A new gregarious parasitoid species, Microplitis idreesae (Hymenoptera, Braconidae, Microgastrinae) reared from Mythimna sp. (Lepidoptera, Noctuidae), with a key to the species of Microplitis in the Kingdom of Saudi Arabia Author Al-Sabi, Mohammad Nafi Solaiman https://orcid.org/0000-0003-2277-4587 College of Veterinary Medicine, P. O. Box: 400, King Faisal University, Al-Ahsa, 31982, Saudi Arabia malsabi@kfu.edu.sa Author Arias-Penna, Diana Carolina https://orcid.org/0000-0002-9601-3038 Unaffiliated, Bogota D. C., Cundinamarca, Colombia Author Idrees, Nabila Rayed Nashaat College of Veterinary Medicine, P. O. Box: 400, King Faisal University, Al-Ahsa, 31982, Saudi Arabia Author Al-Jabr, Omar A. https://orcid.org/0000-0001-9342-343X College of Veterinary Medicine, P. O. Box: 400, King Faisal University, Al-Ahsa, 31982, Saudi Arabia Author Alhudaib, Khalid A. https://orcid.org/0000-0002-3598-6506 College of Veterinary Medicine, P. O. Box: 400, King Faisal University, Al-Ahsa, 31982, Saudi Arabia Author Almaghasla, Mustafa I. https://orcid.org/0000-0002-2834-3318 College of Veterinary Medicine, P. O. Box: 400, King Faisal University, Al-Ahsa, 31982, Saudi Arabia text Journal of Hymenoptera Research 2023 2023-03-27 96 101 120 http://dx.doi.org/10.3897/jhr.96.99114 journal article http://dx.doi.org/10.3897/jhr.96.99114 1314-2607-96-101 4699FA5332C640DB94DDD6C197E50374 C7DB2F78322F5B4C80C1002ECB5EE177 Microplitis idreesae Arias-Penna & Al-Sabi sp. nov. Figs 3A-J , 4A-K Type material. Holotype . The Kingdom Of Saudi Arabia. 1 Female; the Eastern Province, Al-Ahsa Oasis, Hofuf, King Faisal University student housing; 25°20'34.1412"N , 49°36'6.2316"E ; 154m; 18.xii.2020; Nabila Idrees leg.; reared on undetermined species of Mythimna ( Lepidoptera : Noctuidae ); caterpillar collected from the wall of the housing compound at KFU; cocoons formed on 19.xii.2020; adults emerged on 27.xii.2020, 29.xii.2020, and 30.xii.2020; PW: 12-2020; (KFU-Vet). Paratypes . 5 (2 females, 3 males); same data as for holotype; (KFU-Vet). Diagnosis. T1 slightly elevated and rounded posteriorly; fore wing with quadrangular areolet and vein r straight; notauli strongly impressed anteriorly but disappearing gradually as they approach the scutoscutellar sulcus. Description. Female. Body length (head to apex of metasoma): 2.6, fore wing length: 2.45, antenna length: 3.36. Body length in females varies between 2.6 to 2.9. Colour (Fig. 3 A, B, E ). General body coloration black except for scape, pedicel, first ten proximal antennal flagellomeres, labrum, mandibles, maxillary and labial palps, and tegula dark yellow-brown. All legs dark yellow-brown except: all claws dark brown and hind coxae with basal third dark brown, second third black, and distal third yellow-brown. T1 dark brown-black, posteriorly with a dark yellow-brown area, lateral ends of T1 dark brown; T2 completely dark yellow-brown; T3 with anterior half dark yellow-brown and posterior half black; T4 and following completely black. In lateral view, T1-T2 completely dark yellow-brown; T3 with anterior half dark yellow-brown and posterior half black, T4 and following completely black. S1-S2 dark yellow-brown, S3 with anterior half dark yellow-brown and posterior half black, and hypopygium brown. Figure 3. Microplitis idressae sp. nov. female A habitus B mesosoma and T1, dorsal view C, G head C dorsolateral view G lateral view D, H mesosoma D dorsal view H lateral view E, I metasoma E dorsal view I lateral view F, L antenna F antenna L flagellomere J, K wings J fore K hind. Head (Figs 3A, C, G ). In frontal view, rounded with pubescence long and moderately dense. Proximal thirteen antennal flagellomeres longer than wide (0.18:0.06), last antennal flagellomere pointed and longer than penultimate (0.16:0.05, 0.12:0.05), all antennal