Afrosyrphus schmuttereri, Mengual & Ssymank & Skevington & Reemer & Ståhls, 2020

Mengual, Ximo, Ssymank, Axel, Skevington, Jeffrey H., Reemer, Menno & Ståhls, Gunilla, 2020, The genus Afrosyrphus Curran (Diptera, Syrphidae), with a description of a new species, European Journal of Taxonomy 635, pp. 1-17 : 5-12

Afrosyrphus schmuttereri sp. nov.

urn:lsid:zoobank.org:act:974F2588-579F-44AA-940C-F2FB9390B195

Figs 1–2 , 3B, 3D , 4 B–C, 5B, 5F–H, 6

Afrosyrphus varipes – Schmutterer 1972a: 447; 1972b: 279; 1974:44. — Láska et al. 2000: 79.

Differential diagnosis

This species can be distinguished from A. varipes as stated in the identification key. Overall a more robust species with slightly broader abdomen, darker pilosity in calypter, scutum and abdominal segments, and male frontal triangle with black pruinosity along eye margin that looks entirely shiny ( Fig. 3 B–C). Male genitalia as in Fig. 5 F–H. Females are also darker than in A. varipes . In females, tergite 2 has a posterior dark fascia (tergite 2 entirely orange in A. varipes ; Fig. 4 A–B), the femora are darker than the tibiae (femora only slightly darker than tibiae in A. varipes ) and the face is dark in background colour (orange in A. varipes ). Both sexes have similar hind legs. The hind first tarsomere (= metabasitarsomere) appears orange and shining, as it has no long, black pile ( Fig. 5B ).

Etymology

This new species is named after its first collector, Prof. Heinrich Schmutterer, in his honour, for his dedicated work on entomology in Kenya. This species epithet is to be treated as a noun in the genitive case.

Material examined

Holotype

KENYA • ♂; Nairobi Province, Nairobi City, Chimoro ; 01°16.502′ S, 36°48.452′ E; 1686 m a.s.l. [approx. altitude]; 3 Oct. 1970; H. Schmutterer leg.; specimen identifier: ZFMK-DIP-00067253 ; ZFMK.

Paratypes

KENYA • 1 ♀; same collection data as for holotype; specimen identifier: ZFMK-DIP-00067254 ; ZFMK • 1 ♂; Taita-Taveta Co., Taita Hills, Mwatate area ; 3.48444° S, 38.33251° E; 1011 m a.s.l.; 24 Aug.– 7 Sep. 2011; R. Copeland leg.; Malaise trap below Bura Bluff, riverine forest; specimen identifier: ICIPE 9542 ; ICIPE • 3 ♂♂; Taita Taveta Co., Taita Hills, trail to Iyale ; 3.40094° S, 38.33206° E; 1867 m a.s.l.; 27 Jan. 2017; A. Ssymank leg.; ASPC • 2 ♂♂; same collection data as for preceding; G. Ståhls leg.; specimen identifiers: https://id.luomus.fi/GJ.1956, https://id.luomus.fi/GJ.1957; GenBank: MN662559 , MN662545 ; MZH • 6 ♂♂; same collection data as for preceding; 28 Jan. 2017; X. Mengual leg.; specimen identifiers: ZFMK-DIP-00019820 , 00019826 , 00019828 to 00019829 , 00019831 , 00015961 ; ZFMK • 2 ♂♂; same collection data as for preceding; specimen identifers: ZFMK-DIP-19822 to 19823 ; NMK • 5 ♂♂; same collection data as for preceding; M. Reemer leg.; NBC • 1 ♂; same collection data as for preceding; NMK • 11 ♂♂; same collection data as for preceding; J.H. Skevington leg.; specimen identifiers: CNC657049 to 657051 , CNC653515 to 653522 ; CNC • 2 ♂♂; same collection data as for preceding; specimen identifiers: CNC653523 to 653524 ; NHK • 1 ♂; same collection data as for preceding; specimen identifier: CNC653525 ; USNM • 3 ♂♂; same collection data as for preceding; 1 Feb. 2017; X. Mengual leg.; specimen identifiers: ZFMK-DIP-00019825 , 00019827 , 00015960 ; ZFMK • 1 ♂; same collection data as for preceding; specimen identifier: ZFMK-DIP-00015967 ; alternative specimen identifier: CNC1565136 ; GenBank: MN662563 ; ZFMK • 1 ♀; Eastern Province, Njuki-ini Forest , near forest station; 0.51660° S, 37.41843° E; 1455 m a.s.l.; 14–28 Aug. 2007; R. Copeland leg.; Malaise trap, inside indigenous forest; specimen identifier: USNM ENT 01518184 ; USNM .

