INTERNATIONAL JOURNAL OF ACAROLOGY https://doi.org/10.1080/01647954.2020.1819410 New data on two myrmecophilous laelapid mites (Acari: Mesostigmata: Laelapidae) in Western Siberia, Russia Omid Joharchi a, Olga S. Asyamova a, Alexander A. Khaustov a, Derek A. Uhey b, Aigerim K. Issakova a and Andrei V. Tolstikov a aInstitute of Environmental and Agricultural Biology (X-BIO), Tyumen State University, Tyumen, Russia; bSchool of Forestry, Northern Arizona University, Flagstaff, AZ, USA ABSTRACT ARTICLE HISTORY Gaeolaelaps glabrosimilis: and Holostaspis flexuosa are recorded for the first time in Western Siberia, Received 3 June 2020 Russia, collected from the ant species Lasius fuliginosus (Latreille) (Formicidae) and Camponotus hercu­ Accepted 27 August 2020 leanus (L.), respectively. Gaeolaelaps glabrosimilis is redescribed on the basis of adults and a detailed Published online 30 comparison of this species with the very closely related species Gaeolaelaps longichaetus is presented. September 2020 Moreover, notable variations are observed in some morphological characters of H. flexuosa. KEYWORDS Phoretic mites; Gamasina; taxonomy; parasitiformes; mutualism; ants Introduction Halliday 1994; Fain et al. 1995; Mašán 1998; Trach 2012, 2016; Joharchi and Babaeian 2014; Saeidi et al. 2019; Joharchi et al. The nests of social insects provide a favourable habitat for many 2019a, 2019b). A few species of this genus have been collected symbiotic species, which may be parasitic, mutualistic, phoretic, in association with ants (Zeman 1982; Beaulieu 2009; Walter and predatory, or commensal with their hosts. A large diversity of Moser 2010; Joharchi et al. 2019a). The present paper is part of symbionts in social insect nests are mites, which can impact the a project that aims to increase the knowledge of the mite fauna of success of their insect hosts (e.g., Vissa and Hofstetter 2017). Yet the Asian part of Russia (especially, that of Western Siberia), parti­ most mite species remain undescribed, and this lack of under­ cularly the poorly studied fauna of insect-associated species of standing obscures their ecological roles. Ants are highly organized mesostigmatid mites. Towards this aim, we record two myrmeco­ social insects that create microhabitats through nest construction philous laelapid mites species Gaeolaelaps glabrosimilis (Hölldobler and Wilson 1990). Organisms that live in association (Hirschmann, Bernhard, Greim and Götz, 1969) and Holostaspis with ants (i.e. myrmecophiles) are able to enter and access flexuosa (Michael, 1891) for the first time from Russia, which wer­ resources within nests, remaining largely undetected by the ant ecollected from the ant species Lasius fuliginosus (Latreille) and hosts. Myrmecophily is well-studied among Coleoptera, however, Camponotus herculeanus (L.), respectively. Gaeolaelaps glabrosimi­ mites are typically the most abundant symbionts in nests (Kistner lis is redescribed on the basis of adults. Furthermore, detailed 1979). Mites are believed to largely be communalistic or beneficial comparison of G. glabrosimilis with a very closely related species to their ant hosts (Eickwort 1990; Berghoff et al. 2009), confirmed Gaeolaelaps longichaetus (Ma, 1996) is presented. Moreover, parasitic relationships are rare (Franks et al. 1991). Instead, many we observe notable differences in some morphological characters myrmecophilous ants seem to take advantage of detritus or of West Siberian specimens of H. flexuosa in comparison with microbes in the nest, while using ant hosts for transportation to specimens from Slovakia, which have been presented by new habitats (i.e. phoresy) (Houck and OConnor 1991). Babaeian et al. (2019). A remarkable diversity of mites is found in association with ants, representing three major groups: the Mesostigmata, Prostigmata, and Astigmatina (Eickwort 1990). The family Laelapidae Materials and methods (Mesostigmata) is highly speciose and includes about 1,520 described species sorted into more than 146 genera (Keum et al. Host ants were collected from the nest in the forest using an 2017; Joharchi et al. 2018), with a rich ecological diversity not aspirator and placed in vials with 96% ethanol. Thereafter, alcohol found other families of Mesostigmata. Within the Laelapidae, sev­ sediments from the vials were inspected for detached ant- eral genera of the subfamily Hypoaspidinae have close associa­ associated mites. Mites were removed from ant nests by extraction tions with many insect groups, including ants (Eickwort 1990). from nest material using Berlese-Tullgren funnels. Specimens were Some of these genera are mostly or entirely myrmecophilous, cleared in lactic acid solution and mounted in Hoyer’s medium while others have various relationships with insects