flagellomeres setose, antenna longer than body (3.36, 2.6); scrobes shallow. Face rounded with dense fine punctations, interspaces wavy, and longitudinal median carina incomplete, visible only at the anterior third. Fronto-clypeal suture absent. Temple wide, punctate, and interspaces wavy. Inner eye margins diverge slightly at scrobes. POL shorter than OOL (0.10, 0.12). Malar suture present but long and moderately dense pubescence makes its observation difficult. Median area between lateral ocelli with a depression. Vertex, rounded in lateral view, narrow in dorsal view. Mesosoma (Figs 3A, B, D, H ). Mesosoma dorsoventrally convex, length: 1.4. Mesoscutum anteriorly convex and posteriorly flat with punctation distinct anteriorly, satiny posteriorly, and interspaces wavy/lacunose; medial furrow of mesoscutum incomplete, distinct only anteriorly. Notauli distinct anteriorly but disappearing gradually as they approach the scutoscutellar sulcus. Scutellum long and slender, posteriorly sloped and fused with medioposterior band of scutellum, scutellar punctation fine scattered throughout, in profile scutellum flat and on the same plane as mesoscutum, phragma of the scutellum slightly visible; medioposterior band of scutellum sculptured and overlapping slightly the medioanterior pit of metanotum; axillary trough of scutellum demilune and dorsal axillary trough of scutellum groove with complete undulate/reticulate carinae. Scutoscutellar sulcus markedly bowed with seven irregular and deep foveae, the two middle ones larger than the others, area just behind scutoscutellar sulcus smooth, shiny, and nearly at the same level as mesoscutum (flat). Anterior furrow of metanotum with setiferous lobes and not as well delineated as posterior furrow which is thick and smooth; medioanterior pit of metanotum elongated with a complete transverse carina in its third posterior, overlapping completely the medioposterior band of metanotum which is difficult to differentiate; axillary trough metanotum with few incomplete parallel carinae. Propodeum with a distinct median longitudinal carina and areolate rugose sculpturing covering its entire surface; propodeal spiracles surrounded by carina; nucha ringed by radiating carinae. In lateral view, upper pronotum with imbricate sculpture throughout, centrally with a distinct furrow of deep irregular foveae, and lower pronotum with two types of sculpture, anterior half imbricate and posterior half smooth. Propleuron finely sculptured. Metasternum convex. Mesopleuron convex, lower mesopleuron finely imbricate, centrally smooth, dorsal margin with a distinct row of foveae forming an L-shape inverted, precoxal sulcus crenulate. Epicnemial ridge truncate-pyramid shape, anteriorly convex, posteriorly truncate. Legs (Fig. 3A, B ). Ventral margin of fore telotarsus entire, with a tiny straight seta, fore telotarsus basally narrow and apically wide, and longer than the fourth tarsomere (0.14, 0.08). Hind coxa finely punctate throughout, without outer depression; inner spur of hind tibia slightly longer than outer spur (0.13, 0.12); entire surface of hind tibia with dense strong spines uniform by color and length; hind telotarsus longer than the fourth tarsomere (0.17, 0.09); hind femur length:wide (0.70:0.17), hind tibia length (0.42), hind basitarsus length (0.13). Wings (Fig. 3J, K ). Fore wing: length 2.45; stigma dark brown but paler at base; quadrangular areolet, vein r-m spectral; vein 3-SR shorter than vein r-m, both veins forming an angle at their junction; vein 2-SR curved and longer than 3-SR; vein 2-M straight and swollen; r vein straight; 1-R1 length 0.58; vein 1-M straight; vein 1-SR+M slightly curved; vein 2-SR+M spectral; vein 3CU1 tubular; vein CU1a mostly spectral but a small anterior portion absent; vein CU1b absent; vein 2-1A tubular; vein