3. Results
3.1. Molecular Results
Our molecular analysis verified the monophyly of
Ruschiola and of all ten species described here (bootstrap values of 87–100%) (
Figure 2). Mean intraspecific sequence divergence was 0.0–1.1%, and mean interspecific divergence among
Ruschiola species was 2.6–10.2% (
Table 2). Sequence divergence between
Ruschiola and the Lasiopterini outgroups used here averaged at 10.4%.
Ruschiola attenuata from
Mesembryanthemum splendens was retrieved as sister to all other species included here that develop in Ruschioideae host plants, paralleling the sister position of Mesembryanthemoideae relative to the Ruschioideae within Aizoaceae [
5,
27].
Ruschiola attenuata is also the only species that is relatively easily to distinguish from other
Ruschiola species based on adult morphology. The high degree of morphological uniformity among other
Ruschiola species makes it difficult to distinguish between them without genetic data and detailed information on host–plant associations, which may be indicative of recent diversification.
3.2. Ruschiola Dorchin, New Genus
Type species: Ruschiola succulenta Dorchin and van Munster
Diagnosis:
Ruschiola is a striking, morphologically uniform genus of medium to large-sized lasiopterines. The adult body is densely covered by black and white scales, whereby abdominal tergites are almost completely black, with only a thin transverse line of white scales along the posterior margin (
Figure 3A). This contrasts with the typical color pattern of most lasiopterine genera from Chenopodiaceae (e.g.,
Baldratia Kieffer,
Stefaniola Kieffer,
Careopalpis Marikovskij), in which scales on the abdominal tergites form two or three black triangles on a white background (or occasionally vice versa). The number of antennal flagellomeres is irregular within a species, as is also usual for
Lasioptera Meigen,
Baldratia and
Stefaniola, and contrary to the invariable number of 10 flagellomeres in
Careopalpis and
Suaediola Dorchin. Palpi are one or two segmented and their shape may vary considerably within the same species and individual (e.g.,
Figure 4B). Vein R
4+5 of the wing is notably longer than in most other lasiopterine genera, joining C at about three quarters of the wing length rather than around its mid-length (
Figure 3C). The ovipositor is much shorter than that of
Lasioptera and
Ozirhincus Rondani, but longer than that of most lasiopterine genera from Chenopodiaceae. It is very uniform within the genus, with a well-developed, heavily sclerotized lateral plate that does not form a clear aculeus posteriorly, contrary to the distinct, ventrally curved aculeus in
Baldratia and
Careopalpis, straight aculeus in
Stefaniella Kieffer, or dorsally curved aculeus in
Stefaniola,
Izeniola Fedotova and
Suaediola. Pupae have well-developed antennal horns but no facial horns, and larvae have a bidentate sternal spatula, conspicuous and long shafted in some species to vestigial and barely visible in others.
The genus currently includes the ten species described here, but many more are likely to be found as the full diversity of Aizoaceae host plants in South Africa and Namibia is yet to be explored. All known Ruschiola species develop in conspicuous leaf galls or in leaf tissues without visible external deformation. Many plants that host Ruschiola species are also inhabited by Asphondylia Loew species, which gall buds or flowers rather than leaves, and will be dealt with elsewhere. The evolutionary relationships between Ruschiola and other genera in the Lasiopterini are unclear at present and warrant further study.
Adult. Head (
Figure 3B): Eye facets round; gap between eyes on vertex 0–2 facets wide. Antenna: scape cylindrical, pedicel globose, both densely covered by long, dark scales; flagellomeres 10–18, barrel shaped to nearly quadrate (
Figure 3B), 1–2 times as long as wide, apical flagellomere either shorter or longer than preceding flagellomeres, rounded or tapered apically, often consisting of two merged flagellomeres; each flagellomere with two whorls of appressed circumfilla with 1–2 longitudinal connections and two more-or-less ordered whorls of strong setae; setae of distal whorl strongly curved at base, stronger, longer and originating from larger sockets than setae of proximal whorl; flagellomeres evenly setulose elsewhere. Frontoclypeal membrane with many long hair-like setae and scales. Palpi 1–2 segmented, shape may vary within species and individual. Labella diminutive to well developed.
Thorax: Wing (
Figure 3C) densely covered by delicate setulae, posterior margin fringed by long, delicate hair-like setae; C broken beyond junction with R
4+5; R
4+5 reaching C at about three quarters of wing length; C and R
4+5 thick, densely covered by black scales to meeting point; M present as fold; CuA
1 and CuA
2 form a fork. Legs: Tarsal claws toothed on all legs, tooth curved close to base; empodia as long as or much longer than bend in claws; pulvilli about half as long as claws.
Female abdomen (
Figure 3D): Densely covered by scales; tergites mostly black, except for thin stripe of white scales along posterior margin. Tergites 1–7 rectangular, with anterior pair of sensory setae, posterior row of strong setae, and evenly distributed scales; tergite 8 with considerably reduced pigmentation or not differentiated from surrounding membrane, without vestiture other than anterior pair of sensory setae. Sternites 2–6 rectangular, without anterior sensory setae, with few setae forming posterior row along pigmented section and several setae medially; sternite 7 same but setose throughout; sternite 8 with small patch of pigmented area or undifferentiated from surrounding membrane. Ovipositor (
Figure 4E): Segment 8 with large lateral group of straight to slightly curved setae on prominent sockets. Segment 9 with pigmented rod-like sclerite along segment. Cercal segment in straight angle relative to segment 9, with ventral field of setulae, strongly sclerotized lateral plate harboring dozens of curved setae on prominent sockets to mid-length, group of shorter setae extending ventrally to unpigmented area, and eight to ten conspicuously long, curl-like setae on distal half, followed by field of shorter, upright acicular setae extending to apical lamella; apical lamella short-cylindrical to rectangular, barely longer than lateral plate, setose and setulose.
