Female, Kenya, NMK. Holotype locality: Yatta. Holotype labels: KENYA, Yatta, 1°13'49.59"S 37°27'28.41"E, 1184m, coll. ICIPE. Voucher code: CNC507547.

3 females (CNC507548, CNC507549, CNC507553), 3 males (CNC50750, CNC50751, CNC50752); same locality of holotype. Paratypes deposited in the CNC, ICIPE and NMK.

There are 10 DNA barcodes in BOLD from Madagascar, Saudi Arabia, South Africa and Yemen (Fig. 4) whose sequences match those of the Yemen holotype and paratypes and thus we consider them all as conspecific. However we only include in the type series those specimens from Kenya that we were able to examine.

Metasoma with T3 dark brown to black centrally, yellow laterally; hind legs mostly yellow, except for metacoxa (mostly black, with small yellow spot on apical 0.1), brown spots on apical 0.1 of metafemur (dorsally), apical 0.1 of metatibia dark brown, and metatarsus entirely dark brown; tegula and humeral complex yellow; fore wing with most veins brown. Besides coloration, C. icipe has scuto-scutellar sulcus with eight carinae; T1 almost parallel-sided, very slightly widening towards posterior margin; T2 relatively small, quadrate and not covering the entire surface of the tergum, and T3 1.3x as long as T2 length. The above combination of characters is sufficient to separate the species from all other described species of Afrotropical Cotesia, but see the Detailed diagnosis section below for one-to-one comparisons of C. icipe versus every other species. Beyond morphological characters, from a molecular perspective there is also sufficient information to recognize the new species. Eight out of the 12 previously described Afrotropical species of Cotesia have DNA barcodes available in BOLD (Fig. 5), and they are all clearly different from C. icipe.

Female (Fig. 1). Metasoma brown dorsally, except for T3 (which is centrally brown, laterally yellow); most of laterotergites and sternites yellow, hypopygium brown; F2 length 1.78–2.00 × F14 length; metafemur length 3.60–3.80 × metafemur width; metatibia inner spur length 1.17 × metatibia outer spur length; metatibia inner spur length 0.52 × first segment of metatarsus length; T1 entirely sculptured with coarse punctures and a polished knob centrally on posterior margin; T1 very slightly widening towards posterior margin (width at posterior margin 1.1–1.2 × its width at anterior margin); T1 length centrally 1.5–1.7 × its width at posterior margin; T2 entirely sculptured, with coarse punctures along all margins and longitudinal striation centrally; T2 more or less rectangular, width at posterior margin 2.0 × its length centrally; T3 smooth, with rows of setae that are more dense on posterior half of tergite; T3 length centrally 1.3 × T2 length centrally; ovipositor sheaths length 0.16–0.19 × metatibia length. Body measurements (all in mm). Body length: 2.20–2.50; fore wing length: 2.20–2.50; ovipositor sheaths: 0.12–0.15; metafemur length 0.65; metafemur width: 0.17–0.18; metatibia length: 0.76–0.80; metatibia inner spur: 0.21; metatibia outer spur: 0.18; first segment of metatarsus: 0.40. T1 length centrally: 0.35–0.37; T1 width at anterior margin: 0.19; T1 maximum width: 0.25; T1 width at posterior margin: 0.22–0.24; T2 width at posterior margin: 0.32; T2 length centrally: 0.16; T3 length centrally: 0.21; length of F1: 0.17–0.19; length of F2: 0.16–0.18; length of F3: 0.16–0.17; length of F14: 0.09; length of F 15: 0.08; length of F16: 0.10.

Figure 1. 

Cotesia icipe, female holotype. A Habitus lateral B Wings C Hind leg, hypopygium and ovipositor D Head frontal E Head and mesosoma dorsal F Propodeum and metasoma dorsal.

Male (Fig. 2). As female but with darker metasoma dorsally, sometimes with T3 entirely dark brown to black.

Figure 2. 

Cotesia icipe, male paratype. A Habitus lateral B Head and mesosoma dorsal C Head frontal D Wings E Propodeum and metasoma dorsal.

