A new species of Ensliniella is described from deutonymphs from two localities in central Japan as the seventh species of the genus. Ensliniella asiatica sp. nov., found in the nests and acarinaria (mite chambers) of the vespid wasp Allodynerus mandschuricus, differs from the most similar species, E. kostylevi, in having a more reduced, shorter, subconical solenidion ϕ on tibia IV and ensiform setae e and r on tarsus III. It is readily distinguished from the remaining five known congeners in having a solenidion ω2 on tarsus I. This is the second species of Ensliniella known from Japan.
Vitzthum (1925) established the genus Ensliniella for a new wasp-associated astigmatid mite from Germany. Later, Zakhvatkin (1941) described a new species from Belarus and Ukraine, and Baker and Cunliffe (1960) reported two new species from Egypt and Morocco. More recently, Klompen and OConnor (1995) described a new species from Turkey and another from Croatia. Cooreman (1942) originally described yet another species, E. trisetosa, as a member of Ensliniella, but later (1954) established a monotypic genus, Kennethiella, for this species. In all, six species of Ensliniella, currently assigned to the subfamily Ensliniellinae in the family Winterschmidtiidae (OConnor, 1982, 1984), are known from the Palaearctic region. Klompen and OConnor (1995) not only documented the morphology and revised the taxonomy of Ensliniella, but inferred phylogeny and discussed the evolution of life history traits. Their taxonomic revision, however, was based primarily on material from the European and Mediterranean subregions, and species from other areas have been poorly studied. The only study available for the Manchurian subregion, for instance, is that of Makino and Okabe (2003), who examined E. parasitica Vitzthum, 1925 from central Japan.
Mites of the genus Ensliniella are obligatorily associated with mason wasps of the genus Allodynerus Blüthgen in the vespid subfamily Eumeninae, and are found on the body or in the nests of the hosts (Enslin, 1922; Vitzthum, 1925). Adults of Allodynerus have specialized structures called acarinaria, which are elaborate, deeply invaginated chambers that harbor the deutonymphs of Ensliniella (OConnor and Klompen, 1999; Makino and Okabe, 2003). The existence of such specialized structures as acarinaria suggests that the interactions between Allodynerus and Ensliniella are close, and this has long intrigued researchers (Enslin, 1922; Vitzthum, 1925; Cooreman, 1942; Benno, 1945; Crèvecoeur, 1945; Cooper, 1955; Giordani Soika, 1987; Klompen et al., 1987; Klompen and OConnor, 1995; OConnor and Klompen, 1999; Makino and Okabe, 2003). Nonetheless, no one has explained why species of Allodynerus develop and retain acarinaria (OConnor and Klompen, 1999; Makino and Okabe, 2003). To advance our understanding of this phenomenon, it is necessary not only to evaluate the diversity of Ensliniella species, but also to understand their associations with Allodynerus in an evolutionary context.
Recently, we obtained deutonymphs of an astigmatid mite associated with an Asian eumenine, Allodynerus mandschuricus Blüthgen, 1953, from Saitama and Kyoto Prefectures in central Japan. In a taxonomic paper on Allodynerus, Blüthgen (1953) mentioned an Ensliniella on A. mandschuricus from China but did not identify it to species. After a detailed examination of these mites from Japan, we concluded that they represent an unnamed species of Ensliniella, which we describe here.
MATERIALS AND METHODS
We used trap nests to collect wasps of Allodynerus mandschuricus that harbor the new species of Ensliniella. At the collection site in Saitama Prefecture, we used a trap nest of bamboo internodes, whereas at the collection site in Kyoto Prefecture, we used a bunch of internodes of the common reed Phragmites australis (Cav.) Trin. ex Steud. (Yamane, 1990). We detached the mites carefully from the trap nest or from the body surface of wasps using a minute pin under a dissecting microscope and preserved them in a vial with 99% ethyl alcohol.
