New and recent records of hawk moths (Lepidoptera: Sphingidae) from Seychelles, with a description of a new insular subspecies

In this study, we examine a recent sample containing two hawk moth species (Lepidoptera: Sphingidae) from Praslin and Mahé, Seychelles. It was widely accepted that the hawk moth species Temnora peckoveri (Butler, 1876) has a disjunctive range covering Madagascar and the Inner Seychelles. However, the Seychelles population of what was thought to be Temnora peckoveri shares a set of diagnostic morphological differences from both this species and T. fumosa (Walker, 1856) in the male genitalia structure. In particular, it remotely resembles Temnora fumosa based on the structure of aedeagus but differs from T. fumosa and T. peckoveri with respect to the harpe shape. Based on this evidence, we describe Temnora fumosa seychellensis Bolotov & Spitsyn ssp. nov. as a subspecies with restricted range,  being endemic to the Inner Seychelles. The range of this subspecies covers Praslin (first record), Mahé, Silhouette, La Digue, Cousine, and Denis. Additionally, we report on recent occurrences of Agrius convolvuli (Linnaeus, 1758) from Praslin (second record) and Mahé. The adult moths were recorded feeding on inflorescences of Dracaena reflexa var. angustifolia Baker (Asparagaceae) for the first time. Finally, we present a complete list of Temnora fumosa seychellensis ssp. nov. and Agrius convolvuli occurrences from Seychelles.


Introduction
The Lepidoptera fauna of Seychelles is rather well known, with the maximum species richness on the country's largest island, Mahé (Legrand 1966;Gerlach and Matyot 2006;Lawrence 2014). However, a growing body of faunal surveys revealed that the number of Lepidoptera species on smaller granitic islands such as Praslin and La Digue was largely underestimated (Bolotov et al. 2014b(Bolotov et al. , 2015Lawrence 2015;Bippus 2016;De Prins and Mazzei 2016). Several endemic species described from Mahé were recorded recently from Praslin (Bolotov et al. 2014a(Bolotov et al. , 2016Bippus 2016). Furthermore, alien Lepidoptera species arriving to Mahé could likely spread over surrounding islands of the archipelago (Kolosova and Bolotov 2020).
The hawk moths (Sphingidae) are among the largest and most attractive insects in Seychelles (Matyot 2005). The fauna of this family on the granitic and coralline islands was studied in detail, although the regional distribution patterns within the archipelago need further research (Legrand 1966;Matyot 2005;Gerlach and Matyot 2006;Lawrence and Henwood 2009). Moreover, there was a recent record of a hawk moth species new to the fauna of Seychelles (Lawrence 2015). In total, the hawk moth fauna of Seychelles contains 15 species, while the granitic islands house 10 species in this group (Gerlach and Matyot 2006;Lawrence 2015).  Table 1 for detail) In this correspondence, we report on records of two hawk moth taxa, Temnora fumosa seychellensis ssp. nov. and Agrius convolvuli (Linnaeus, 1758), from the Inner Seychelles. The discovery of the first taxon was completely unexpected. It shares clear differences from Temnora peckoveri (Butler, 1876) and T. fumosa fumosa (Walker, 1856) in the male genitalia structure. This new insular subspecies is described here.

Materials and methods
The pinned specimens were studied in the RMBH -Russian Museum of Biodiversity Hotspots, N. Laverov Federal Center for Integrated Arctic Research of the Ural Branch of the Russian Academy of Sciences, Arkhangelsk, Russia. The genitalia were dissected, mounted on temporary glass slides with 70% ethanol and photographed using a research stereomicroscope (AXIO Zoom.V16, Carl Zeiss, Germany). The genitalia are kept in a micro-tube with glycerin pinned to the specimen. Images of specimens were taken with a Canon EOS 7D camera (Canon Inc., Tokyo, Japan). Available occurrences of the two target species on the islands of Seychelles were collected from published sources, and the localities were georeferenced using Google Earth v. 9.129.0.1 (Tables 1-2).     Fig. 2A-B).
Diagnosis. The new subspecies could be distinguished from Temnora fumosa fumosa based on the structure of harpe (Figs. 3-4). T. fumosa fumosa shares a long, narrow, sickle-shaped harpe (Fig. 4D). In contrast, the new subspecies shares a much wider and shorter, straight harpe with an upcurved, claw-like end (Fig. 4E). Furthermore, both the new subspecies and T. fumosa fumosa differ from T. peckoveri by the lack of a strong long tooth at the distal end of aedeagus (compare Fig. 4A, 4B, and 4C). The harpe of the new subspecies is much broader proximally and narrower distally compared with that of T. peckoveri (Fig. 4F).  (Fig. 2): Wingspan 50 mm, forewing length 25 mm. Eye, antenna, and head dark olive. Labial palpus somewhat elongated (approximately two eye's diameter), dark olive dorsally, light grey ventrally. Thorax, patagium, and tegula dark olive. Legs light grey, slightly darkened dorsally. Forewing outer margin with deep, rounded excavation below apex. Forewing upperside dark olive with broad darker brown antemedial and postmedial bands; postmarginal area greyish olive, with a dark, inconspicuous zig zag subterminal band and a small white spot at costa subterminally. Small white discal spot present. Forewing underside dark olive, with unclear blackish or dark brown triangular patch from the base to the discal area. Hindwing upperside uniformly dark brown with long dark olive scales. Hindwing underside dark olive, with a row of submarginal black spots and a dark patch between veins CuA1 and CuA2. Abdomen dark olive. Male genitalia (Figs 3-4): Tegumen very broad, strongly sclerotized. Uncus bifurcated apically; uncus and gnathos form a typical macroglossine "bird-beak" structure. Valva slightly elongated, rounded apically. Harpe broad, straight, upcurved and pointed near the distal end. The base of harpe very broad. Aedeagus long, straight, with an oblique densely serrated ridge. Vesica long, with a bunch of ultra-elongate spines.