cu-a slightly curved, reaching the edge of 1-1A vein, anterior half tubular, and posterior half spectral. Hind wing (length 2.0) with vannal lobe narrow, convex, with long setae. Metasoma (Fig. 3A, E, I ). T1 virtually parallel-sided (barrel-shaped) over most of its length but narrowing over the posterior 1/3 (length 0.41; maximum width 0.2; minimum width 0.13), distally rounded, slightly elevated medially, almost nitid with scarce sculpturing laterally and scattered pubescence in the posterior third. Median area on T2 polished, truncate-trapezoidal, slightly wider than longer (length 0.16, maximum width 0.17; minimum width 0.12); lateral grooves delimiting the median area clearly defined and not reaching the posterior edge (length median area 0.17, length T2 0.2); T3 smooth, as long as T2 (0.2, 0.2). Pubescence on the hypopygium scattered. Cocoons (Fig. 4H ). Cocoons are oval with light olive drab coloration, lacking any kind of remarkable ornament, and the silk fibers looking disordered and fluffy. Cocoons are located both on the anterior part of the back and lateral sides of the alive host caterpillar. Figure 4. Microplitis idressae sp. nov. male A, G habitus A dorsal view G lateral view B mesosoma and T1, dorsal view C metasoma, dorsal view D legs E antenna F, I-K head F dorsal view I lateral view J frontal view K ventral view H cocoon. Male (Fig. 4A-K ). Similar to female except T2 with lateral areas dark yellow-brown and T3 completely dark brown. Body length varies between 2.5 to 2.8. Etymology. This species is named in honor of Nabila Rayed Nashaat Idrees who found the infested caterpillar. She is a bachelor student from the College of Veterinary Medicine at the King Faisal University, Al-Ahsa, KSA. Distribution. The Kingdom of Saudi Arabia, Eastern Province, Hofuf. Biology. Gregarious larval endoparasitoid wasp. Essentially all but one of the larvae successfully spun their cocoons (15 out of 16), out of which emerged 8 females and 7 male adults. The adults obtained from pupae incubated at room temperature (n=8) eclosed on the eighth day after pupation, whereas those incubated in the environmental chamber (n=7) took one to two days longer to emerge. It is worth mentioning that in nature, eclosion is tied to both internal physiological processes and externally received cues (e.g., evaporative cooling, heat retention by moist litter, - Janzen et al. 2003 ). This may suggest the adaptation of the wasps to different environmental conditions and suggest the existence of different habits related to the ambient conditions. Hosts (Figs 1 , 2 ). Undetermined species of the oriental armyworm Mythimna Ochsenheimer ( Noctuidae : Hadeninae , Leucaniini ). The living caterpillar was collected in the fifth instar. It took four days for Mythimna to die after the cocoons were detached from its body. In the living Mythimna caterpillar, the cocoons of M. idreesae were more clustered in the central part of the caterpillar body forming a dorsal band and a few were in the latero-posterior side (Fig. 1B ). In the dead caterpillar, the holes were observed in the dorsal, ventral, and lateral sides of the body (Fig. 2 ). Three potential food plant species were identified in the vicinity of the collected caterpillar, Ipomoea pes-caprae ( Convolvulaceae , bay-hops), Euphorbia serpens ( Euphorbiaceae , matted sandmat), and Cynodon dactylon ( Poaceae , bermudagrass). Molecular data. The partial nucleotide sequence of Cyt-b gene (381 bp) is available in the GenBank database, accession number: OP485682. Remarks. Morphological and distributional data that allow the separation of all the Microplitis species reported in the KSA is listed in Table 1 . Table 1. All Microplitis species from the Kingdom of Saudi Arabia displaying their morphological differences and distributional data.