Based on 4,000+ parasitism cases observed under laboratory condition at icipe in Kenya, C. icipe is a solitary larval endoparasitoid of Spodoptera littoralis (Boisduval, 1833) and Spodoptera exigua (Hübner, 1808) (Lepidoptera, Noctuidae). It was successfully reported to attack those two noctuid species tested on amaranth. However, it failed to parasitize three Crambidae species tested on the same host plant: Spoladea recurvalis (Fabricius, 1775), Udea ferrugalis (Hübner, 1796) and Herpetogramma bipunctalis (Fabricius, 1794). Further studies of host range are warranted to explore the full potential of the new species in the biological control of key pests in small scale farming conditions in Africa. The female prefers ovipositing on second instar host larvae. The development time from egg to adult is two weeks and ovipositing females fed with honey can live more than two weeks at 25°C (our unpublished data).

Afrotropical: Kenya, Madagascar, Saudi Arabia, South Africa, Yemen (Fig. 3).

Figure 3. 

Known distribution of Cotesia icipe in the Afrotropical region. Blue dots show distribution based on specimens of the type series (Kenya), red dots show distribution based on specimens with DNA barcodes matching those of the Kenya series.

Currently (as of September 2017) there are in BOLD 19 available sequences from five Afrotropical countries: Kenya (9 sequences), Madagascar (1), Saudi Arabia (3), South Africa (1) and Yemen (5). Although we could not examine the specimens from Saudi Arabia or South Africa, their sequences are identical to the rest, and thus we consider them all to represent the species Cotesia icipe. They belong to BIN BOLD:ABZ7318; however, that BIN is likely to contain more than one species, as the sequences currently assigned to it are grouped in different clusters (Fig. 4). The Afrotropical sequences are in a single cluster, separated by more than 1% different base pairs from the other sequences in that BIN (from Australia, French Polynesia and Pakistan, all in separate clusters). Solving the species limits for this BIN is beyond the scope of this paper, but for the time being we consider that only the Afrotropical sequences represent Cotesia icipe.

Figure 4. 

Neighbor-joining tree (K2P) of all specimens in the Barcoding of Life Data System (BOLD) currently associated with BIN BOLD:ABZ7318 (for explanation on the BIN concept see Methods of this paper). The cluster highlighted in Yellow in the tree shows the specimens considered in the present paper as Cotesia icipe.

Figure 5. 

Neighbor-joining tree (K2P) of Afrotropical species of Cotesia in the Barcoding of Life Data System (BOLD) with over 500 base pairs; data accessed on September 2017. Specimens named as “Cotesia jft52” in BOLD actually belong to the species Cotesia icipe (cluster highlighted in Yellow), and specimens named as “Cotesia jft68” in BOLD actually belong to the species Cotesia chrysippi (Viereck, 1911).

We dedicate this species to the “International Centre of Insect Physiology and Ecology (icipe)” for its long-term promotion of Integrated Pest Management and for building the capacity of thousands of African young scientists over the years in insect sciences.

Additionally, and to facilitate future work on the group, we detail below how each of the other 12 species of Cotesia previously described from the Afrotropics individually differ from C. icipe.

Cotesia bignellii (Marshall, 1885) has metasoma (entirely) and hind legs (mostly) dark brown, very different from the body color of C. icipe as detailed above. C. bignellii also parasitizes a different family of Lepidoptera hosts (Nymphalidae) and it is mostly distributed in Europe (Yu et al. 2016).

Cotesia chrysippi (Viereck, 1911) parasitizes a different family of Lepidoptera hosts (Nymphalidae) (Yu et al. 2016) and it has a very different color, with a reddish-brown metasoma dorsally, dark brown tegula and humeral complex and fore wing with most veins white.

Cotesia decaryi (Granger, 1949) is only known from Madagascar and probably represents a local endemic from that country. It parasitizes a different family of Lepidoptera hosts (Lasiocampidae) (Yu et al. 2016). It has metacoxa mostly smooth (rugose-punctate in C. icipe), T1 clearly widens towards posterior margin, T2 covers most of the tergum dorsally, and T3 is about the same length than T2 (T3 1.3 × as long as T2 length in C. icipe).