Male abdomen (
Figure 3E): Tergites 1–7 rectangular, vestiture as in female; pigmented part of tergite 8 greatly reduced or tergite completely undifferentiated from surrounding tissue. Sternites 2–7 as in female, pigmented area of sternite 8 considerably smaller than preceding; all sternites nearly evenly setose, denser setation on posterior ones.
Terminalia (
Figure 5A): Gonocoxite widest at mid-length; mediobasal lobe wide, robust, almost same width throughout length, with several short lobes apically, densely setose. Gonostylus widest at proximal third, with wide or medium-sized apical tooth; evenly or partially setulose, grooved elsewhere. Hypoproct rounded, truncated, or with shallow depression apically; shape varies within same species, setulose. Cerci separated almost to base, setose and setulose.
Larva (third instar): Light yellow to bright orange. Integument covered by verrucae. Spatula bidentate, conspicuous, with well-developed shaft in some species (e.g.,
Figure 5C) to vestigial and barely visible in others. Sternal papillae usually asetose; four lateral papillae, asetose or two of which with very short setae, pleural papillae with distinct setae; three terminal papillae on each side, with long setae (
Figure 5D).
Pupa: Light to dark orange. Antennal bases well developed into tapered horns, parallel or splayed; no facial horns or papillae; short cephalic setae on elevated bases; prothoracic spiracle short and wide, with trachea forming loop inside spiracle (
Figure 3F). Basal part of facial area on each side with conspicuous lobe extending laterally. Dorsum of abdominal segments with wide transverse fields of tapered spicules across mid-section (
Figure 3G).
Etymology: The genus name is feminine, combining
Ruschia Schwantes, a plant genus of 213 leaf succulent, perennial, shrubby species [
1], which hosts the greatest diversity of gall midge species among the Aizoaceae, with the diminutive suffix ‘ola’.
3.3. Ruschiola succulenta Dorchin and van Munster, New Species
Host plants: Ruschia caroli (L. Bolus) Schwantes, R. pungens (A. Berger) H. Jacobsen, Lampranthus haworthii (Donn ex Haw.) N.E.Br.
Gall and biology: This species develops in swollen, succulent leaf galls, usually 2–6 cm long and 1–1.5 cm wide (
Figure 6A–D). The galls may be green but are usually reddish, occasionally with longitudinal cracks on most of the leaf area. Each gall may contain 20–30 larvae in vaguely defined, tunnel-like chambers along the longitudinal axis of the leaf, the walls of which are drier than the surrounding succulent tissues encompassing the rigid middle part of the gall. Galls on
Lampranthus haworthii are often smaller and less conspicuous than those on
Ruschia caroli and
R. pungens, and the larval chambers in them are embedded in rigid, black tissue (probably fungal mycelia). The galls are heavily parasitized by several parasitoid Hymenoptera, including polyembryonic Platygastridae. The species is very common, and its galls can be found in large numbers at some sites, especially on
R. caroli. Adults emerged mainly in spring (August–September), but galls containing mature larvae and pupae were also found in April, suggesting that the species completes at least two generations a year during the fall and winter months. Full-sized galls were also observed on
R. caroli in summer (January), but they contained only first-instar larvae. This suggests that the larvae that hatch from eggs in spring (September–October) spend several months in the plant tissues before the galls become apparent and take several additional months to mature and pupate. The galls on all three host plants yielded a second, much smaller
Lasioptera-like species, whose smaller and more delicate larvae and pupae were found alongside the robust larvae and pupae of
R. succulenta. This second lasiopterine appears to be an inquiline and will be treated in a future publication, together with congeners we reared from several other succulent Aizoaceae.
Adult description: Head, thorax and lateral parts of abdomen white; legs black; wing surface covered by dark hair-like setae, with thick black setae on C up to meeting point with R4+5. Abdominal tergites almost entirely black, except for thin transverse line of white scales along posterior margin. Abdominal pleura white, each with small black spot.
Head (
Figure 3B): Gap between eyes on vertex one to two facets wide. Antennal flagellomeres 11–15 in female (
n = 30), 10–12 in male (
n = 16), number often differs between antennae of same individual; cylindrical to barrel shaped, progressively shorter; two adjacent flagellomeres often fused; apical flagellomere slightly pointed or evenly rounded apically. Palpus two segmented; segment 1 globose or slightly longer than wide, setulose and bearing several long setae and scales; segment 2 usually subtending and partially fused with segment 1 (
Figure 4A), cylindrical, slightly tapered, setulose; occasionally vestigial or considerably longer than segment 1 (
Figure 4B).
Thorax: Wing as in generic diagnosis; length 1.78–2.80 mm in female (
n = 40), 1.37–2.36 mm in male (
n = 17). Legs densely covered by black scales; claws evenly curved, with strongly curved tooth; empodia considerably longer than bend in claws (
Figure 4C,D); pulvilli reaching about mid-length of claws (
Figure 4D).
Female abdomen (
Figure 3D): Tergites 1–7 with anterior pair of minute sensory setae and posterior row of long setae; tergite 8 hardly differentiated from surrounding membrane, with small, irregular patch of pigmented area, or completely unpigmented, pair of sensory setae anterior to pigmented area the only vestiture (
Figure 4E). Sternites without proximal sensory setae; sternites 2–6 with unpigmented patch medially, group of long setae medially and posterior row of long setae; sternite 7 evenly pigmented, with long setae on distal two thirds; sternite 8 completely undifferentiated from surrounding membrane. Ovipositor (
Figure 4E): Segment 9 with pigmented patches proximally and strongly pigmented rod-like sclerite along segment. Cercal segment with heavily sclerotized lateral plate, slightly tapered apically but not differentiated into clear aculeus; lateral plate bearing about 30 long, curved setae up to mid-length, with additional group of 10–20, shorter setae extending ventrally to unpigmented area, and eight to ten conspicuously long, thick, erect, curl-like setae on distal half, followed by group of shorter, upright acicular setae to tip of lateral plate, extending ventrally to apical lamella; area of lateral plate ventral to curl-like setae bare, sheathing almost half height of apical lamella before abrupt attenuation toward tip. Apical lamella rectangular, barely longer than lateral plate, strongly setose and setulose along distal half. Base of cercal segment with group of strong setae proximal to setulose hypoproct, and densely setulose ventral area extending to tip of apical lamella.