-	M. faifaicus Ghramh & Ahmad, 2020	M. idreesae Arias-Penna & Al-Sabi, sp. nov.	M. khamisicus Ghramh & Ahmad, 2020	M. tihamicus Ghramh & Ahmad, 2020
Body size	2.5 mm	2.59 mm	3.0-3.1 mm	2.1-2.2 mm
Colour on body	Body generally black, T1 brown, palps and hind tibial spurs yellow, legs yellow except hind coxae	Body generally black, all legs dark yellow-brown except all claws dark brown and hind coxae with basal third dark brown, second third black, and distal third yellow-brown, T2 and anterior half of T3 yellow-brown	Body entirely dark brown to black excluding all legs and laterotergites dorsolaterally yellowish	Body entirely dark brown to black excluding yellowish legs
Colour on wings	Infuscate	Hyaline	Infuscate	Hyaline but slightly infuscate distally
Areolet shape	Quadrangular	Quadrangular	Quadrangular	Triangular
Shape of T1 posteriorly	Rounded/convex	Slightly elevated, rounded/convex	With a median knob	Truncate
Notauli	Weakly impressed, indicated only by narrow depressions postero-laterally	Well defined anteriorly but indistinct posteriorly	Well defined throughout	Weakly impressed, indicated only by narrow depressions postero-laterally
Medial furrow of mesoscutum	Absent	Present and incomplete	Present and complete	Absent
Setae in head and mesosoma	Moderately to sparsely setose	Moderately to sparsely setose	Densely setose	Moderately to sparsely setose
Distribution in the KSA	Faifa (Jazan Province)	Hofuf (Eastern Province)	Khamis Mushyat (Asir Province)	Abha, Almanaf (Asir Province)
Elevation (m)	906	154	1988	2226
Microplitis species to which it most resembles	M. hova (Granger, 1949) from Madagascar	M. albipennis (Abdinbekova, 1969) M. hispalensis (Marshall 1898), M. mandibularis (Thomson 1895), and M. spectabilis (Haliday, 1834) from the Palaeartic	M. bambusanus (de Saeger, 1944) from Congo and Rwanda	M. isis (de Saeger, 1944) from Congo

Microplitis idreesae is closely related to Palaeartic species that exhibit the T1 barrel-shaped with scarce sculpturing; the legs with a light coloration (at least moderately, as it can be variable) except the hind coxa; and the fore wing with pterostigma bicoloured (dark with a pale basal spot). Considering this, four Microplitis species look similar to M. idreesae . In alphabetic order, these are M. albipennis Abdinbekova, M. hispalensis Marshall, M. mandibularis Thomson, and M. spectabilis Haliday. Similarities and differences between M. idreesae from these species are listed below. Microplitis idreesae and M. albipennis. In both species the wings are hyaline, the fore wing with the 1-R1 vein short, half as long as the pterostigma, the position of the r vein is oblique concerning the pterostigma, and the r vein is only somewhat shorter than the 2-SR vein. Microplitis idreesae can be separated from M. albipennis by the following characters: 1) length of the T1: in M. albipennis is 1.6-1.7 times as long as broad, whereas in M. idreesae is 2.0 times as long as broad; 2) the colour on the tegula: in M. albipennis is black, whereas in M. idreesae is dark yellow-brown; 3) in the hind wings, the length of the 1-SR and 2M veins: in M. albippenis the 2-M vein hardly is 1.5 times longer than 1-SR, whereas in M. idreesae the 2-M vein is 1.7 times longer than 1-SR. Microplitis albipennis has been reported in Azerbaijan, Hungary, Mongolia, Poland, Russia, and Turkey ( Fernandez-Triana et al. 2020 ); and its lifestyle is unknown. Black/white line drawings of some structures are available on Papp 1984 (fig. 73, p. 123; figs 146, 147, p. 129). Microplitis idreesae and M. hispalensis. In both species the first antennal flagellomere is thrice longer than broad, further flagellomeres gradually shorten so that the penultimate is twice longer than broad; the precoxal sulcus is crenulate; and with gregarious lifestyle. Microplitis idreesae can be separated from M. hispalensis by the following characters: 1) female body size: in M. hispalensis the length is 3 mm, whereas in M. idreesae is 2.6-2.9 mm; 2) position of the r vein concerning the pterostigma: in M. hispalensis the vein r is perpendicular to the pterostigma, whereas in M. idreesae the vein r is oblique to the pterostigma; 3) colour on the body: in M. hispalensis is completely black, whereas in M. idreesae , females with T2 completely pale and T3 bicoloured (half anterior pale, half posterior dark), contrasting with the colour on the males, where the pale coloration is confined only to a small area, anterior corners of T2; 4) colour on the wings: in M. hispalensis is weakly smoky (famous), whereas in M. idreesae is hyaline; 5) colour on the legs: in M. hispalensis is black although, in males, the legs show a light pattern and more