808-816. Chazot, N., Condamine, F. L., Dudas, G., Peña, C., Kodandaramaiah, U., Matos-Maraví, P., Aduse-Poku, K., Elias, M., Warren, A., Lohman, D. J., Penz, C. M., DeVries, P., Fric, Z. F., Nylin, S., Müller, C., Kawahara, A. Y., Silva-Brandão, K. L., Lamas, Slamova, I. G., Zubek, A., OrtizAcevedo, E., Vila, R., Vane-Wright, R. I., Mullen, S. P., Jiggins, C. D., Wheat, C., Freitas, A. V. L., Wahlberg, N. 2021. Conserved ancestral tropical niche but different continental histories explain the latitudinal diversity gradient in brush-footed butterflies. Nature Communications 12: 5717. Chou, I. 1994 Monografia Rhopalocerorum Sinensium. Henan, Henan Scientific and Technological Publishing House. 854 pp. Christharina, S. G., Ikhwan, I. M., Fatimah, A. 2022. Effects of vertical gradient on the diversity and abundance of Nymphalidae in a Bornean rainforest. Serangga 27: 23-38. Clark, L., Bryant, B., Mezine, I. 2000. Bird aversive properties of methyl anthranilate, yucca, Xanthoxylum, and their mixtures. Journal of Chemical Ecology 26: 1219-1234. Clarke, C. A., Sheppard, P. M. 1959. The genetics of Papilio dardanus, Brown. I. Race cenea from South Africa. Genetics 44: 1347-1358. Clarke, C. A., Sheppard, P. M. 1960a. The evolution of mimicry in the butterfly Papilio dardanus. Heredity, 14: 163-173. Clarke, C. A., Sheppard, P. M. 1960b. Super-genes and mimicry. Heredity 14: 175-185. 116 TROP. LEPID. RES., 35(2): 99-116, 2025 PENZ: Mimicry in Zetherini Clarke, C. A., Sheppard, P. M. 1960c. The genetics of Papilio dardanus, Brown. II. Races dardanus, polytrophus, meseres, and tibullus. Genetics 45: 439-457. Clarke, C. A., Sheppard, P. M. 1960d. The genetics of Papilio dardanus, Brown. III. race antinorii from Abyssinia and race meriones from Madagascar. Genetics 45: 683-698. Corbet, A. S., Pendlebury, H. M. 1992. The Butterflies of the Malay Peninsula. 4th Edition, revised by J.N. Eliot. Kuala Lumpur, Malayan Natural History Society. 595 pp, 69 plates. D’Abrera, B. 1985. Butterflies of the Oriental Region. Part II. Nymphalidae, Satyridae & Amathusiidae. Melbourne, Hill House. 287 pp. Ek-Amnuay, P. 2012. Butterflies of Thailand. 2nd revised Edition. Bangkok, Baan Lae Suan Amarin Printing and Publishing. 943 pp. Fruhstorfer, H. 1927. 6. Family: Nymphalidae, pp 453-749. In: Seitz, A. (Ed.), The Macrolepidoptera of the World. Volume 9. The Rhopalocera of the Indo-Australian Faunal Region. Stuttgart, Alfted Kernen. Harada, M., Oshima, Y., Yoshida, Y., Wang, M. 2012. Report of surveys on the early stages of butterflies in the Nanling area (4). Lepidoptera Science 63: 165-174. Hegedus, M., DeVries, P. J., Penz, C. M. 2019. The influence of mimicry on wing shape evolution in the butterfly Papilio dardanus (Lepidoptera: Papilionidae). Annals of the Entomological Society of America 112: 33-43. Igarashi, S., Fukuda, H. 1997. The Life Histories of Asian Butterflies. Vol. 1. Tokyo, Tokay University Press. 550 pp. Igarashi, S., Fukuda, H. 2000. The Life Histories of Asian Butterflies. Vol. 2. Tokyo, Tokay University Press. 742 pp. Kawahara, A. Y., Storer, C., et al. 2023. A global phylogeny of butterflies reveals their evolutionary history, ancestral host and biogeographic origins. Nature Ecology and Evolution 7: 903-913. Kikuchi, D. W., Pfennig, D. W. 2013. Imperfect mimicry and the limits of natural selection. Quarterly Review of Biology 88: 297-315. Kronforst, M. R., Papa, R. 2015. The functional basis of wing patterning in Heliconius butterflies: the molecules behind mimicry. Genetics 200: 1-19. Kunte, K. 2009 The diversity and evolution of Batesian mimicry in Papilio swallowtail butterflies. Evolution 63: 2707-2716. Lien, V. V., Yuan, D. 2003. The differences of butterfly (Lepidoptera, Papilionoidea) communities in habitats with various degrees of disturbance and altitudes in tropical forests of Vietnam. Biodiversity & Conservation 12: 1099-1111. Linke, D., Elias, M., Klecová, I., Mappes, J., Matos-Maravi, P. 2022. Shape of evasive prey can be an important cue that triggers learning in avian predators. Frontiers in Ecology and Evolution 10: 910695. Miller, L. D. 1968. The higher classification, phylogeny and zoogeography of the Satyridae. Memoirs of the American Entomological Society 24: 1-174. Monastyrskii, A. 2005. Butterflies of Vietnam, Volume 1: Nymphalidae: Satyrinae. Thien Ngan Galaxy Co. Ltd., Hanoi. 