Male abdomen (
Figure 3E): Tergites 1–7 as in female; tergite 8 much smaller, without posterior row of setae. Sternites 2–7 as in female, pigmented area of sternite 8 smaller than preceding.
Terminalia (
Figure 5A): Gonocoxite widest at mid-length, with numerous strong setae more or less evenly distributed; mediobasal lobe much shorter than aedeagus, almost same width throughout length or slightly narrows to apex in dorsal view, apex rugose, with multiple short setae on bulging bumps. Gonostylus widest at proximal third, setulose on proximal half and furrowed beyond both dorsally and ventrally, with wide apical tooth and numerous long, evenly distributed setae. Aedeagus wide, truncated apically in dorsal view, triangular and pointed anteriorly in lateral view. Hypoproct entire, truncated, or with very shallow apical depression, two setae apically and setulose throughout. Cerci robust, strongly setose and setulose.
Larva (third instar): Antennae about twice as long as wide. Posterolateral apodemes at least twice as long as head capsule (
Figure 5B). Spatula (
Figure 5C) well developed, with short, apically rounded teeth separated by round notch; long, narrow shaft, widens posteriorly. On each side of spatula asetose sternal papilla, four lateral papillae, two of which with minute setae, and one asetose ventral papilla; pleural and dorsal papillae with long setae. Terminal abdominal segment (
Figure 5D) on each side with three papillae bearing long setae; anus ventral.
Pupa (
Figure 7A). Antennal horns straight, parallel along medial margins.
Distribution: Common in the winter rainfall areas of the Western Cape, mainly on R. caroli; collected in Worcester, Eilandia near Robertson, and the Vrolijkheid Nature Reserve.
Etymology: The species epithet is a feminine adjective, referring to the typical succulent, sausage-like galls induced by this species.
Type material: HOLOTYPE: ♀, South Africa, Western Cape, Karoo Desert National Botanical Garden, Worcester (33°36′33″ S, 19°27′01″ E), 20.ix.17, N. Dorchin, S. van Munster and C. Klak, ex leaf gall on Ruschia caroli. On permanent microscope slide in Euparal. Deposited in SAMC. PARATYPES: 6♀, 2♂, same data as holotype (1♀ ZFMK); 5♀, 4♂, Karoo Desert National Botanical Garden, Worcester, 25.viii.17, N. Dorchin, S. van Munster and C. Klak, ex Ruschia caroli (1♀ EMEUC); 2♀, 3♂, Karoo Desert National Botanical Garden, Worcester, 20.ix.17, N. Dorchin and S. van Munster, ex Lampranthus haworthii; 5♀, 1♂, Eilandia, Robertson, 15 km W, Rt60 (33°46′15″ S, 19°44′53″ E), 20.ix.17, N. Dorchin and S. van Munster, ex Ruschia pungens; 5♀, 4♂, Eilandia, Robertson, 15 km W, Rt60, 4.ix.18, N. Dorchin and S. van Munster, ex Ruschia caroli; 5♀, 4♂, Eilandia, Robertson, 15 km W, Rt60, 6.ix.2018, N. Dorchin and S. van Munster, ex Ruschia pungens; 1♀, Karoo Desert National Botanical Garden, Worcester, 27.iv.19, N. Dorchin, S. van Munster and C. Klak, ex Ruschia caroli; 2♀, 2♂, Karoo Desert National Botanical Garden, Worcester, 14.viii.19, N. Dorchin and S. van Munster, ex Ruschia caroli; 4♀, 2♂, Karoo Desert National Botanical Garden, Worcester, 14.viii.19, N. Dorchin and S. van Munster, ex Lampranthus haworthii; 1♀, Vrolijkheid Nature Reserve (33°55′04″ S, 19°52′39″ E), 15.viii.19, N. Dorchin, S. van Munster and C. Klak, ex Ruschia caroli.
Other material examined: 1♂, same data as holotype; 2♀, 1♂, 3 exuviae, Karoo Desert National Botanical Garden, Worcester, 25.viii.17, N. Dorchin, S. van Munster and C. Klak, ex Ruschia caroli; 4♀, 3♂, 4 exuviae, Eilandia, Robertson, 15 km W, Rt60, 20.ix.17, N. Dorchin and S. van Munster, ex Ruschia pungens; 2 larvae, 5 exuviae, Eilandia, Robertson, 15 km W, Rt60, 4.ix.18, N. Dorchin and S. van Munster, ex Ruschia caroli; 8 larvae, 2 exuviae, Eilandia, Robertson, 15 km W, Rt60, 6.ix.18, N. Dorchin and S. van Munster, ex Ruschia pungens; 4 larvae, Karoo Desert National Botanical Garden, Worcester, 27.iv.19, N. Dorchin, S. van Munster and C. Klak, ex Ruschia caroli; 2♀, 1 exuviae, Karoo Desert National Botanical Garden, Worcester, 14.viii.19, N. Dorchin and S. van Munster, ex Ruschia caroli.
3.4. Ruschiola attenuata Dorchin and van Munster, New Species
Characters similar to R. succulenta, except for the following:
Hostplant:Mesembryanthemum splendens L.