Specimens for light microscopy were incubated at 40°C in lactophenol solution mixed with a small amount of Nesbitt's fluid (40 g chloral hydrate, 25 ml distilled water, 2.5 ml concentrated hydrochloric acid) (Krantz, 1978) to clear the body, and were then mounted individually on glass slides in Hoyer's medium (Krantz, 1978). As in previous studies, specimens were flattened dorsoventrally by gently pressing the cover slips. After the medium dried completely, cover slips were sealed with Glyptal® , a suitable alkyd for ringing (Travis, 1968). Specimens were examined at 1000×magnification under a compound microscope with phase contrast and Nomarski differential-interference contrast optics (Nikon E600), illustrated using a camera lucida, and photographed with a digital camera attached to the microscope. Other specimens were mounted on a stub with double-sided carbon tape and observed and photographed with a scanning electron microscope (Keyence VE-8800) under an acceleration voltage of 1.3 kV.
Morphological characters to be measured were chosen following Klompen and OConnor (1995). The holotype and nine randomly selected paratypes were measured by first tracing characters on paper using a camera lucida, and then digitizing the traces with a scanner and calibrating and measuring them by means of a graphic pen tablet and the freeware program ImageJ version 1.33l (Rasband, 1997–2004; http://rsb.info.nih.gov/ij). For terminology, we primarily followed the idiosomal chaetotaxy of Griffiths et al. (1990) as modified by Norton (1998) and Okabe and OConnor (2002) and the leg chaetotaxy of Grandjean (1939), and for other characters followed Klompen and OConnor (1995). For comparison, we examined various specimens of the six known species of Ensliniella deposited in the Forestry and Forest Products Research Institute, Tsukuba (FFPRI).
The holotype is deposited in the Natural Resources Inventory Center, National Institute for Agro-Environmental Sciences, Tsukuba (NIAES). Paratypes are deposited in NIAES; the Museum of Biological Diversity, Ohio State University Acarology Laboratory, Columbus (OSAL); and the Museum of Zoology, University of Michigan, Ann Arbor (UMMZ). Voucher specimens of the host wasp, Allodynerus mandschuricus, are deposited in FFPRI.
Ensliniella asiatica sp. nov.
[Japanese name: Ajiakita-dorobachi-yadori-konadani, new]
Morphometric data of deutonymph Ensliniella asiatica sp. nov.
Holotype (slide specimen): deutonymph (NIAES 440000001); Sakurazawa, Yorii town, Osato District, Saitama Prefecture, central Honshu, Japan; 36°07′49″N, 139°12′28″E; 102 m elevation; collected from nest of vespid wasp Allodynerus mandschuricus (collection no. OKBH05-0819-004) on 19 August 2005 by T. Nambu. Seventeen paratypes (slide specimens): deutonymphs (NIAES 440000002–440000018), locality same as holotype, collected from nest and body of A. mandschuricus (OKBH05-0819-004). Four paratypes (dry specimens on a stub for scanning electron microscope): deutonymphs (NIAES 440000039), locality same as holotype, collected from nest and body surface of A. mandschuricus (OKBH05-0819-001-1). Thirteen paratypes (slide specimens): deutonymphs (NIAES 440000019–440000038, OSAL 14396–14400, UMMZ 06-1001-001–005); Naka, Miyama town, Kitakuwata District, Kyoto Prefecture, western Honshu, Japan; 35°18′33″N, 135°38′13″E; 258 m elevation; collected from body of adult female A. mandschuricus (OKBH03-1300-058) in July 2002 by T. Endo.
The specific name, asiatica (Asian), is a Latin adjective in the nominative case, nomen in supposition, referring to the presumed geographic distribution of the new species (see Discussion).