162 pp, 35 pl. Nijhout, H. F. 1978. Wing pattern formation in Lepidoptera: a model. Journal of Experimental Zoology 206: 119-136. Nijhout, H. F. 1985. The developmental physiology of color patterns in Lepidoptera. Advances in Insect Physiology 18: 181-247. Nijhout, H. F. 1991. The Development and Evolution of Butterfly Wing Patterns. Washington, Smithsonian Institute Press. 297 pp. Nijhout, H. F., Wray, G. A. 1986. Homologies in the color patterns in the genus Charaxes (Lepidoptera: Nymphalidae). Biological Journal of the Linnean Society 28: 387-410. Peña, C., Wahlberg, N., Weingartner, E., Kodandaramaiah, U., Nylin, S., Freitas, A. V. L., Brower, A. V. 2006. Higher level phylogeny of Satyrinae butterflies (Lepidoptera: Nymphalidae) based on DNA sequence data. Molecular phylogenetics and Evolution 40: 29-49. Penz, C. M. 2017. Exploring color pattern diversification in early lineages of Satyrinae (Nymphalidae), pp. 21-37. In: Nijhout, H. F., Sekimura, T. (Eds.), Diversity and Evolution of Butterfly Wing Patterns, an Integrative Approach. Singapore, Springer Nature. Quicke, D. L. J. 2017. Mimicry, Crypsis, Masquerade and Other Adaptive Resemblances. West Sussex, John Wiley & Sons. 557 pp. Schulze, C. H., Linsenmair, K. E., Fiedler, K. 2001. Understorey versus canopy - patterns of vertical stratification and diversity among Lepidoptera in a Bornean rainforest. Plant Ecology 153: 133-152. Schwanwitsch, B. N. 1924. On the groundplan of wing-pattern in nymphalids and certain other families of rhopalocerous Lepidoptera. Proceedings of the Zoological Society of London ser. B 34: 509-528. Silberglied, R. E. 1984 Visual communication and sexual selection among butterflies, pp. 207-223. In: Vane-Wright, R. I., Ackery, P. R. (Eds.), The Biology of Butterflies. Princeton, Princeton University Press. 429 pp. Stylman, M., Penz, C., DeVries, P. J. 2020. Large hind wings enhance gliding performance in ground effect in a Neotropical butterfly (Lepidoptera: Nymphalidae). Annals of the Entomological Society of America 113: 15-22. Süffert, F. 1927. Zur vergleichende Analyse der Schmetterlingszeichnung. Biologisches Zentralblatt 47: 385-413. Tangah, J., Hill, J. K., Hamer, K. C., Dawood, M. M. 2004. Vertical distribution of fruit-feeding butterflies in Sabah, Borneo. Sepilok Bulletin 1: 17-27. Turner, J. R. G. 1978. Why male butterflies are non-mimetic: natural selection, sexual selection, group selection, modification and sieving. Biological Journal of the Linnean Society 10: 385-432. Vane-Wright R. I., Huggins, C. 1972. The superspecies Ethope himachala (Moore), and the identity of Zethera noirei Janet (Lepidoptera, Nymphalidae, Satyrinae). Journal of Entomology Series B, 41: 1-22. Vane-Wright R. I., Smiles, R. L. 1975. The species of the genus Zethera Felder (Lepidoptera, Nymphalidae, Satyrinae). Journal of Entomology Series B, 44: 81-100. Van Belleghem, S. M., Alicea Roman, P. A., Carbia Gutierrez, H., Counterman, B. A., Papa, R. 2020. Perfect mimicry between Heliconius butterflies is constrained by genetics and development. Proceedings of the Royal Society B 287: 20201267. Wahlberg, N., Leneveu, J., Kodandaramaiah, U., Peña, C., Nylin, S., Freitas, A. V. L., Brower, A. V. Z. 2009. Nymphalid butterflies diversify following near demise at the Cretaceous/Tertiary boundary. Proceedings of the Royal Society, Series B, Biological Sciences 276: 4295-4302. Widhiono, I. 2015. Diversity of butterflies in four different forest types in Mount Slamet, Central Java, Indonesia. Biodiversitas 16: 196-204. Wolfe, K. V. 1996. Notes on the early stages of Zethera musides (Lepidoptera: Nymphalidae: Satyrinae). Tropical Lepidoptera Research 7: 147-150. Wootton, R. J. 1979. Function, homology and terminology in insect wings. Systematic Entomology 4: 81-93. Yang, M., Zhang, Y. 2015. Phylogenetic utility of ribosomal genes for reconstructing the phylogeny of five Chinese satyrine tribes. Zookeys 488: 105-120. Yang, Y., Yang, X., Xu, B., Zeng, G., Tan, J., He, X., Hu, C., Zhou, Y. 2014. Chemical constituents of Morus alba L. and their inhibitory effect on 3T3L1 preadipocyte proliferation and differentiation. Fitoterapia 98: 222-227.