Cotesia flagellator (Wilkinson, 1930) is only known from Uganda (Yu et al. 2016); it has scuto-scutellar sulcus with 4–5 (very rarely 6) major carinae (C. icipe has 8–9, rarely 7 major carinae); metacoxa mostly smooth, with only indefinite coarse punctures anterodorsally (metacoxa mostly with shallow punctures in C. icipe); T2 2.2 × as long as wide at posterior margin (2.0 × in C. icipe); T3 1.5 × as long as T2 length (1.3 × in C. icipe).

Three related species, Cotesia flavipes Cameron 1891, Cotesia sesamiae (Cameron, 1906) and Cotesia typhae Fernández-Triana, 2017, have all been recently revised in Kaiser et al. (2017), including extensive illustrations. They are all part of the flavipes complex and can be distinguished by relatively short antennae (much shorter than body length, usually not surpassing the length of head and mesosoma; whereas the antenna of C. icipe is comparatively much longer, about as long as body), body relatively depressed, and metasoma extensively to slightly pale in coloration (yellow, orange or light brown) but clearly much lighter in color than C. icipe. Beyond the substantial morphological differences these three species parasitize different host species within the families Crambidae and Noctuidae (Yu et al. 2016, Kaiser et al. 2017).

Cotesia pistrinariae (Wilkinson, 1929) has a strongly narrowed T1 centrally, which is unique among all known species of Cotesia; extensive illustrations of pistrinariae can be found in Gupta et al. (2016). It also parasitizes a different family of Lepidoptera hosts (Pieridae) (Yu et al. 2016).

Cotesia vestalis (Haliday, 1834) has T1 clearly widening towards posterior margin and T2 covering most of the tergum dorsally, both tergites are also much more coarsely sculptured than in C. icipe; the coxae (especially pro- and mesocoxae) are also darker colored as compared to icipe. There are many host records attributed to this species (Yu et al. 2016), some of them dubious; they include mostly Erebidae, Nymphalidae and Plutellidae, with a couple of Noctuidae species different from those parasitized by C. icipe.

Cotesia vanessae (Reinhard, 1880) is mostly a Palearctic species, recently found to have spread into the Nearctic (Hervet et al. 2014), and only marginally distributed in Africa (Yu et al. 2016). It has tegula and humeral complex dark brown to black, metasoma entirely black dorsally, and legs mostly dark brown. Numerous host records, some of them certainly inaccurate, are attributed to this species (Yu et al. 2016).

Of all described Afrotropical species Cotesia ruficrus (Haliday, 1834) looks most similar to C. icipe from a morphological perspective; however, it has T1 clearly wider at posterior margin as compared to anterior margin (almost the same width in C. icipe); T2 covers most of the tergum surface; and vein R1 in fore wing is comparatively much shorter, about the same length of pterostigma, and with the distance between end of vein R1 and the end of vein 3RSb being more than 0.4 × the length of vein R1 (in C. icipe the vein R1 in fore wing is comparatively much longer, clearly longer than pterostigma length, and with the distance between end of vein R1 and the end of vein 3RSb being less than 0.2 × the length of vein R1); also, the overall coloration is lighter and more reddish than in C. icipe. Furthermore, from a biological point of view, C. ruficrus is a gregarious parasitoid while C. icipe is a solitary parasitoid. Numerous host records, some of them certainly inaccurate, are attributed to C. ruficrus (Yu et al. 2016).

Cotesia rugosa (Szépligeti, 1914) presents the most difficult case to assess, as it is only known from the male holotype, collected in 1912 at an altitude of 2,000 m, on the western side and near of Mount Kenya (Szépligeti 1914, Papp 2008). C. icipe has been collected not too far from that locality, at close to 1,200 m. However, and according to the original description, C. rugosa has different colored legs, including many red areas (legs mostly yellow in C. icipe, with a few areas brown); tegula reddish-brown (yellow in C. icipe); T2 as long as T3 (0.7–0.8 × in C. icipe); T1 is described as ‘almost transversal’ (Szépligeti 1914: 184) which, within the context of the Microgastrinae species described in that paper, seems to indicate that T1 is strongly widened towards posterior margin, i.e., T1 width at posterior margin is about as long as T1 length medially (whereas T1 is 1.5 × as long as wide at posterior margin in C. icipe).