Gall and biology: This species induces common inflated, succulent leaf galls, typically up to 2 cm long and 0.5 cm wide (
Figure 6E,F). The gall usually occupies the entire leaf, is green, yellowish or reddish, and contains 1–3 chambers located centrally along the longitudinal leaf axis. The walls of the chambers are drier than the surrounding leaf tissue and the gall is firm to the touch. Galls are common throughout the distribution of the host plant and adult gall midges were reared from January to September, suggesting that the species completes multiple generations a year.
Adult:
Head: Antennal flagellomeres 15–18 in female (
n = 23), 13–16 in male (
n = 8), quadrate, about as long as wide, except for slightly longer flagellomeres 1 and 2 (
Figure 8A). Palpus two segmented; segment 1 globular, segment 2 as long as or about twice as long as segment 1, when longer usually tapered apically (
Figure 8B).
Thorax: Wing length: 1.46–2.44 mm in female (
n = 36), 1.74–2.47 mm in male (
n = 15). Empodia as long as or slightly longer than bend in claws (
Figure 8C).
Female abdomen: Tergite 8 with small patch of pigmented area on each side, with anterior sensory seta and sometimes 2–3 small posterior setae. Ovipositor (
Figure 8E): Segment 9 with rectangular patch of pigmented area at mid-length. Heavily sclerotized area of lateral plate ventral to curl-like setae thin, sheathing at most quarter height of apical lamella.
Male abdomen: Mediobasal lobe of gonocoxite slightly shorter than aedeagus, with shorter dorsal bulge over longer, rugose apical section (
Figure 8D).
Larva: Not studied.
Pupa (
Figure 7B and
Figure 9A): Antennal horns straight, separated by triangular gap, each split apically into longer lateral tip and shorter median tip. Face with two tiny pits in mid posterior area.
Distribution: Common wherever the host plant was found, outside or along the edge of winter rainfall areas of the Western Cape. Collected from Worcester, Laingsburg, Van Wyksdorp, and Oudtshoorn.
Etymology: The species epithet is the Latin feminine adjective term for plain, shortened or refined, with reference to the thinner and less robust lateral plate of the ovipositor compared to the ovipositor of other known Ruschiola species.
Type material: HOLOTYPE: ♀, South Africa, Western Cape, Van Wyksdorp (Watermill Farm) (33°43′50″ S, 21°28′39″ E), 26.iv.19, N. Dorchin, S. van Munster and C. Klak, ex leaf gall on Mesembryanthemum splendens. On permanent microscope slide in Euparal. Deposited in SAMC. PARATYPES: 5♀, 1♂, same data as holotype; 6♀, 1♂, Karoo Desert National Botanical Garden, Worcester, 14.viii.19, N. Dorchin, S. van Munster and C. Klak (1♀ EMEUC); 7♀, 7♂, Laingsburg, 34 km SE, R323 (33°22′52.38″ S, 21°0′41.11″ E), 5.ix.18, J. F. Colville and A. Melin (1♀, 1♂, ZFMK).
Other material examined: 4♀, same data as holotype; 1♂, Karoo Desert National Botanical Garden, Worcester (33°36′33″ S, 19°27′01″ E), 14.viii.19, N. Dorchin, S. van Munster and C. Klak; 2♀, 1♂, Oudtshoorn, 27 km S, N12 (33°46′29″ S, 22°20′35″ E), 12.x.18, S. van Munster; 9♀, 4♂, Laingsburg, 34 km SE, R323 (33°22′52.38″ S, 21°0′41.11″ E), 5.ix.18, J. F. Colville and A. Melin.
Comments: This is the only Ruschiola species that can be readily distinguished from the otherwise rather uniform species in the genus based on its adult morphology. Its flagellomeres are more numerous and significantly shorter than those of the other species described here, the empodia are about as long as the bend in the claws rather than much longer, as in other species, and the ovipositor has a thinner lateral plate and less robust apical lamella. The pupa also stands out among all other species for having apically divided antennal horns, whereas those of all other species are undivided.
3.5. Ruschiola cedarbergensis Dorchin and van Munster, New Species
Characters similar to R. succulenta, except for the following:
Host plants:Ruschia cymosa L.Bolus, R. schollii (Salm-Dyck) Schwantes, R. cf. caroli, R. cf. cedarbergensis.
Gall and biology: This species induces conspicuous but uncommon sausage-like leaf galls on
R. cymosa,
R. cf.
caroli and
R. cf.
cedarbergensis (
Figure 10A,B,D), whereas on the low, crawling
R. schollii, it develops in reddish sections of otherwise undeformed leaves (
Figure 10C). The conspicuous galls are usually 5–7 cm long and at least 1 cm wide, often with longitudinal cracks, and may occupy the entire leaf (the common case) or only parts of it. They are firm to the touch and contain many larvae that develop in vaguely defined larval chambers embedded in rigid tissues. Galls were collected in August and September only; it is therefore unknown if this species has more than one generation per year.
Adult:
Head: Antennal flagellomeres 12–14 in female (
n = 24), 11–12 in male (
n = 10); occasionally two or more flagellomeres fused to form continuous units. Palpus often appears composed of one large, globular segment, but usually with vestigial second segment “riding” on or branching from it (
Figure 11A).
Thorax: Wing length: 1.99–2.67 mm in female (n = 27), 1.99–2.63 mm in male (n = 16).
Female abdomen: Tergite 8 with small, elongate patch of pigmented area and anterior sensory seta outside of pigmented area.
Male abdomen: Gonostylus (
Figure 8C) widest at base, with clear constriction around mid-length, distal margin almost straight rather than arched, setulose along basal and most of distal sections, furrowed elsewhere.
Larva (third instar): Antennae about twice as long as wide. Spatula (
Figure 11B) only slightly longer than wide, shallow teeth rounded apically, short and wide shaft extending into two lobes posteriorly. Lateral papillae asetose. One larva found with long-shafted spatula similar to that of
R. succulenta; more sampling is needed in order to clarify if the short-shafted larvae represent early third instars with spatula that is not yet fully developed.