UGANDA • 1 ♀; Western Region , Ankole District; 30 Dec. 1975; M. Paulus leg.; specimen identifier: CNC DIPTERA 102961 ; GenBank: MN662536 ; CNC • 6 ♂♂; Western Region, Kabale District, Bwindi Impenetrable National Park, Ruhija Section ; 1.06114° S, 29.77811° E; 2314 m a.s.l.; 14 Dec. 2018; M. Reemer leg.; NBC • 1 ♂; same collection data as for preceding; CNC • 1 ♂; same collection data as for preceding; MZH • 1 ♂; same collection data as for preceding; RMCA • 1 ♂; same collection data as for preceding; specimen identifier: ZFMK-DIP-00061259 ; GenBank: MN662534 ; ZFMK .

Description

Male

HEAD ( Figs 3D , 4C ). Face with distinct, low facial tubercle and with 3–4 grooves, black medially and yellow laterally, yellow pilose with seldom black pile on dorsal half and a shiny, bare median vitta, with dense pale pruinosity covering yellow lateral areas; gena yellow, with a small black macula at eye margin, yellow pilose with pale pruinosity dorsally; lunule black, with violet iridescence; frons black, with long black pile, shiny medially, with black pruinosity along eye margin (following pale pruinosity of face) and dorsally at eye angle; vertical triangle black, black pruinose, black pilose; antennal base inflated, protruded; antennal pits clearly separated; antenna elongated, black pilose, scape partly brown, pedicel and postpedicel black; postpedicel longer than scape and pedicel together; arista black, bare; eye almost bare, with a few scattered pile; occiput pale pruinose.

THORAX ( Fig.4 B–C).Scutum black, densely pale pruinose, with long yellow and brown pile;postpronotum paler, bare, densely pale pruinose; postalar callus yellow; scutellum yellow, pale pruinose, mostly dark pilose with some pale pile on anterior and posterior margins, subscutellar fringe with long, yellow pile. Pleuron black except katatergum yellow, densely pale pruinose, yellow pilose; metaepisternum bare; metasternum bare; postmetacoxal bridge incomplete; calypter yellow, mostly yellow pilose, ventral calypter with brown fringe and fine erect pile on posterior part of dorsal surface; plumule long, pale; halter pedicel and capitulum yellow; posterior spiracular fringes yellow.

WING. Hyaline, stigma yellow except dark brown basally; membrane bare basally, cells c, br and bm entirely bare, apical cells microtrichose but bare very basally; alula microtrichose.

LEGS. Coxae and trochanters black, mostly yellow pilose; fore and mid femur yellow at base very narrowly and on apical half, darker basally; fore femur with long pile posteriorly, black apically and yellow basally; mid femur similar, but also with long pile anteriorly; fore and mid tibia yellow, yellow pilose; fore and mid tarsomeres yellow; hind coxa and hind trochanter with tuft of black pile medially; hind femur and hind tibia brown; hind femur with dense dorsal and ventral fringes of long pile, yellow on basal half and black on apical half; hind tibia with dense dorsal and ventral fringes of long black pile; hind tarsomeres pale.

ABDOMEN ( Fig. 4 B–C). Unmargined, narrowly oval, long pilose. Tergite 1 yellow, densely pale pruinose, yellow pilose; tergite 2 yellow on basal half and posterior margin, black on posterior half, with posterior margin yellow, pale pilose anteriorly and laterally, dark pilose medially on posterior half, densely pale pruinose; tergite 3 yellow on basal half, black on posterior half and on lateral margins, yellow pilose laterally and dark pilose medially, with some pale pile on anterior margin, densely pale pruinose, with two fasciate areas on posterior half less pruinose; tergite 4 black with a yellow fascia on posterior margin, with two medial yellow maculae on anterior half, yellow pilose laterally and dark pilose medially, densely pale pruinose, with two fasciate areas on posterior half less pruinose, smaller than on tergite 3; tergite 5 black, pruinose, black pilose. Sternite 1 yellow, with long yellow pile; sternites 2 and 3 yellow anteriorly and black posteriorly, with long yellow and black pile; sternite 4 black, long black pilose.

MALE GENITALIA. As in Fig. 5 F–H.

Female

Similar to male except normal sexual dimorphism and as specified in diagnosis.

Variation

Based on studied material, colouration of pile on scutum and scutellum may vary slightly in amount of dark pile, ranging from little to many.

Length (N=4): body 12.7 mm (12.5–12.8 mm); wing 10.9 mm (10.8–11.0 mm).

