Macrotarsipodes Le Cerf, 1916

Bartsch, Daniel & Sáfián, Szabolcs, 2022, Taxonomic changes and review of the genera Tipulamima Holland, 1893 and Macrotarsipodes Le Cerf, 1916 stat. rev. (Lepidoptera: Sesiidae: Sesiinae), Zootaxa 5094 (1), pp. 103-128 : 117-119

Macrotarsipodes Le Cerf, 1916 stat. rev.

Le Cerf, 1916: 13,

type species, Macrotarsipodes tricinctus Le Cerf, 1916 , by monotypy.

Hampson 1919: 56 (synonym of Tipulamima ), Dalla Torre & Strand 1925: 6, Gaede 1929: 518 (synonym of Tipulamima ), Naumann 1971: 30, 31, Heppner & Duckworth 1981: 41 (synonym of Tipulamima ), Fletcher & Nye 1982: 95, Pühringer & Kallies 2004: 33 (synonym of Tipulamima ).

Remark. Heppner & Duckworth (1981) and Pühringer & Kallies (2004) placed Macrotarsipodes in Synanthedonini (as a synonym of Tipulamima ). Macrotarsipodes shows strong similarities with Macrotarsipus Hampson, [1893] and Lepidopoda Hampson, 1900 from Southeast Asia ( Arita & Gorbunov 1995, Kallies personal communication, unpublished, own results). In particular, the similar structures of labial palpus and antenna, the wing pattern, the general body shape, as well as the genitalia of both sexes. In a revision of Macrotarsipus Arita & Gorbunov (1995) also placed this genus in Synanthedonini , based on the presence of apical scale tuft on the antenna and the matching wing venation. The first mentioned feature is a synapomorphy of the subfamily Sesiinae , the second nearly identical in most Synanthedonini and Sesiini . Both should therefore be regarded as plesiomorphic and are thus not suitable for assignment to subordinate categories. Arita & Gorbunov (1995), however, point out that the exact systematic position of Macrotarsipus remains unclear and the genitalia structures of both sexes are completely different from all known tribes of the family namely in the male the very prominent gnathos and the unique shapes of uncus and valva including the structure of their sensory hairs as well as in the female the shapes of ostium bursae and antrum.

The current understanding of the Synanthedonini (as Aegeriini ) dates back to Naumann (1971). He lists some possible synapomorphies of the tribe, paying special attention to the structure of the sensory hairs of the valva. Later authors largely adopt this view (eg. Heppner & Duckworth 1981, Špatenka et al. 1999). We also follow Naumann’s definition and place Macrotarsipodes , Macrotarsipus and Lepidopoda in Synanthedonini due to some of the typical features of this tribe, i.e., the wing venation with short common stalks of forewing veins R4/R5 and hindwing veins M3/CuA1, and the male genitalia with bifurcate setae on valva and uncus. Further investigations, including molecular methods, are required to enable proper placement of Macrotarsipodes , Macrotarsipus and Lepidopoda .

Redescription. Small to medium sized clearwing moths with alar expanses of 17–25 mm and moderate sexual dimorphism. Head: labial palpus proximally upturned, distally straight, smoothly scaled dorsally, roughly ventrally, first palpomere short, second palpomere one and a half as long as third; proboscis well developed and certainly functional; frons smooth; antenna slightly clavate, ciliate in male and unciliate in female. Thorax: rather strong. Legs slender, smoothly scaled; tibia of fore- and midleg distally with somewhat longer, slightly tufted scales; hindleg with tibia and tarsus distinctly elongated, therefore leg up to twice as long as abdomen, tibia and terminal tarsomeres distally with some longer, slightly tufted scales, therefore appearing somewhat thickened distally. Wings: transparent areas well developed; apical area usually well developed (very small in M. pedunculata ), broadest apically; forewing venation with veins R 1 and R 2 strongly approximated but not fused, R 4 and R 5 coincided to about half way; hindwing with M 2 arising from costad portion of discal vein, M 3 and CuA 1 with short common stalk. Abdomen: slender, first two segments distinctly waisted especially in male, analtuft reduced.

