Specimens from Peru

Thirteen specimens collected in Loreto and Madre de Dios, respectively, deposited in MUSM and SNSB (Fig. 9A–M, Table 2: PL01–PL04, PM01–PM09), share basic characters with V. kiesela from Panguana and add to their diversity in appearance. PM08 and PM09 have a white (not yellow) hindwing pattern, PM09 does not clearly show the typical bulge on the underside of the hindwing, and the genitalia show some variation. In the specimens from Loreto (PL01–PL04), the forewing oblique band extends to vein 1A+2A and their genitalia vary slightly: the saccus is rounded, the anterior part of the tegumen is narrower, and the leaflets are more arched, while in V. kiesela, the saccus is somewhat truncated, the tegumen is wider, and the valves less arched. Nevertheless, all were caught at PA-baits and DNA barcodes of selected specimens fit with V. kiesela (Fig. 13). The branching within BIN BOLD:ADO9441 does not reflect the origins of the specimens, rather those from Panguana and Madre de Dios are interspersed; the specimens from Loreto are separated by 1.3% from the main V. kiesela cluster.

Specimens from French Guiana

From French Guiana we have seen three specimens (Fig. 10; Table 2: FG01–FG03), also collected in the daytime at PA-baits, which are very similar to the holotype of V. kiesela but do not show variation. In comparison with V. kiesela, on the forewings the oblique yellow band ends at vein 1A+2A not at CuA₂. The basal yellow patch is almost absent, reduced to a small elongated patch at the base of anal border and a blurred elongated triangle below costa, this triangle is fused with the oblique band which is sharply bent at right angle near tornus. On the hindwings, the basal yellow area is reduced due to the presence of a blackish band along the costa and along the anal border which is narrowly yellow on margin. The head, patagia, tegulae, and thorax are markedly darker. The venter is not pure white but interspersed with yellow hairs. On the underside of the forewings the anal border is blackish, compared with yellowish white in kiesela. On the underside of the hindwings, the basal area is not pure yellow, but there are two streaks of blackish scales, one along the anal border and one below the costa, near the base. Forewing length ca. 14 mm. Female unknown.

The genitalia of FG02 (Fig. 10D) exhibit small differenes to V. kiesela: in ventral view, the valvae appear narrower and smoother. In lateral view the uncus is widened after the middle not before. The juxta is wider at base, shorter, and much more constricted in the middle. In lateral view, the last third of the valvae seems different, the phallus is more sinuate, and the sclerotized area has a different shape. DNA barcodes of FG01–FG03 form a subcluster of Vanewrightia (BIN BOLD:ADO9441), with a barcode gap of 1.0–1.1% to the main V. kiesela cluster and 1.8% to specimens from LO (Fig. 13).

Specimens from the NHMUK

In the NHMUK, several individuals (for examples see Fig. 11, Table 2: VE01–VE05, BR01–BR06) resembling one or the other variants of V. kiesela from Peru were found; they either carry no name label or are treated as Epidesma obliqua (Schaus, 1898). Without dissection or sequencing eleven specimens can be allocated to Vanewrightia and divided into three groups: group A contains five specimens (Fig. 11A–E, Table 2: VE01–VE05) from Venezuela (Caura Valley), group B contains five specimens (see Fig. 11F–K, Table 2: BR01–BR05) from Brazil (Pará and Rondonia), and group C with one specimen (Fig. 11L, Table 2: BR06), also from Brazil (Amazonas).

Group A is characterized by a deep oblique yellow band on the forewing upperside and a yellow central patch on hindwings displaying the characteristic bulge around vein M2. On the forewing underside, the oblique band is slightly longer and wider and there is a whitish streak basally, whereas in one variant on the hindwing the basal area is large, milky-white, with the characteristic bulge. The species is variable and on the hindwing underside the basal area can be white only in the anal half or the milky-white area is largely suffused with dark scales. On the hindwing upperside, the yellow basal area can be reduced to a small patch or totally absent.

Group B is more similar to the French Guiana entity with a longer and wider oblique yellow band and a basal area with yellowish lines on veins. The yellow patch on the hindwing is largely bordered by black but displays the characteristic bulge. On the underside, on forewings, the basal area is yellow separated from the oblique yellow band by a large black band, and on hindwings, there is a large yellow area bordered by black from apex to near tornus, sometimes with faint blackish streaks.

Fig. 10.

(A–C) Male specimens of Vanewrightia gen. nov., collected at pyrrolizidine alkaloid baits in the daytime in French Guiana (courtesy of Robert Vande Merghel); left upperside, right underside. (D) Male genitalia of FG02; dorsal, ventral, phallus from left to right. Details on specimen codes in Table 2. Scale bars = (A–C) 1 cm, (D) 1 mm.

Fig. 11.

Examples of unnamed moths housed in the NHMUK and showing characters typical for Vanewrightia gen. nov.; see text; left upperside, right underside. (A–E) Group A (D is mirrored because the specimen misses the left forewing). (F–K) Group B. (L) Group C. Details on specimen codes inTable 2. Photographs by Trustees of the Natural History Museum, London. Scale bar = 1 cm.

