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| Scarlata nirvana Skowron Volponi, 2022 |
Abstract
A stunning scarlet-coloured clearwing moth was found mud-puddling on a rainforest river bank in Malaysia and is described herein as a new genus and species, Scarlata nirvana gen. et sp. nov.. This sesiid seems to be a rare case of a mimic of an assassin bug (Hemiptera: Reduviidae) in a family otherwise known for hymenopteran mimicry. A high-quality video of the moth’s behaviour in its habitat is provided. Studies of the collections of the Natural History Museum in London revealed another member of the new genus, S. guichardii sp. nov. A third species, S. ignisquamulata Kallies, 2018 comb. nov. is transferred to Scarlata gen. nov. from the genus Aschistophleps Hampson, 1892. The second new lineage from Malaysia described here, Malayomelittia gen. nov., includes two species, Malayomelittia pahangensis Skowron, 2015 comb. nov. and M. ruficrista Rothschild, 1912 comb. nov. Additionally, Heterosphecia bantanakai Arita & Gorbunov, 2000 is placed as a junior synonym of H. hyaloptera Hampson, 1919 syn. nov. Morphological descriptions, remarks on behaviour, conditions of occurrence and a discussion about potential mimicry models are included. All new taxa are figured, including images of male genitalia.
Keywords: Assassin bug, mimicry, Malaysia, puddling, new taxa
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| (a) Scarlata nirvana gen. et sp. nov. holotype male; (b) S. guichardii gen. et sp. nov. holotype male; (c) Malayomelittia ruficrista comb. nov. holotype female; (d). M. ruficrista male NHMUK10605228. |
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| Details of the head and outline of the eye of: (a) Malayomelittia pahangensis comb. nov.; (b) Scarlata nirvana gen. et sp. nov. Note differences in the shape of the eye and in scaling of labial palp apically. |
Malayomelittia Skowron Volponi gen. nov.
Type species: Heterosphecia pahangensis Skowron, 2015.
Composition: Only two known species belong to this newly described genus:
Malayomelittia pahangensis (Skowron, 2015), comb. nov.
and Malayomelittia ruficrista (Rothschild, 1912), comb. nov.
Etymology. The name derives from Malaysia, the country of origin of representatives of this genus, and the Greek “melitta” (bee), due to the type species’ splendid mimicry of Trigona bees. The gender is feminine.
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| Scarlata nirvana gen. et sp. nov. exposing its hind leg tufts in a common feeding position of this species. |
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| Scarlata nirvana gen. et sp. nov. in a typical resting position. |
Scarlata Skowron Volponi gen. nov.
Type species: Scarlata nirvana Skowron Volponi sp. nov.
Small (wingspan 14–17 mm) and slender clearwing moths with scarlet coloured, conspicuous hindleg tufts of elongated scales. Antennae simple and clavate, frons covered with smooth scales, labial palpi mostly smooth-scaled with narrow elongated scales at tip and wide, slightly erected scales at base. Thorax and abdomen covered with smooth scales, either scarlet or black. Wings mostly transparent with broad black fore- and hindwing discal spots and margins. Male genitalia morphology distinct from other Osminiini: uncus with very short sclerotized setae on margins, similar setae forming a small patch or row at tip of valva, valva folded inwards subapically on coastal margin.
Differential diagnosis:
Superficially similar to Malayomelittia and Aschistophleps but can be differentiated by the morphology of the male genitalia, the shape of the eye, scaling of labial palps (more hair-like scales apically in Malayomelittia), broader hindwing discal spot and the structure of the hindleg tuft: in Scarlata, the hair-like scales are strongly elongated on the inner margin, moving towards the dorsal side there is a narrow groove covered with shorter scales followed by a ridge of elongated scales dorsally, the tuft of elongated scales continues onto the proximal half of the 1st tarsomere only on the inner margin, on the hindleg outer side the scales are elongated only on the tibia, the 1st tarsomere is dorsally and externally smooth-scaled. Scarlata does not have a tuft of hair-scales on the midleg. In Malayomelittia the hindleg tuft is made of almost equally elongated scales dorsally and on both inner and outer sides of tibia and entire 1st tarsomere. Aschistophleps has a tuft of hairs on the midleg tibia and two small tufts on the hind leg which allows for the immediate differentiation from closely related genera. Overall, the hindleg tufts of the genera Scarlata, Malayomelittia and Heterosphecia are very conspicuous, made of dense, elongated scales. In the slender-bodied species of Pyrophleps, these tufts are much less impressive and scales less elongated.
In the field, representatives of the genus Scarlata can be differentiated from Malayomelittia and Aschistophleps by their posture, especially different ways of exposing the hind leg tufts. Scarlata species often spread out their wings (Figure 2; Suppl. video TC 02:50–03:05), showing the bright red hind legs with tarsi curled up, not using them much to move around. Malayomelittia, when puddling, always keeps its wings folded back against the body and rises the hind legs upwards, often moving them slightly to expose the conspicuous tufts (see Suppl. video in Skowron et al. 2015), but never uses them to walk, whereas Aschistophleps, keeping its wings folded against its body and hind legs on the outer side of the wings, uses the hind legs actively for locomotion. Pyrophleps species do not expose hindleg tufts significantly but keep the hind legs close to their slender abdomens and most of the time concealed beneath the wings.
From the similarly-coloured species of Akaisphecia Gorbunov and Arita (1995), Scarlata can be distinguished by the absence of a filiform appendix on the abdomen, structure of hind leg tufts, well-developed forewing transparent areas and morphology of male genitalia.
Composition: This genus consists of three species:
S. ignisquamulata Kallies, 2018 comb. nov.;
S. nirvana Skowron Volponi sp. nov.
and S. guichardii Skowron Volponi sp. nov.
Scarlata nirvana sp. nov.
Etymology: This species is named after the Nirvana Asia Group, who co-financed the expedition to Malaysia during which this new species was discovered.
Marta Skowron Volponi. 2022. Hidden Jewels of Malaysia: Two New Genera and Species of remarkable Clearwing Moths (Lepidoptera: Sesiidae: Osminiini). The European Zoological Journal. 89(1); 579-589. DOI: 10.1080/24750263.2022.2061613