Male genitalia. Bradley (1968) presented line drawings of the genitalia of both sexes. Tegumen and uncus almost completely fused to a narrow, long segment, with a broad, distally bilobed protrusion from proximal part of tegumen (gnathos?); uncus long, oval, bipartite ventro-laterally with rows of long, bifurcate, basad pointing setae. Vinculum exceptionally short, forming a narrow, traverse, sclerotized band. Valva elongate, dorsal and ventral margin somewhat concave, distally with a more or less enlarged and weak sclerotized part; inner surface without typical crista sacculi, but with longitudinal fold in proximal half; central part, distal portion of ventral margin and longitudinal fold densely covered with bristle-like, short bifurcate setae, weak sclerotized part sparsely covered with clubbed, apically angled setae. Saccus small and short. Phallus straight, slender with short, slightly extended, proximally flat or bilobed coecum penis; vesica long, distally tapering, proximally enlarged with hook-shaped tooth.

Female genitalia. Apophyses unspecialized; ostium bursae and antrum well sclerotized; ductus bursae and bursa copulatrix membranous, the latter round without signum.

Diagnosis. The genus can be defined as follows: (1) scaling of labial palpus short and ventrally roughened, without hair-like scales; (2) hindlegs smooth, about twice as long as abdomen; with first tarsomere half as long as tibia; (3) abdomen proximally instead of basally waisted, analtuft absent; (4) tegumen with large, prominent and proximally shifted, double-pointed gnathos; (5) valva distally with enlarged, weak sclerotized part; (6) juxta very short; (7) corpus bursae round and simple, without signum. Characters (3), (4) and (5) are possible synapomorphies of the genus.

Superficially, Macrotarsipodes resembles some other genera of the subfamily with very long legs, such as Teinotarsina Felder & Felder, [1874] or Podosesia Möschler, 1876 . However, based on important structures of the genitalia, with similar location of the gnathos, rather similar shape of the valva and nearly identical wing venation, it seems closely related to Macrotarsipus Hampson, [1893] from South-East Asia ( Arita & Gorbunov 1995). The latter is unique within the Sesiidae by the extraordinary long hindlegs, which have tufted scales at the four terminal tarsomeres, forming a flat paddle. Males of the two genera, Macrotarsipodes and Macrotarsipus , are characterized by the very unusual shape of the tegumen and valva; the very short, a transverse band forming juxta; the phallus, with bilobed coecum penis. Females by the well sclerotized ostium bursae and antrum.

Males of Macrotarsipodes differ considerably from those of Macrotarsipus by the broad and flat, distally bilobed gnathos (finger-shaped with roof-shaped lobe distally in Macrotarsipus ), and the absence of a crista sacculi of the valva (present in in Macrotarsipus ). Females differ by the location of ostium bursae, which is located between segments 7 and 8 in Macrotarsipodes , in the middle of segment 8 in Macrotarsipus .

Barcoding. Sequence data of Macrotarsipodes leptosceles ( Bradley, 1968) are generated by Scott Miller. Data of Macrotarsipus and two related, indeterminate species are available from BOLD. For phylogenetic analysis see text fig.2 .

Biology. Two species, M. leptosceles and tricinctus , have been recorded as agricultural pests on sweet potatoes ( Ipomoea batatas , Convolvulaceae ) and are mentioned in literature of agricultural pest control (e.g. Ames et al. 1996, Bradley 1968, Zhang 1994). Nderitu & Sila et al. (2009) highlight M. leptosceles as “one of the most destructive and important economic pest species” on sweet potatoes in Eastern Kenya. Sweet potatoes are native to Central America, but are now cultivated worldwide as an important crop in tropical and subtropical regions. The infestation by caterpillars of Macrotarsipodes is a result of secondary adaptation, and African species of Convolvulaceae would certainly be the native hosts of this species. Nevertheless, many species of Macrotarsipodes may have a high potential as pest species and there is a serious risk of introduction into regions or even continents outside of their native distribution range.

Figures

text FIG.2. Phylogenetic analysis (MrBayes using RAxML usertree) of Macrotarsipodes (based on COI barcode sequences, 10 million generations, values are posterior probabilities). Sister groups Macrotarsipus Hampson, [1893], Lepidopoda dasysceles (Bradley, 1968) and two indeterminate Synanthedonini from Cameroon and Tanzania.