Genetics

A total of five specimens was successfully sequenced; three 5′-COI sequences with a length of 658 bp (https://id.luomus.fi/GJ.1957,Genbank: MN662545 ;https://id.luomus.fi/GJ.1956,Genbank: MN662559 ; ZFMK-DIP-00061259; Genbank: MN662534 ), one 627 bp long (ZFMK-DIP-00015967, Genbank: MN662563 ) and one sequence that was 307 bp long (CNC DIPTERA 102961, Genbank: MN662536 ). The obtained DNA barcodes have an uncorrected pairwise distance of 0.08–1.52% among the specimens of this new species and differ by 5.54–6.54% from the two COI sequences obtained for A. varipes .

Biology

Schmutterer used larvae of Afrosyrphus to study their biological response as predators of common aphid species in East Africa ( Schmutterer 1972b) or as prey for East African ants ( Schmutterer 1972a). Schmutterer (1974) reared larvae of Afrosyrphus feeding on several hosts on six species of plants belonging to five different families from Kenya (preys and host plants are summarized in Table 1 ). He wrote that larvae of Afrosyrphus “of older stages of development stand out in comparison to those of many other aphidophagous Syrphidae of East Africa by their relatively broad, strongly flattened body. The greenish yellow of the last larval stage turns brownish 2–3 days before pupation. The drop-shaped, brown pupa has at its rear end a relatively long extension formed from a pair of stigmatic tubes.” Schmutterer (1974) also stated that “in laboratory experiments, mature larvae ready to pupate are quiescent under certain conditions and can survive several weeks without damage”. He noted that at constant temperature, low humidity causes the quiescence, and guessed that Afrosyrphus spans longer periods of drought as a quiescent larva under field conditions. This could be the reason why adults almost disappear in the highlands of Kenya during dry seasons (Schmutterer 1974).

Ssymank (2012) collected four adult specimens of A. varipes between 10:00 and 12:00 at full sun on a hilltop with a single flowering tree, Phyllanthus discoideus (Baill.) Müll.Arg. (Euphorbiaceae) . However, specimens of the new species from Taita Hills were collected between 10:00 and 11:00, hovering high between large trees in the shade. These specimens were all males and clearly using the opening between the trees on the slope as a landmark while waiting for females to appear. This landmark mating strategy is common in syrphids and similar to hilltopping, but the flies may use any type of landmark from a trail to a forest opening, rocks or a particular tree ( Skevington 2008). The trees in the shade were close to the forest margin of a primary lower montane cloud forest ( Fig. 1A ), in a small valley invaded by the South American invasive angel’s trumpet of the family Solanaceae , Brugmansia suaveolens (Humb. & Bonpl. ex Willd.) Bercht. & J.Presl. Schmutterer (1974) reported larvae of Afrosyrphus feeding on the aphid Myzus persicae (Sulzer, 1776) from the closely related invasive Solanum seaforthianum Andrews ; thus, B. suaveolens might be the host plant of the aphids for the Afrosyrphus larvae in the Taita Hills area.

Regarding the specimens collected from Bwindi Impenetrable National Park ( Uganda), they were collected between 10:00 and 11:00, hovering in a sunspot in dense, moist forest over the top of a small tree approximately 3 m high, at heights of between 3 and 6 m ( Fig. 1B ). Once the area fell into shade, no more specimens could be found.

The type locality is in Nairobi City, probably the urban park and Nairobi riverside in or near Chiromo. According to the host plants in Table 1 reported by Schmutterer (1974), the vegetation and habitat is ruderal, with tall herb vegetation on deep soils probably adjacent to the Nairobi River. The larvae obviously use different aphid species on a variety of plant families, including aphids living on up to 4 m tall herbs like the spinach rhubarb ( Rumex abyssinicus Jacq. ) and the invasive Brazilian nightshade ( Solanum seaforthianum ). Some humidity may play an important role in supporting good aphid populations and the larval development of Afrosyrphus . We assume, based on our own records, that the primary habitat is forest margins or canopy gaps in lower montane cloud forest, where tall lush herb vegetation naturally grows, and that the type locality represents the secondary habitat type of the species.

Distribution

Species known from Uganda and Kenya ( Fig. 2 ).

Remarks

The material collected and reared by Schmutterer (1972a, 1972b, 1974) was originally identified as Afrosyrphus varipes , but our study of this material revealed that it belongs to A. schmuttereri sp. nov. The puparium description by Láska et al. (2000) was based on material reared by Schmutterer (1974); thus, Láska et al. (2000) described the puparium of A. schmuttereri sp. nov. Moreover, Láska et al. (2000) stated that the immature stages the authors used to describe the puparium of Afrosyrphus were collected on 30 Oct. 1970 by Prof. Schmutterer from colonies of the aphid Brachycaudus aegyptiacus (Hall, 1926) in Nairobi. After study of all the published works by Schmutterer (1972a, 1972b, 1974), we think that Láska et al. (2000) were referring to the material from Chiromo (Nairobi) collected on 3 Oct. 1970, as no other immature specimens were collected in October 1970 in Nairobi on B. aegyptiacus . Reared adults from those immatures collected on 3 Oct. 1970 belong to the type series of A. schmuttereri sp. nov., i.e., the holotype male (ZFMK-DIP-00067253) and a paratype female (ZFMK-DIP-00067254).