Description. Male
Female: Not examined.
Etymology. This subspecies is named after the Seychelles Archipelago, where it is distributed. Distribution. Endemic to the Inner Seychelles (Fig. 1). So far it is known to occur on the granitic islands of Mahé (De Joannis 1894), Silhouette (Fryer 1912), La Digue (De Prins and Mazzei 2016), Cousine (Lawrence and Henwood 2009), and Praslin (this study), and on the coralline island of Denis (Matyot 2005 (Fig. 5). However, the moth most likely came from the edge of surrounding mixed secondary forest dominated by various endemic palms and cinnamon trees. This forest patch also houses Indian Mulberry Morinda citrifolia L. (Rubiaceae), a host plant of this taxon on the Inner Seychelles (Matyot 2005).

Conservation.
The new subspecies appears to be Endangered [EN B1, B2 + aс(iii)]. It has an estimated extent of occurrence (EOO) of 330 km 2 and an area of occupancy (AOO) of 174 km 2 (Gerlach and Matyot 2006). Furthermore, it has a highly fragmented range, is known to occur on a few islands, and shares extreme fluctuations in number of subpopulations. Previously, this subspecies was accessed as Vulnerable [VU B1abiii,B2abiii] in Seychelles but that assessment was based on its earlier treatment as a population of the more widespread taxon Temnora peckoveri (see Gerlach and Matyot 2006 fig. 4 [Praslin]. Table 2.
Comments. Second record from Praslin. In contrast, it frequently occurs on Mahé (Matyot 2005; this study).

Discussion
Initially, the Seychelles Temnora population was identified as belonging to the Madagascar species T. peckoveri using external diagnostic features alone (De Joannis 1894;Fryer 1912;Legrand 1966). Neither those earlier scholars nor recent researchers (e.g. Matyot 2005;Gerlach and Matyot 2006;Lawrence and Henwood 2009) have examined the male genitalia of this insular taxon. Our study revealed that it could easily be distinguished from both Temnora peckoveri and T. fumosa based on the harpe shape and aedeagus structure. These features are widely used to delineate species-level taxa within the genus Temnora (e.g. Kitching 2020c). However, we hesitate to establish a new species-level taxon in the absence of available molecular data, and prefer to consider it as an insular subspecies of Temnora fumosa for now. Future DNAbased studies are urgently needed to estimate the phylogenetic distinctiveness and biogeographic affinities of this subspecies from the Inner Seychelles.
It was shown that the butterfly fauna of the Inner Seychelles shares a closer affinity to continental Africa than to Madagascar and Comoros (Lawrence 2014). The hawk moth fauna of these islands also reflects this biogeographic pattern, with four endemic taxa: Nephele leighi Joicey & Talbot, 1921, Cephonodes tamsi Griveaud, 1960, Macroglossum alluaudi De Joannis, 1893, and Temnora fumosa seychellensis ssp. nov. (Matyot 2005;Gerlach and Matyot 2006;Lawrence 2015; this study). The first species appears to have become extinct around the 1970s (Gerlach 2012), while the others are highly threatened by anthropogenic activities such as habitat loss and using of pesticides, and need special conservation efforts (Gerlach and Matyot 2006;this study). The Temnora fumosa -T. peckoveri species complex appears to be an exciting model of lepidopteran insular radiation through the Western Indian Ocean islands that must be a focus of future phylogenetic, biogeographic, and taxonomic research. Most Seychelles specimens of Agrius convolvuli were collected during the north-west monsoon (November to February) that may indicate its migrant origin on the archipelago (Matyot 2005). However, records from Praslin in July 2014 (Bippus 2016) and August 2016 (this study) do not align with this hypothesis. Our observation of adults feeding from Dracaena reflexa var. angustifolia inflorescences on Mahé seems to be useful for pollination ecology because Agrius convolvuli may serve as a pollinator of this tree, which is native to the Malagasy Subregion (Buerki et al. 2009). Several features of Dracaenas such as nocturnal flowering, strong fragrance during the late evening, and copious production of nectar on the inflorescence may be linked to pollination by animals having a nocturnal activity (Bos 1998). It was assumed that certain but unidentified hawk moth species are likely to serve as pollinators of Dracaena in Africa (Bos 1984(Bos , 1998. Conversely, Agrius convolvuli shares a long tongue and it may function as a nectar thief for plants with shorter flower tubes (Alexandersson and Johnson 2002). To the best of our knowledge, here we present the first evidence that the widespread Agrius convolvuli may be associated with Dracaenas as nectar sources.