or none at (Walter and Krantz 2009). The line drawings and examinations of all. An example of the former is Holostaspis, an ant-associated the specimens were performed with a Zeiss Axio Imager A2 and genus intermediate between Laelaspis and Myrmozercon which Leica DM 2500 compound microscopes equipped with differential comprises 10 nominal species (Babaeian et al. 2019). In contrast, interference contrast and phase contrast optical systems, attached an example of the latter is Gaeolaelaps. Members of this large to cameras AxioCam ICc 5 and ICC50 HD, respectively. Figures genus, comprising more than 120 species, have been described were elaborated with Adobe Photoshop CS2 software based on from soil-litter habitats (Bregetova 1977; Karg 1993; Beaulieu the line drawings. Images and morphological measurements were 2009), nests of vertebrates (Tenorio 1982), or associated with taken via ZEN 2012 software (version 8.0) and Leica Application arthropods (or their nests), including mygalomorph spiders, milli­ Suite (LAS) software (version 4.2, Live and Interactive pedes, cockroaches, termites, as well as cerambycid, passalid, scar­ Measurements modules). Photomicrographs were taken with an abaeid, carabid and heterocerid beetles (Rosario 1981; Strong and AxioCam 506 camera (Carl Zeiss, Germany). Measurements of CONTACT Omid Joharchi [email protected] Institute of Environmental and Agricultural Biology (X-BIO), Tyumen State University, Tyumen, Russia © 2020 Informa UK Limited, trading as Taylor & Francis Group Published online 30 Sep 2020 2 O. JOHARCHI ET AL. structures are expressed as ranges (minimum–maximum) in micro­ three or four unpaired supernumerary setae Jx; most setae metres (μm). The length and width of the dorsal shield were taken smooth, J4, J5 and Z5 with 2–4 min barbs (Figure 1(a) and 2(a)); from the anterior to posterior margins along the midline, and at podonotal setae slightly shorter than opisthonotal setae. Shield level of r3, respectively. Length and width of the sternal shield with about 15 pairs of discernible pore-like structures, including were measured at the maximum length and broadest points (at nine poroids (id1, id2, id4, id5, idm1-3, idx, is1) and six gland open­ level of endopodal between coxae II and III), respectively. The ings (gd1, gd2, gd4-6, gd8). Shape, position and relative length of length of the genital shield was measured along the midline setae shown in Figure 1(a) and 2(a). from the anterior margin of the hyaline extension to the posterior margin of the shield, and its width where maximal, posteriorly to Ventral idiosoma genital setae st5. Leg length was measured from the base of the (Figure 1(b) and 2(b,c)). Tritosternum with paired pilose laciniae coxa to the apex of the tarsus (excluding the pre-tarsus). The (64–70), fused basally (10–12), columnar base 17–20 × 14–16 nomenclature used for the dorsal idiosomal chaetotaxy follows wide; presternal area with transverse lightly sclerotized lines that of Lindquist and Evans (1965), the notations for leg and palp (Figure 1(b) and 2(b,c)), fused to sternal shield. Sternal shield setae follow those of Evans (1963a, 1963b)), and other anatomical (length 100–105) narrowest between coxae II (100–107), widest structures mostly follow Evans and Till (1979). Notations for idio­ at level of endopodal between coxae II and III (159–168), poster­ somal pore-like structures (gland pores and poroids/lyrifissures) ior margin irregularly concave; with three pairs of long and and peritrematal shield follow mostly Athias-Henriot (1971, smooth sternal setae, (st1 (44–46), st2 (46–48), st3 (43–45)), reach­ 1975)). The notations for pore-like structures on the sternal shield ing well base of next posterior setae and two pairs of poroids (iv1 and for the peritrematal shield region also follow modifications and iv2 slit-like, adjacent to setae st1 and between st2 and st3, and additions by Johnston and Moraza (1991), adapted by Kazemi respectively) (Figure 1(b) and 2(b,c)); surface without reticulate et al. (2014). ornamentation, almost smooth, except some irregular longitudi­ nal lines laterally, shield fused anterolaterally to narrow endopo­ dal strip between coxae I and II, and to endopodal between coxae Systematics II and III. Metasternal setae st4 (44–46) and metasternal poroids Genus Gaeolaelaps Evans and Till, 1966Hypoaspis iv3 inserted on soft cuticle posterior to sternal shield; metasternal (Gaeolaelaps) Evans and Till 1966: 159. platelets absent. Endopodal plates II/III completely fused to ster­ nal shield, endopodal plates III/IV elongate, narrow, and curved. Type species Laelaps aculeifer Canestrini, 1884, by original desig­ Genital shield elongated, rounded posteriorly, slightly protruding nation (1966). at level between setae st5 and Zv1,