Pupa (
Figure 7C and
Figure 9B): Antennal horns separated by triangular gap (median edges not parallel).
Distribution: Uncommon on several Ruschia species restricted to the Cedarberg region. Recorded from Heuningvlei, Bushmans Kloof Wilderness Reserve, and Travellers Rest (Wolfdrif) near the town of Clanwilliam.
Etymology: The species epithet is feminine, combining the name Cedarberg with the Latin adjectival suffix “ensis”, which means “from the Cedarberg”, as it was only reared from several host plants in that particular region.
Type material: HOLOTYPE: ♂, South Africa, Western Cape, Bushmans Kloof Wilderness Reserve (32°06′22″ S, 19°06′42″ E), 8.viii.19, N. Dorchin and S. van Munster, ex leaf gall on Ruschia cymosa. On permanent microscope slide in Euparal. Deposited in SAMC. PARATYPES: 3♀, same data as holotype; 1♀, 1♂, Bushmans Kloof Wilderness Reserve, 14.ix.17, N. Dorchin and S. van Munster, ex. Ruschia cf. caroli; 3♀, 3♂, Travelers Rest (Wolfdrif), Cedarberg (32°01′47″ S 19°03′19″ E), 11.ix.18, N. Dorchin and S. van Munster, ex. Ruschia cymosa; 3♀, 3♂, Bushmans Kloof Wilderness Reserve, 12.ix.18, N. Dorchin and S. van Munster, ex Ruschia cf. cedarbergensis; 1♀, 1♂, Bushmans Kloof Wilderness Reserve, 12.ix.18, N. Dorchin and S. van Munster, ex. Ruschia cymosa; 5♀, Heuningvlei Nature Reserve (32°09′59″ S, 19°01′46″ E), 13.ix.18, N. Dorchin and S. van Munster, ex Ruschia schollii; 7♀, 3♂, Bushmans Kloof Wilderness Reserve, 8.viii.19, N. Dorchin and S. van Munster, ex Ruschia cf. caroli; 3♀, 1♂, Bushmans Kloof Wilderness Reserve, 8.viii.19, N. Dorchin and S. van Munster, ex Ruschia cymosa; 4♀, 4♂, Travelers Rest (Wolfdrif), Cedarberg, 8.viii.19, N. Dorchin and S. van Munster, ex Ruschia cf. caroli.
Other material examined: 1 exuviae, same data as holotype; 2 exuviae, Travelers Rest (Wolfdrif), Cedarberg, 11.ix.18, N. Dorchin and S. van Munster, ex. Ruschia cymosa; 6 larvae, Bushmans Kloof Wilderness Reserve, 12.ix.18, N. Dorchin and S. van Munster, ex Ruschia cf. cedarbergensis; 3 larvae, 3 exuviae, Bushmans Kloof Wilderness Reserve, 12.ix.18, N. Dorchin and S. van Munster, ex. Ruschia cymosa; 5 exuviae, Bushmans Kloof Wilderness Reserve, 8.viii.19, N. Dorchin and S. van Munster, ex Ruschia cf. caroli; 4 exuviae, Travelers Rest (Wolfdrif), Cedarberg, 8.viii.19, N. Dorchin and S. van Munster, ex Ruschia cf. caroli.
Comments: The large, succulent leaf galls of this species on most of its host plants are very similar to those caused by
R. succulenta and the two species appear to be closely related based on molecular data (
Figure 2). Nevertheless, slight diagnostic morphological differences do exist between them, including the shorter and more robust palpus in
R. cedarbergensis, the typical shape of the gonostylus (
Figure 11C), the much shorter and wider larval spatula and the more widely separated pupal antennal horns (parallel in
R. succulenta). It is noteworthy that
R. cedarbergensis causes large, conspicuous galls on three of its host plants, whereas on
Ruschia schollii, no obvious galls develop, and the presence of the gall midge in the plant is evident only because of pupal skins that remain stuck in reddish sections of the otherwise undeformed leaves (
Figure 10C).
3.6. Ruschiola namaqua Dorchin and van Munster, New Species
Characters similar to R. succulenta, except for the following:
Host plants:Ruschia viridifolia L.Bolus, and R. goodiae L.Bolus.
Gall and biology: This species develops in smooth, succulent, reddish leaf galls that usually occupy most of the leaf area (
Figure 10E,F). The galls are 3–4 cm long and 1.0–1.5 cm wide, each containing numerous larval chambers, and can be locally very common. They were sampled at several sites in late July to mid-August, at which time they contained second and third instar larvae, pupae, and empty pupal skins. It is currently unknown if this species has more than one generation a year.
Adult:
Head: Antennal flagellomeres 12–13 in female (
n = 39), 10–12 in male (
n = 35). Palpus usually one segmented, either globular or with tapered extension, sometimes with basal bulge, occasionally two segmented, with tapered second segment much longer than first (
Figure 12A).
Thorax: Wing length: 1.70–2.39 mm in female (n = 39), 1.51–2.20 mm in male (n = 36).
Male abdomen: Gonostylus evenly setulose along ventral part.
Larva (third instar): Spatula (
Figure 12C): Vestigial, irregularly pigmented, about as long as wide, without clear teeth or shaft, somewhat more sclerotized anteriorly. Sternal papillae setose, lateral papillae asetose. Pigmented area of spatula sometimes encroaching lateral papillae area.
Distribution: Galls are common on at least two Ruschia species in Namaqualand. Collected from Kamieskroon, Grootvlei Pass and Namaqua National Park (Skilpad Rest Camp).
Etymology: This species is named after the Namaqualand region, to which it is apparently restricted. The name is a feminine noun in apposition.