Group C seems divergent with respect to the anal border area of the hindwing underside, which is largely suffused with white.

Fig. 12.

Selection of species of Epidesma to demonstrate their variation and similarity with respect to wing pattern versus male genitalia. (A–F) Epidesma aurimacula syn. nov. from Panguana/Peru (A, B), from French Guiana (C, D), from Bolivia (E), from Venezuela (F). (G) E. klagesi. (H) E. ursula from French Guiana. (I) E. sp. nr ursula from Costa Rica. (K) E. sp. nr klagesi from Costa Rica. (L) E. nr crameri from Peru. (M) Recently transferred from Epidesma (Laguerre 2019): Aphymolis similis; left upperside, right underside; genitalia dorsal, ventral, phallus from left to right. Scale bars = 1 cm for moths, 1 mm for genitalia. See also Fig. 4.

Fig. 13.

Neighbor-joining distance tree of 27 COI sequences of Vanewrightia gen. nov. and 38 of its neighbors from BOLDSYSTEMS (2019) with BIN BOLD codes. Distances (normalized to 1) are given below each branch (omitted if <0.002) and bootstrap supports above each branch (in bold, only if >70%) obtained with MEGA7 (Kumar et al. 2016). For Vanewrightia, the collection sites are highlighted by colors. Scale bar = 1%.

Similarity of Vanewrightia with Unrelated Taxa

Identifying Vanewrightia species based on their appearance is doubly challenging: on the one hand, because of the great intraspecific variation a demarcation of the species has much uncertainty, on the other hand, because they can easily be confused with very similar-looking species in the same moth community (see Figs. 2, 4, and 12). Examining a large collection such as the NHMUK greatly increases the challenge and the confusion: not only are there many Arctiinae but also Notodontidae (Dioptinae) and others with the same general wing pattern; several Erbessa (Dioptini) species exhibit an angled hindwing margin (see Miller 2009: plate 4), a main diagnostic character of Vanewrightia. Specimen BR03 (Fig. 11H) was misidentified by Moss as Myonia desmotrichoides Hering, 1925, a species later put into Erbessa and for a long time considered likely to be an arctiine (Miller 2009: 149).

Even more striking is the similarity of some Vanewrightia variants (Figs. 2Q and 9M) with Erbessa tegyroides Miller, 2009: 169, plate 4, a peculiar notodontid (Dioptini) that is also day-active, in which the males have yellow hindwings and the females white hindwings. According to Miller (2009: 869), it forms a mimicry ring with Proutiella tegyra Druce, 1899 (Fig. 4K), Ephialtias abrupta Hübner, [1809] (Josiini), Ordishia klagesi (Rothschild, 1909; Fig. 4D; Arctiinae), and a diurnal pyralid, Nachaba sp. (Chrysauginae); P. esoterica (Prout, 1918; Fig. 4F) would also fit (Miller 2009: 684).

Chamaelimnas briola Bates, 1868 (Riodinidae: Riodininae: Riodinini) requires particular consideration. This butterfly occurs in a variety of forms (Fig. 14), is discussed as a mimic of some moths (Seitz 1916), and demonstrates a striking parallel to Vanewrightia. However, it is not that the similarity is particularly accurate, rather Vanewrightia and Chamaelimnas appear to show variation in the very same pattern elements (see above) although instead of a yellow forewing band Chamaelimnas has a more or less yellow dot. In Panguana, a habitat of Vanewrightia where no specific search for Chamaelimnas has yet been undertaken, four variants of C. briola have been collected. Seitz (1924: 655) commented on the genus: ‘The shape of the yellow spots differs at every habitat and is so characteristic that one can exactly see from it, whether a specimen of the genus has been captured on the Corcovado near Rio, or in the Serra do Mar near Santos, in Espiritu Santo or in Blumenau’. This means that C. briola has different patterns in different populations and is comparable with the many cases of geographic variation within a species. However, Stichel (1928) has heavily (and sarcastically) opposed this statement. If Stichel (1928) is right, Chamaelimnas would―just like Vanewrightia―show high variation within a population. This issue, unfortunately, has not been properly addressed in the past 90 yr and Chamaelimnas remains an understudied taxon, too. However, from Ecuador there is evidence that different forms do co-occur (Fig. 14).

Other, equally understudied taxa also fit into the discussion: species of Seirocastnia (Agaristinae) and Cyllopoda (Geometridae) show a similar pattern to some variants of Vanewrightia and to Chamaelimnas, perhaps also exhibiting intraspecific variation but not yet studied.

Pattern-forming processes and intraspecific differences in wing pattern are gaining considerable interest in Lepidoptera (see, e.g., Nijhout 2003a,b; Joron et al. 2006; Nadeau 2016; Gawne and Nijhout 2019). Both Vanewrightia and Chamaelimnas appear to be potentially interesting taxa for the study of evolutionary developmental biology.

