A new species of spectacular spider wasp mimic from Thailand is the first representative of the genus Melanosphecia Le Cerf 1916 (Lepidoptera: Sesiidae: Osminiini) to be filmed in the wild

Abstract

A metallic blue, new species of clearwing moth from Thailand is described and shown on video. With its spectacular colouration, long hind legs and an incredible illusion of a wasp-waist, complemented by behavioural imitations, this sesiid is a striking spider wasp mimic. Notes on possible mimicry models, behaviour and conditions of occurrence are given. COI DNA barcode sequence is provided. This is the first country record of Melanosphecia Le Cerf 1916 for Thailand and the first representative of this genus to be filmed in its natural habitat.

A Vivid Orange New Genus and Species of Braconid-Mimicking Clearwing Moth (Lepidoptera: Sesiidae) Found Puddling on Plecoptera Exuviae

“…nov. has long functional hind legs which it uses for locomotion, clinging onto rocks (Video S1 TC 01:49-01:58) or, along with the fore and mid legs, for taking off and landing (Video S1 TC 01:59-02:22; 02:41-02:43). The white colouration of the hind tibia matches the white patches on the sides of the sesiid's abdomen (Figure 1c), which in flight gives an impression of a "wasp waist" 02:34-02:44), similarly, although not as spectacularly as in Melanosphecia paolo Skowron Volponi, 2019. In flight, the skinny legs of A. piotrii sp. nov. give it a wasp-like appearance, in contrast to Aschistophleps argentifasciata Skowron Volponi, 2018 [15] or Heterosphecia pahangensis Skowron, 2015 [18], in which their strongly tufted legs hanging downwards in flight resemble bees.…”

“…The process of sucking up liquids from moist substrate, termed puddling or mud-puddling, has been observed and described by the author for many sesiids [6,8,15,18]. Most of the observed species seem to have been puddling for salt and would lick surfaces where salt solutions were poured [18] or even drink sweat directly from the author's skin.…”

“…This new genus is most similar to Melanosphecia Le Cerf, 1916, Aschistophleps Hampson, 1893, Heterosphecia Le Cerf, 1916 and Akaisphecia Gorbunov & Arita, 1995 but can be easily distinguished from all these genera by the absence of conspicuous hind leg tufts of elongated scales (Aurantiosphecia gen. nov. has long, wasp-like, smooth-scaled legs with only some moderately elongated scales on the distal part of the hind tibiae), overall body colouration and by the configuration of male genitalia, especially the shape of uncus and valvae. It can be additionally distinguished from Aschistophleps by the entirely, or almost entirely, opaque forewings (entirely or with at least some transparency in the anterior, posterior and exterior transparent areas in Aschistophleps [3,14,15]), from Heterosphecia by opaque forewings, bright orange colouration and the more slender wasp-like body with long hind legs (in comparison to the robust, bee-like representatives of Heterosphecia [1,5]), from Melanosphecia by the smaller and less robust body and overall colouration (metallic/steel blue colours in Melanosphecia [6,16]) and from Akaisphecia by the absence of a filiform appendix at the tip of the abdomen [4] and opaque parts of the fore-and hindwings. The male genitalia most closely resemble those of Chamanthedon Le Cerf, 1916, especially the distinct long and narrow uncus, but Aurantiosphecia gen. nov. differs from this genus significantly: in a functional proboscis; wing venation (veins R 4 and R 5 are long and stalked in Chamanthedon, vein R 5 is absent in Aurantiosphecia gen. nov.); opaque forewings; orange colouration of various body parts; as well as in the shape of valvae and saccus (which are more rounded in the comparable genus, see Figures 10 and 11 in [17]).…”

“…For immediate in-the-field taxonomic placement, apart from the presence or absence of conspicuous hind leg tufts, one could propose establishing a novel genus level diagnostic feature: the position of forewings in a typical resting posture. Aurantiosphecia gen. nov. and Melanosphecia [6] rest with forewing tips overlapping, whereas the representatives of all other Oriental Osminiini genera keep their wings folded back against their body separately, not overlapping ( Figure 2).…”

“…Oriental clearwing moths of the tribe Osminiini have been studied from the late XIX century [1], through the early [2] and late [3,4] XX century, until the 2000s [5,6]. These studies have shown that representatives of this tribe are highly diverse in their external and genital morphology, as well as, as indicated in more recent studies, in the model species they mimic, which range from stingless bees [7], through potter [8] and spider wasps [6], to pyrrhocorid bugs [9]. Almost all known species, however, have been described based on pinned specimens only.…”