Type material: HOLOTYPE: ♀, South Africa, Northern Cape, Namaqua National Park (Skilpad Camp), (30°09′58″ S, 17°46′09″ E), 26.vii.19, N. Dorchin, S. van Munster and C. Klak, ex leaf gall on Ruschia goodiae. On permanent microscope slide in Euparal, deposited in SAMC. PARATYPES: 9♀, 9♂, same data as holotype. 1♀, 1♂, Kamieskroon (30°12′00″ S, 17°56′06″ E), 9.viii.17, N. Dorchin, S. van Munster and C. Klak, ex Ruschia viridifolia; 10♀, 10♂, Grootvlei Pass, eastern base (30°12′53″ S, 17°46′07″ E), 10.viii.17, N. Dorchin, S. van Munster and C. Klak ex Ruschia goodiae; 12♀, 18♂, Kamieskroon, 26.vii.19, N. Dorchin and S. van Munster, ex Ruschia viridifolia (1♀, 1♂ ZMFK, 1♀, 1♂ EMEUC).
Other material examined: 1♀, 2 exuviae, Kamieskroon, 9.viii.2017, N. Dorchin, S. van Munster, C. Klak ex Ruschia viridifolia; 4♀, 2♂, 2 exuviae, Grootvlei Pass, eastern base, 10.viii.2017, N. Dorchin, S. van Munster and C. Klak ex Ruschia goodiae; 1♀, Grootvlei Pass, 10.viii.2017, N. Dorchin, S. van Munster and C. Klak, ex Ruschia viridifolia; 1♀, 2 exuviae, Kamieskroon, 26.vii.2019, N. Dorchin and S. van Munster, ex Ruschia viridifolia; three larvae, two exuviae, same data as holotype.
Comments: The adults and pupae of this species are virtually indistinguishable from those of R. succulenta, whereas the larvae have a greatly reduced spatula relative to the well-developed spatula of R. succulenta and setose rather than asetose sternal papillae. The galls are smaller, less rigid and without longitudinal cracks, which are typical of R. succulenta, R. cedarbergensis and other (undescribed) species from other host plants in Namaqualand.
3.7. Ruschiola bubonis Dorchin and van Munster, New Species
Characters similar to R. succulenta, except for the following:
Host plant:Jordaaniella spongiosa (L.Bolus) H.E.K. Hartmann.
Gall and biology: This species develops without obvious gall formation in the massive, fleshy leaves of the host plant, and was discovered in the field only due to the empty pupal skins stuck in the leaves (
Figure 13A,B). Therefore, plant material was collected haphazardly in an attempt to rear the gall midges, a method that proved successful. Several individuals develop in the same leaf, and the species probably has more than one generation per year, at least during winter, as adults were reared in mid-July and mid-August.
Adult:
Head: Antennal flagellomeres 12–14 in female (
n = 10), 11–13 in male (
n = 5). Palpus morphology variable; occasionally one segmented but usually two segmented, with second segment either shorter or longer than first segment, with long scales (
Figure 14A).
Thorax: Wing length: 1.24–2.51 mm in female (n = 14), 2.00–2.42 mm in male (n = 6).
Female abdomen: Tergite 8 with small patch of pigmented area or completely undifferentiated from surrounding membrane.
Male abdomen: Pigmented area of tergite 8 narrow, band-like or much shorter than preceding.
Terminalia (
Figure 14B): Aedeagus narrow, parallel sided and apically truncated in dorsal view. Hypoproct entire.
Larva (third instar) (
Figure 14C): Posterolateral apodemes about as long as head capsule. Spatula virtually absent, evident only as small and vaguely defined pigmented area. On each side asetose sternal papilla and four asetose lateral papillae, one of which set closer to median line of body, the other three grouped together. Pleural, dorsal and terminal papillae with short setae.
Pupa (
Figure 7E and
Figure 9D): Antennal horns slightly ventrally arched, widely separated at base, abruptly splayed along median margins from mid-length to tapered apex.
Distribution: Locally common on its host plant in the Namaqua National Park (coastal section), the only site where the plant was sampled.
Etymology: The epithet
bubonis is the feminine genitive form of
bubo—the Latin term for owl—with reference to the splayed antennal horns of the pupa, giving it the appearance of a horned owl (
Figure 7E).
Type material: HOLOTYPE: ♂, South Africa, Northern Cape, Namaqua National Park (coastal section), (30°24′40″ S, 17°24′59″ E), 28.viii.18, N. Dorchin, S. van Munster and C. Klak, ex Jordaaniella spongiosa. On permanent microscope slide in Euparal. Deposited in SAMC. PARATYPES: 4♀, 2♂, same data as holotype; 10♀, 3♂, Namaqua National Park (coastal section), 25.vii.19, N. Dorchin, S. van Munster and C. Klak.
Other material examined: 1 larva, 3 exuviae, same data as holotype.
Comments: This species stands out among congeners with known pupae for the splayed, owl-like antennal horns of its pupa compared to the triangular or parallel-sided antennal horns of other species. Females cannot be distinguished from those of other species, with the exception of R. attenuata, but males have a consistently entire hypoproct, whereas the shape of the hypoproct in other species varies. The single available larva lacks a distinct spatula, and its pleural, dorsal and terminal papillae bear much shorter setae than those of other species.
3.8. Ruschiola quagga Dorchin and van Munster, New Species
Characters similar to R. succulenta, except for the following:
Host plant:Ruschia holensis L. Bolus.
Gall and biology: This species develops in inflated leaf galls, 2–3 cm long and about 1 cm wide, green to reddish (
Figure 13C). Each gall contains a few larvae. In young galls containing second instar larvae, the larvae are found in vaguely differentiated chambers embedded in the spongy leaf tissue. Third instar larvae and pupae are found in more defined chambers with drier walls compared to the juicy surrounding tissues. The galls are heavily parasitized by polyembryonic hymenopteran parasitoids. Galls were collected only once, in late August, at which time they contained either second or third instar larvae and pupae. It is unknown if the species has more than one generation per year.