‘Mimetic’ Relationships

Here is not the place to discuss mimicry in Arctiinae in any detail. However, a few remarks need to be made. Without a doubt, some Arctiinae are obviously and quite plausibly involved in mimicry, including Chetone (Pericopina) and Heliconiinae (Elias and Joron 2015) or wasp-like Ctenuchina and Hymenoptera (Vespidae; Simmons 2009; Boppré et al. 2017 and references therein); these examples to not permit or suggest much generalization. For most species with similarities to unrelated taxa, plausibility can be challenged; where mimicry has been suggested for Arctiinae, it is usually unknown which is profitable or unprofitable prey, respectively, and who or what is the selecting agent. Neither has it been adequately demonstrated that putative models and (co-)mimics live together, or which characters are relevant for antagonists. In an ecological context, all can be very different to those aspects that taxonomists perceive or consider.

For many species assumed to form mimicry rings, one also has to consider if they simply protect themselves via crypsis or masquerade (see Boppré et al. 2017: table 2). Perhaps, an oblique yellow band, which has convergently evolved in many moths and butterflies worldwide, is a cryptic or disruptive pattern, making both day- as well as night-active Lepidoptera difficult to detect when at rest. Note that while many of the taxonomically diverse species discussed here on close inspection exhibit some differentiating characters or not, when the moths sit at rest, most are invisible. Note that to a predator the only visible pattern element is a yellow band on a dark brown background (Fig. 15). Similarities observed in moths differ from classical cases of mimicry and seem more complex than the famous textbook examples on butterflies. In either case, the great similarities of taxa often mislead taxonomist and are an issue in need for investigation by ecologists dealing with prey–predator relationships. Polymorphism and variation, particularly in aposematic species, add to the complexity (see Briolat et al. 2019).

Conclusions

In view of the striking variation within V. kiesela and a limited number of specimens, the message of our paper, unfortunately, is not and cannot be to clarify fully the systematics of this taxon and its relatives but to make field-collectors as well as museum curators aware of the phenomenon and interesting questions behind it. This also holds true for all Epidesma.

Baiting with PAs in Latin America is not only rewarding with respect to Vanewrightia and Epidesma—with this method we are finding several other new species in the Neotropics (Grados 2004; M.L. and M.B., unpublished data) as we did previously in the Old World (e.g., Häuser and Boppré 1997; Scherer and Boppré 1997; see Boppré and Monzón 2020).

Fig. 14.

Variants of Chamaelimnas briola Bates, 1868 (Riodinidae: Riodininae: Riodinini) from Sangay National Park, Ecuador, sorted according to the amount of yellow on the upperside wings (reproduced with permission from Petit 2019; re-arranged). Compare the variation in pattern elements of this butterfly with those of Vanewrightia (Figs. 2, 9, 10, and 11). Natural size 29–33 mm.

Fig. 15.

Small selection of moths from Panguana with an oblique forewing band (see Fig. 4), photographed in resting position; sizes not adjusted. (A) Ordishia rutilus. (B) Loxozona lanceolata. (C) Epidesma crameri. (D) Euchlaenidia ockendeni Rothschild, 1910. (E) E. aurimacula. (F) Proutiella esoterica.

Seeking rare moths of uncertain identity and changing the status of species of which only a single specimen is available may seem a bit insane in times of global biodiversity loss on an immense scale. However, the little we know about both Vanewrightia and Epidesma s.l. teaches us not only a lesson on intraspecific wing pattern variation but also on 1) the need and importance of natural history studies (cf. Ricklefs 2012), although currently not popular (Ríos-Saldaña et al. 2018); 2) the need for more (amateur) entomologists in Latin America, in particular those who look for early instars and rear and breed moths and who employ not only lights for collecting (Grados et al. 2015; Boppré and Monzón 2020); 3) the need to investigate entire moth communities and their biologies instead of concentrating on α-taxonomy; 4) morphospecies should not be described on the basis of single specimens (see Dayrat 2005; Lim et al. 2012); 5) specimen labels should include the circumstances of collection (at light, at bait, at flower, during the day/night, etc.; see Ferro and Summerlin 2019) to foster and facilitate integrative taxonomy (Schlick-Steiner et al. 2010); 6) characters on the underside can be important for identification; unfortunately, many books and internet resources only illustrate uppersides of moths; and 7) variation in male genitalia is a subject that requires much more attention. Male genitalia in insects are generally considered to show no or low within-species variability (due to the lock-and-key hypothesis; see Shapiro and Porter 1989). If at all, most often genitalia preparations for descriptions are made from a single specimen only. There are, however, reports of great intraspecific variation in lepidopteran genitalia (Mutanen et al. 2006; Gilligan and Wenzel 2008, and references therein), suggesting the need to study a series of specimens; for Arctiinae, genitalic variation is as yet uninvestigated.

Hopefully, this report will stimulate researchers in Latin America to look out for Vanewrightia (and on Chamaelimnas and others); quite possibly, there are areas and/or times when their abundance is high. We believe that there are some more specimens hidden in collections, and more will be found when baiting with PAs in late afternoons. Any additional specimen of Vanewrightia s.l. will be important for better understanding the striking intraspecific variation of this taxon. We are also most curious to see females of Vanewrightia―are they as variable as the males? Or do they have a completely different appearance?