An overview of the genus Alaptus Westwood in India (Hymenoptera: Mymaridae)

Abstract The genus Alaptus Westwood (Hymenoptera: Mymaridae) is characterised by its minute-sized body with no visible petiole and deeply excised posterior margin of fore wing. Three new species are described from different Indian states or Union Territory: A. deodus Anwar & Zeya sp. nov. (Karnataka), A. spicatus Anwar & Zeya sp. nov. (Karnataka), and A. wandoorensis Anwar & Zeya sp. nov. (Andaman and Nicobar Islands). Two species, A. iceryae Riley (Karnataka) and A. terebrans Kryger (Karnataka), are recorded for the first time from India, albeit the identification of A. terebrans is tentative. Two Indian species are put under synonymy: A. jowainus Rehmat & Anis syn. nov. and A. pyronus Anwar & Zeya syn nov. under A. immaturus Perkins. As A. deccanensis Anwar & Zeya share most of its characters with A. fusculus Walker except its body and antennal sizes, so a comparative analysis of both the species is provided, but its synonymy with A. fusculus has not been proposed at present and it needs to be confirmed on the basis of molecular studies. A revised key to males and females of the Indian species is also provided. http://urn:lsid:zoobank.org:pub:09951D88-75A8-43FF-87A1-9CF8F230D096 http://urn:lsid:zoobank.org:act:76C5EDBD-0B0E-41E6-B92F-07F636AA868C http://urn:lsid:zoobank.org:act:1C55F240-BF4B-4954-A273-0CEB6D775B63 http://urn:lsid:zoobank.org:act:95744029-0947-4614-945B-350627CCE82A


Introduction
The genus Alaptus Westwood is cosmopolitan in distribution, mainly found in forested habitat but are often overlooked because of their minute size (Triapitsyn 2017). Even if found, they require an expert hand to handle and prepare for their species level identification. Annandale (1909) described the first species (A. magnanimus) from India, followed by the description of two species (A. delhiensis and A. ramakrishnai) from India by Mani (1942). After more than seven decades, Anwar and Zeya (2014), Rehmat and Anis (2014) and Anwar et al. (2015) studied the genus in India and described several species. Later, Triapitsyn (2017) revised the genus far the Holarctic region and provided notes on some extralimital species. He, also remarked that some of the Indian species described by Anwar and Zeya (2014) could prove to be synonymous with the Holarctic species. The genus Alaptus presently contains 43 world species, and 10 species from India, including the 3 new species described here, and two species newly recorded from India. The main aim of this study is to consider the remarks of Triapitsyn (2017), to record *Correspondence: S. B. Zeya, Department of Zoology, Aligarh Muslim University, Aligarh 202002, India. Email: drsbz1966@gmail.com The European Zoological Journal, 2022Journal, , 1159Journal, -1173Journal, https://doi.org/10.1080Journal, /24750263.2022 and describe some species of Alaptus from India and to provide an updated key to the Indian species of Alaptus Westwood.

Material and methods
The study is based on the material collected by using various traps from several Indian states. The collected specimens were initially stored in 80% ethanol and were later mounted on rectangular cards. Body colour and lengths were noted from card mounted specimens. Further identification slides were prepared following the method described in Noyes (1982), with modifications as mentioned in Anwar et al. (2020). The terminology used in the text follows Zeya and Hayat (1995) and Gibson (1997). The measurements, other than body lengths, are relative and taken from slide mounts. All the measurements are in micrometers (µm). The photographs of slide-mounted parts except Figures 4(b) and 6 were taken with a Leica® DFC295 digital camera attached to a Leica® DM 2500 compound microscope. The photographs of Figures 4 (b) and 6 were taken with a digital camera attached to a compound microscope "Nikon eclipse DM 2500". Photographic plates were prepared using Adobe Photoshop® 7.0. All the determined and type materials were deposited at the Insect Collections Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Diagnosis
. Alaptus deodus appears similar to Alaptus immaturus in having slightly exserted ovipositor, sculpture on frontovertex, frenum, and more or less similar antennal configuration. However, it differs from the latter mainly by the following characters (A. immaturus characters given in parentheses after Triapitsyn 2017): mesoscutum with rugose sculpture (mesoscutum with polygonal reticulations); fore wing with a complete row of setae (fore wing disc almost bare except 2-6 setae in the middle).
Based on the fore wing setation and antennal configuration A. deodus also comes close to another Holarctic species A. minimus Westwood from which it differs as follows (A. minimus characters given in parentheses after Triapitsyn 2017): scape 2.2-2.3× as long as broad (scape 2.7-3.4× as long as broad); clava distinctly long, subequal to F2-F5 combined (clava a little shorter than combined length of F3-F5); ovipositor 1.1-1.3× as long as mesotibia and, 1.5-1.6× as long as metatibia (ovipositor almost 1.6× as long as mesotibia and, 1.2-1.5× length of metatibia).
Etymology. The species name is an arbitrary combination of letters, and may be taken as a noun in apposition. Diagnosis. Alaptus spicatus is one of the most distinctive species that can be easily separated from all the other species in the genus by the following characters: head with vertex and mesoscutum with a pair of spine-like thick setae; each axilla with one long spine-like seta; axillary seta more than 2× as long as seta present on vertex and mesoscutum; fore wing with a pair of long and thick dorsal macrochaetae; posterior margin with a translucent membrane-like covering, hence not deeply curved. In other Alaptus species: head with vertex and mesoscutum with a pair of relatively thin setae and not spine-like; each axilla with relatively thin seta; fore wing with a pair of dorsal macrochaetae, relatively not thick, and posterior margin without membrane-like covering, hence deeply excised. While none of the Alaptus species have such long, spine-like setae on their head, body and fore wings.