Adult:
Head: Antennal flagellomeres 13 in female (
n = 3), unknown in male (no males with complete antennae). Palpus one segmented, 1.3–5.5 times as long as wide, usually tapered (
Figure 14D); when short, tear shaped and based on small palpiger; shape may differ between palpi of same individual.
Thorax: Wing length: 2.2–2.33 mm in female (n = 8), 1.81–1.97 mm in male (n = 3).
Male abdomen: Hypoproct truncated apically.
Larva (third instar): Antennae about 1.5 times as long as wide. Posterolateral apodemes about as long as head capsule. Spatula with shallow depression between short and blunt teeth, long and narrow shaft (
Figure 13E). Sternal and lateral papillae asetose, barely visible. Pleural, dorsal and terminal papillae with minute setae.
Pupa (
Figure 9E): As described under
R. succulenta.
Distribution: Found only once in the Knersvlakte (Quaggaskop Farm).
Etymology: This species is named after the extinct South African Plains Zebra—Quagga. It was collected only at Quaggaskop Farm in the Knersvlakte. The name is a feminine noun in apposition.
Type material: HOLOTYPE: ♀, South Africa, Western Cape, Quaggaskop Farm, Knersvlakte Nature Reserve (31°24′59″ S, 18°35′43″ E), 26.viii.18, N. Dorchin, S. van Munster and C. Klak, ex leaf gall on Ruschia holensis. On permanent microscope slide in Euparal. Deposited in SAMC. PARATYPES: 7♀, 3♂, 2 larvae, 2 exuviae, same data as holotype.
3.9. Ruschiola timida Dorchin and van Munster, New Species
Characters similar to R. succulenta, except for the following:
Host plant:Scopelogena bruynsii Klak.
Gall and biology: This species is rare, or at least very difficult to find. It develops without causing any obvious deformation in the leaves of its host plant and was reared only by collecting plant material haphazardly after finding a small number of empty pupal skins stuck in leaves (
Figure 13D). On one occasion, a slightly inflated leaf was found, but all adults that we reared emerged from leaves with no external signs of infestation. Adults were reared only from one site, although we sampled the host plant at other sites within the same area, where the plant is rather common. In 2017 and 2018, plants were collected and adults emerged from them in mid-September; in 2019 plants were sampled in early August, but no adults emerged. Additional sampling of the host plant is needed at different times of the year to confirm if the species has only one generation in early spring.
Adult:
Head: Antennal flagellomeres 13–14 in female (
n = 9), 10–12 in male (
n = 3); apical flagellomere often “budding” from penultimate flagellomere or two apical flagellomeres fused (
Figure 14F). Palpus usually one segmented, tapered, about twice as long as wide, or two segmented, with second segment much smaller than first (
Figure 14G).
Thorax: Wing length: 1.95–2.42 mm in female (n = 9), 1.68–1.93 mm in male (n = 4).
Male abdomen: Hypoproct truncated or with deep notch (
Figure 14H).
Larva: Unknown.
Pupa: Unknown.
Distribution: This species was found on only a few occasions in the Cedarberg (Travellers Rest).
Etymology: The species name is a feminine adjective derived from the Latin term for timid, referring to the lack of external signs of its presence in the leaves of the host plant and the difficulty of finding and rearing it.
Type material: HOLOTYPE: ♀, South Africa, Western Cape, Travellers Rest, Clanwiliam (32°05′03″ S, 19°05′24″ E), 13.ix.18, N. Dorchin and S. van Munster, ex leaf of Scopelogena bruynsii. On permanent microscope slide in Euparal. Deposited in SAMC. PARATYPES: 6♀, 4♂ same data as holotype. 2♀ Travellers Rest, Clanwilliam, 15.ix.17, N. Dorchin and S. van Munster.
3.10. Ruschiola furtiva Dorchin and van Munster, New Species
Characters similar to R. succulenta, except for the following:
Host plant:Ruschia dichroa (Rolfe) L. Bolus.
Gall and biology: This species develops in inconspicuous leaf galls, the only external deformation of the leaf being a slight change of color from green to red. The presence of the gall midges in the leaves was recognized only by the empty pupal skins that were found stuck in slightly discolored leaves. Although the same site was visited twice in subsequent years, and host plant material was collected, gall midges were reared only once, in mid-September; no other information is currently available on the life history of this species.
Adult: Head: Antennal flagellomeres 12–13 in female (n = 4), 11–12 in male (n = 4). Palpus one segmented, 2–4 times as long as wide, tapered apically.
Thorax: Wing length: 2.13–2.36 mm in female (n = 5), 1.83–1.93 mm in male (n = 4).
Female abdomen: Tergite 8 undifferentiated from surrounding tissue.
Male abdomen: Gonostylus completely setulose dorsally and ventrally. Hypoproct truncated.
Larva: Unknown.
Pupa: Similar to that of R. succulenta, based on pupal exuviae.
Distribution: This species was found only once in Bushmans Kloof Wilderness Reserve in the Cedarberg region, to which it is probably endemic, similar to its host plant [
40].
Etymology: The species epithet is a feminine Latin adjective for secret or hidden, referring to the lack of external signs of its presence in the leaves of its host plant.
Type material: HOLOTYPE: ♀, South Africa, Western Cape, Bushmans Kloof Wilderness Reserve (32°06′22″ S, 19°06′42″ E), 14.ix.17, N. Dorchin and S. van Munster, ex leaf gall on Ruschia dichroa. On permanent microscope slide in Euparal. Deposited in SAMC. PARATYPES: 4♀, 4♂, same data as holotype.
Other material examined: 8 exuviae, same data as holotype.