infuscation, whereas in M. idreesae the legs are completely dark yellow-brown, except the hind coxa with basal third dark brown, second third black, and distal third yellow-brown; 6) and in M. hispalensis the antenna is as long as the body, while in M. idreesae is antenna is longer than the body. Microplitis hispalensis has been reported in France and Spain ( Fernandez-Triana et al. 2020 ). Black/white line drawings of some structures are available on Papp 1984 (figs 141-144, p. 129). Microplitis idreesae and M. mandibularis . In both species, the fore and middle coxae are entirely yellow, and the hind coxa is frequently splashed with yellow, and with gregarious lifestyle. Microplitis idreesae can be separated from M. mandibularis by the following characters: 1) colour on T2 and T3: in M. mandibularis , sometimes the females display the T2 and the T3 very marked with yellow, whereas in M. idreeasae , the females with the T2 completely pale and the T3 bicoloured (half anterior pale, half posterior dark); 2) colour on the male antennal flagellomeres: in M. mandibularis they are pale throughout though this is sometimes more obvious on the underside, whereas in M. idreesae the pale colouration (yellow-brown) is clear in the first eight proximal antennal flagellomeres and gets gradually darker in the next two flagellomeres (9th and 10th) and become dark (dark brown or black) in the remaining flagellomeres; 3) the body length: in M. mandibularis , specimens are variable in size (2.4-3.2 mm), whereas in M. idreesae is 2.5-2.9 mm. Microplitis mandibularis has been reported in 19 countries from the Palaeartic and one country (Greenland) from the Nearctic region ( Fernandez-Triana et al. 2020 ). A black/white line drawing of the T1 is available in Nixon 1970 (fig. 1, p. 6). Microplitis idreesae and M. spectabilis . In both species the wings are often almost uniformly hyaline; the scutellum becoming strongly shining over most of its median surface and only vaguely sculptured; on the hind wing, the vannal lobe is small; the hind tibia without apical infuscation; gregarious lifestyle; the cocoon is oval, lacking any kind of remarkable ornament, the silk fibers look disordered and fluffy, the body length in M. spectabilis ranges between 2.6 to 2.8 mm, and in M. idreesae is between 2.5 to 2.9 mm; and setae of the metasoma somewhat inconspicuous, often restricted to a single row on the tergites. The two species can be separated by the following characters: 1) colour on the tegula: in M. spectabilis is yellow, whereas in M. idreesae is dark yellow-brown, 2) antennal flagellomeres length: in M. spectabilis are rather thick and somewhat smooth looking towards apex, whereas in M. idreesae are longer than wider and the pubescence are present along its entire surface; 3) length of the penultimate antennal flagellomere: in M. spectabilis it varies from one and one third to one and a half times longer than wide, whereas in M. idreesae is at least 2 times longer than wide, 4) antennal flagellomeres in the males: in M. spectabilis they are apparently always at least slightly paler beneath, whereas in M. idreesae the pale colouration (yellow-brown) is clear in the first eight proximal antennal flagellomeres and gets gradually darker in the next two flagellomeres (9th and 10th) and become dark (dark brown or black) in the remaining flagellomeres; 4) apex of the hind tibia: in M. spectabilis , seen from the side the hind tibia is a little broaden before apex, whereas in M. idreesae the apex is not broaden, and 5) position of the r vein concerning the pterostigma: in M. spectabilis the r is perpendicular to the pterostigma, whereas in M. idreesae the r is oblique to the pterostigma. Microplitis spectabilis has been reported in 36 countries from the Palaeartic region and there is also been recorded in the Oriental region (Pakistan) ( Fernandez-Triana et al. 2020 ). Black/white line drawings of some structures are available in Nixon 1970 (fig. 11, p. 9; fig. 25, p. 11) and Papp 1984 (figs 64-67, p. 123). Comments. As mentioned before, in 2017 one morpho-species was reported in the KSA ( Fernandez-Triana and van Achterberg 2017 ), but the only data associated were morpho-species number ( Microplitis sp. 6), numbers of females and males (2 females, 1 male), the collecting date (only the year, 1959), and the collecting site (Riyadh, the administrational center of Riyadh Province, located in the center of the country). Specimens are old, and not in particularly look conditions, without molecular data, and are currently deposited in the Canadian National Collection of Insects (CNC), Ottawa, Ontario, Canada (Fernandez-Triana, pers. commun.).