Distribution. India: Karnataka.
Etymology. The species name is derived from a well-developed spine-like setae present on its head and mesosoma.

Diagnosis.
Alaptus wandoorensis is a distinct species with a very long and massive clava, rugosely sculptured vertex of head and mesosoma, with a long, curved and exserted ovipositor. It apparently comes close to the A. ramamurthyi Anwar and Zeya (2014) by having F2 the longest funicular segment; clava a little shorter than funicle; ovipositor strongly exserted beyond apex of gaster and, occupying the entire length of the gaster. However, it differs from the latter in the following characters (A. ramamurthyi characters given in parenthesis): frontovertex with rugose sculpture (frontovertex with transverse striations); antenna with scape 3× as long as broad; pedicel longer than all funicular segments individually except F2; clava 3.4× as long as broad (antenna with scape about 2× as long as broad; pedicel distinctly longer than all funicular segments individually; clava 4.5× as long as broad); mesosoma with rugose reticulate sculpture (mesosoma with polygonal reticulation).

Distribution. India: Andaman & Nicobar Islands.
Etymology. The species name is derived from the locality Wandoor beach of Andaman & Nicobar Islands from where the holotype was collected.

Diagnosis and comments.
Alaptus terebrans has ovipositor longer than entire length of metasoma and, strongly exerted beyond the apex of gaster, 1.3-1.6× as long as metasoma and, 2.1-2.3× as long as metatibia. The specimens identified here as A. ?terebrans agree fairly well with the redescription of the species provided by Triapitsyn (2017). However, there are slight differences in following features: antenna with scape 2.2-2.8× as long as broad (Figure 6(b)), pedicel subequal to F2, F2 the longest, 2.6-3× as long as broad, clava 3-3.6× as long as broad, longer than F3-F5 combined (antenna with scape 2.8-3.2× as long as broad, pedicel shorter than F2, F2 the longest, 4.0-5.0× as long as broad, clava 3.6-4.0× as long as broad, slightly longer than F3-F5 combined); fore wing 8-9× as long as broad, disc with a complete row of 13-15 setae (Figure 6(c)); hind wing 16-17× as long as broad (Figure 6(c)) (fore wing 7.8-8.7× as long as broad, disc with 15-17 setae in a complete row and 0 or 1 additional setae in the widest part just behind it, longest marginal seta 3.0-3.3× as long as maximum wing width; hind wing 15-17× as long as broad); ovipositor occupying the entire length of metasoma and strongly exserted beyond apex of gaster, exserted part 0.2-0.3× its own length (Figure 6(d)) (ovipositor occupying the entire length of metasoma and strongly exserted beyond apex of gaster, exserted part 0.32-0.35× its own length).
Though, A. terebrans is exclusively a Palaearctic species mostly confined to northern European region and biogeographically, it would be very unlikely for the species to occur in India. So, without having any supporting genetic evidence, we would not make a positive identification. Because, it shares most of its morphometrics and morphological characters with A. terebrans so, at most tentatively we call it A. ?terebrans. A better analysis of their differences needs to be presented, even if these are minor. All A. terebrans from Europe have at least 2 (up to 7) setae on the disc in addition of the complete row of setae next to anterior margin, and that is an important diagnostic feature which is lacking in our specimens from India.

Alaptus immaturus Perkins, 1905
Alaptus immaturus Perkins, 1905: 197    distinctly exserted beyond apex of gaster (ovipositor 1.7-1.8× as long as metatibia, distinctly exserted from apex of gaster). Apart from these differences, the other character that separates A. deccansesis from A. fusculus is the body size and length of funicle segments. The former being smaller 320 µm and its funicular segments relatively thick and stout, while the latter being a bit larger 400-500 µm with its funicular segments thin and long, otherwise both share the same relative measurements. However, the conspecificity of both the species cannot be determined without a handful support of molecular evidence.

Discussion
Among the three species described in this paper, Alaptus spicatus and A. wandoorensis are remarkable in the genus, the former has modified spine-like setae on its head, mesosoma and fore wings, while the latter has unique sculpture on its mesosoma. The other described species A. deodus though shares some features with A. immaturus and A. minimus but, can be separated on the basis of the characters mentioned in the key.
While A. immaturus, A. fusculus, A. minimus, and A. iceryae are relatively widespread in the world, although perhaps not in all the continents, but occurrence of A. terebrans is unlikely as it is exclusively found in Palaearctic region. The newly recorded species from India A. iceryae agrees fairly well with the redescription of the species provided by Triapitsyn (2017) and hence is conspecific to A. iceryae from Nearctic, Palaearctic and Neotropical regions. The other recorded species A. ?terebrans has smaller body size, somewhat less setose fore wings, and relatively short antennal configuration as compared to the Palaearctic species; hence, its identification is tentative, similar is the case with A. deccanensis that has been compared here with A. fusculus but could not be placed under synonymy because of lack of molecular evidence. Occurrence of smaller or larger specimens is possible in Mymaridae (Triapitsyn & Berezovskiy 2003). Consequently, there are several cases where the body size of a species varies viz., Arescon dimidiatus (Curtis) (600-700 µm); Camptoptera jthuberi . The other possible reason for variation in the body size is the climatic conditions. The colder regions (i.e., Holarctic, Nearctic, Neotropical and Palaearctic, etc.) tend to have larger individuals as compared to warmer regions (i.e., Oriental). The other Indian species A. jowainus Rehmat & Anis shares most of its features with A. immaturus Perkins is hereby put under synonymy with A. immaturus and, the tentative synonymy for A. pyronus Anwar & Zeya as remarked by Triapitsyn (2017) under A. immaturus is confirmed and is formally synonymised.