3.11. Ruschiola leipoldtiae Dorchin and van Munster, New Species
Characters similar to R. succulenta, except for the following:
Host plant:Leipoldtia laxa L. Bolus and L. schultzei (Schltr. and Diels) Friedrich.
Gall and biology: This species induces common leaf galls on its host plants, which occupy either the entire leaf or only part of it (
Figure 15A–D). The galls are pinkish-red, rigid, and contain multiple larval chambers (10–20 on
L. schultzei, fewer on
L. laxa) embedded in a mass of tough tissue in the center of the fleshy leaf. Galls were found and midges were reared in late July and early August. No additional information is available on the life history of this species; however, in December no galls were found on
L. laxa at the same site from which they were collected in August of the previous year; hence, the species appears to be inactive during the summer.
Adult:
Head: Antennal flagellomeres 11–13 in female (
n = 26), 11–12 in male (
n = 10). Palpus one or two segmented (
Figure 16A,B), number sometimes varies in same individual; when one segmented, segment ovoid, 1.5–2.0 times as long as wide; when two segmented, segment 2 subequal to or longer than segment 1 and appears to “ride” on it (
Figure 16B). Labella prominent and elongated, 1.5 times as long as wide (
Figure 16A).
Thorax: Wing length: 1.93–2.32 mm in female (n = 44), 1.60–2.18 mm in male (n = 38).
Male abdomen: Gonostylus widest at proximal third, distal margin almost straight rather than arched (
Figure 16D). Hypoproct truncated or with shallow notch.
Larva (third instar): Posterolateral apodeme about as long as head capsule. Spatula well developed, long shafted (
Figure 16C). On each side of spatula asetose sternal papilla and 4 asetose lateral papillae, one of which set further apart from the other three.
Pupa (
Figure 10F and
Figure 11F): Antennal horns separated by triangular gap (median edges not parallel).
Distribution: This species was found in Springbok and in the Namaqua National Park (Skilpad camp), suggesting that it has a wide distribution in Namaqualand.
Etymology: This species is named after its host plant genus Leipoldtia, which in turn is named after the renowned South African physician, poet and botanist, C. Louis Leipoldt (1880–1947). The epithet is a feminine noun in the genitive case.
Type material: HOLOTYPE: ♂, South Africa, Northern Cape, Namaqua National Park (Skilpad camp) (30°09′58″ S, 17°46′09″ E), 21.vii.19, N. Dorchin, S. van Munster and C. Klak, ex leaf gall on Leipoldtia schultzei. On permanent microscope slide in Euparal. Deposited in SAMC. PARATYPES: 12♀, 12♂, same data as holotype; 17♀, 10♂, Springbok (29°40′53″ S 17°53′03″ E), 5.viii.17, N. Dorchin, S. van Munster and C. Klak.
Other material examined: 4♀, 15♂, same data as holotype; 14♀, 7 larvae, 10 exuviae, Springbok, 5.viii.2017, N. Dorchin, S. van Munster and C. Klak.
Comments: This species stands out among its congeners for its conspicuous labella and dense cover of hair-like setae on the adult frons and male gonopods. The gonostylus is straight along its posterior margin rather than arched, as in most species. The pupa resembles that of R. cedarbergensis in having antennal horns that are not parallel along their median margins (although this character depends on the angle from which the pupae are viewed and may be distorted in slide-mounted exuviae).
3.12. Ruschiola celebrata Dorchin and van Munster, New Species
Characters similar to R. succulenta, except for the following:
Host plants:Mitrophyllum mitratum (Marloth) Schwantes, M. clivorum (N.E.Br.) Schwantes.
Gall and biology: This species was reared from inflated leaf galls that usually occupy the base of the leaf, but which occasionally occupy its entire length (
Figure 15E,F). Often only one of the two leaves on the same node is affected (
Figure 15E). The galls were locally very common on the two host plants at a particular spot, but absent from other spots at the same site. As would be expected, galls were larger on
M. mitratum (2–4 cm) than on the smaller and more delicate
M. clivorum (1–2 cm). Each gall contained 10–30 larvae, as attested by the large numbers of empty pupal skins that were stuck in them. The galls are not particularly harder than the soft, uninfested leaves, and most are green but sometimes yellowish. This species was observed and reared only once, in late July, and no additional information is available on its life history.
Adult:
Head: Antennal flagellomeres 12–15 in female (
n = 13), 11–12 in male (
n = 2). Palpus one segmented, 1.5–4 times as long as wide, fusiform with truncated apex (
Figure 16E).
Thorax: Wing length: 2.22–2.73 mm in female (n = 13), 2.13–2.44 mm in male (n = 3).
Female abdomen: Tergite 8 with small patch of heavily pigmented area.
Larva: Unknown.
Pupa (based on exuviae): Antennal horns with small subapical bulge (
Figure 16F).
Distribution: This species was found on only one occasion at the south-eastern end of the Vyftienmyl se Berg Inselberg, ca. 30 km east of Port Nolloth.
Etymology: The species epithet is a feminine Latin adjective for crowded or populous, with reference to the large number of larvae in the gall.
Type material: HOLOTYPE: ♀, South Africa, Northern Cape, Vyftienmyl se Berg Inselberg, Port Nolloth, 20 km E (29°14′41″ S, 17°06′32″ E), 22.vii.19, N. Dorchin, S. van Munster and C. Klak, ex leaf gall on Mitrophyllum clivorum. On permanent microscope slide in Euparal. Deposited in SAMC. PARATYPE: 5♀, 3♂, same data as holotype. 7♀, same data as holotype, from Mitrophyllum mitratum.
Other material examined: 4 exuviae, same data as holotype; 3 exuviae, same data as holotype, from Mitrophyllum mitratum.
Comments: The pupa of this species is unique among other known pupae in this genus for having a small but distinct bulge just below the apex of the antennal horn (compare
Figure 16F,G).