Figures

Fig. 1. Localities where Afrosyrphus schmuttereri sp. nov. was collected. A. Sampling point in the trail to Iyale (Taita Hills, Kenya). B. Sampling point in the Ruhija Section of the Bwindi Impenetrable National Park (Uganda). Red circle indicates exactly where the flower flies were hovering.

Fig. 2. Known distribution of Afrosyrphus varipes Curran, 1927 (red triangles) and Afrosyrphus schmuttereri sp. nov. (black circles).

Fig. 3. A. Afrosyrphus varipes Curran, 1927, ♂ (ZFMK-DIP-00015968), dorsal view. B. Afrosyrphus schmuttereri sp. nov., paratype, ♂ (ZFMK-DIP-00019829), dorsal view. C. Afrosyrphus varipes, ♂ (ZFMK-DIP-00015968), lateral view. D. Afrosyrphus schmuttereri sp. nov., paratype, ♂ (ZFMK- DIP-00019829), lateral view. Scale bars: 1 mm.

Fig. 4. A. Afrosyrphus varipes Curran, 1927, ♀ (CNC DIPTERA 102962), dorsal view. B. Afrosyrphus schmuttereri sp. nov., paratype, ♀ (CNC DIPTERA 102961), dorsal view. C. Afrosyrphus schmuttereri sp. nov., paratype, ♂ (ZFMK-DIP-00019829), dorsal view of head. D. Afrosyrphus varipes, ♂ (USNM ENT 00114576), frontal view of head. Arrows on C and D indicate the frontal triangle. Scale bars: 1 mm.

Fig. 5. A. Afrosyrphus varipes Curran, 1927, ♀ (ZFMK-DIP-00015969), hind leg. Arrow indicates the long black pile on the hind first tarsomere (= metabasitarsomere). B. Afrosyrphus schmuttereri sp. nov., paratype, ♂ (ZFMK-DIP-00019829), hind leg. C–E. Afrosyrphus varipes, ♂ (ZFMK-DIP-00015968), genitalia. C. Epandrium and surstyli, lateral view. D. Hypandrium, postgonites and aedeagus, lateral view. E. Epandrium, cerci and surstyli, dorsal view. F–H. Afrosyrphus schmuttereri sp. nov., paratype, ♂ (ZFMK-DIP-00019829), genitalia. F. Epandrium and surstyli, lateral view. G. Hypandrium, postgonites and aedeagus, lateral view. H. Epandrium, cerci and surstyli, dorsal view. Scale bars: A–B = 1 mm; C–H = 0.25 mm.

Tables

Table 1. Reported prey, host plants and localities for Afrosyrphus schmuttereri sp. nov. in Kenya (adapted from Schmutterer 1974). Hemipteran names follow Favret (2019) and plant names follow The Plant List (2013).

Prey (Aphidoidea)	Host plant	Locality and dates
Brachycaudus aegyptiacus (Hall, 1926)	Rumex abyssinicus Jacq. (Polygonaceae)	Nairobi Co., Chiromo: 11 Sep. 1970, 3 Oct. 1970, 16 Nov. 1970
Brevicoryne brassicae (Linnaeus, 1758)	Brassica oleracea L. ( Brassicaceae )	Taita-Taveta Co., Taita Hills: 16 Nov. 1970; Nairobi Co., Chiromo: 5 Sep. 1970
Uroleucon compositae (Theobald, 1915)	Baccharoides lasiopus (O.Hoffm.) H.Rob. (Asteraceae)	Kiambu Co., Upper Kiambu: 30 Jan. 1970; Nairobi Co., Chiromo: 14 Jul. 1970, 28 Aug. 1970, 3 Oct. 1970, 22 Oct. 1970, 14 Dec. 1970, 22 Jan. 1971
Hyperomyzus lactucae (Linnaeus, 1758)	Sonchus oleraceus (L.) L. ( Asteraceae )	Nairobi Co., Chiromo: 24 Oct. 1970
Macrosiphum rosae (Linnaeus, 1758)	Rosa sp. ( Rosaceae )	Nairobi Co., Convent Drive: 7 Oct. 1970, 3 Nov. 1970
Myzus persicae (Sulzer, 1776)	Solanum seaforthianum Andrews (Solanaceae)	Nairobi Co., Chiromo: 18 Jan. 1971