Description of holotype
Deutonymph. Body ovoid, large, depressed dorsoventrally (Fig. 1; see Table 1 for moprhometric data); color in life whitish and in preserved material faintly brownish-yellow. Dorsum almost completely covered by propodosomal and opisthosomal shields (Fig. 1A). Sejugal furrow distinct. Propodosomal shield subtriangular, covered thoroughly with shallow, reticulate striae (Figs. 1A; 2A, C). Opisthosomal shield trapezoidal, as broad as long, striated throughout (Figs. 1A; 2B, C); most striae transverse anterior to seta d1 and oblique or longitudinal posterior to seta d1 (Figs. 1A, 2C). Area among striae on propodosomal and opisthosomal shields evenly and densely punctate (Fig. 2A, B), except for anterolateral peripheral area of propodosomal shield, which is sparsely punctate or smooth; small, transverse area on propodosoma between seta scx and coxa I punctate and sclerotized; punctation composed of minute, mostly polygonal spots. Posterior dorsal apodeme on opisthosomal shield conspicuous; anterior projection short, not reaching level of setae h1. Ocelli large, subreniform, situated on anterior edge of propodosoma, with heavily pigmented retina (Fig. 1A); ocelli on both sides situated close to each other. Propodosomal setae scx, se, si, and vi simple, filiform, short; setae se and si inserted on propodosomal shield, setae scx and vi not inserted on the shield. Opisthosomal setae simple, filiform, short (except for setae cp and h3, which are long). Cupules ia, im, and ip subcircular, ia and ip similar in size, im smaller; opisthosomal gland gla present.
Venter smooth, largely occupied by coxal fields (Fig. 1B). Gnathosomal solenidion α long, stiff; gnathosomal seta (gs) filiform, long, 0.8 times as long as solenidion α (Table 1). Seta c3 simple, short, filiform. Attachment organ ovate, with slightly elevated margin (Fig. 1B); median sucker (ad1+2) and anterior sucker (ad3) subcircular in ventral view, the former much larger than the latter; ps1 and ps2 well-developed, subconical, similar in size, posterior and lateral to median sucker, respectively; unpaired and paired circular suckers developed posteroperipherally; posterior coxal apodeme IV and apodeme of attachment organ not fused. Genital papilla 2-segmented; basal segment subcylindrical, apical segment subconical with elongate tip. Seta g short, filiform.
Legs mostly punctate, similarly to dorsal shield. Leg segments free. Legs I and II elongate and well-developed, legs III and IV short and stout (Figs. 1B, 3). Leg apodemes distinct; coxal apodemes I fused medially, forming long sternum; anterior coxal apodeme II and coxal apodeme III not fused; posterior coxal apodemes II elongate, almost touching coxal apodeme III. Posterior ventral apodeme weakly flanged, long, extending beyond level of setae 4a. Coxa I with alveolus of seta 1a; coxa II glabrous; coxa III with alveolus of seta 3b; seta 4b long, filiform, developed on junction of anterior coxal apodeme IV and posterior ventral apodeme; coxa IV with minute seta 4a. Trochanters I–IV, especially III and IV, short and stout; trochanters I and II each with filiform seta pR; trochanter III with filiform seta sR; trochanter IV glabrous. Femora I and II each with long, filiform seta vF ventrally; femur IV with short, filiform seta wF ventrally; femur III glabrous. Genua I and II well-developed, as long as wide; genu I proximally with short setae cG and mG and distally with solenidia σ1 and σ2; solenidion σ1 spiniform, with subacute tip; solenidion σ2 minute, spiniform; these solenidia situated close to each other, with common, distinct alveolus. Genu II with setae cG and mG, which are similar in shape, size, position to those on genua I; solenidion σ1 spiniform, its tip subacute, longer and stouter than solenidion σ1 on genu I; solenidion σ2 absent. Genu III short, compressed, with short, thin seta nG; genu IV glabrous, strongly compressed. Tibiae I and II well-developed, slightly longer than wide; setae gT and hT short, filiform, the former longer than the latter; solenidion ϕ long, stiff, tapering gradually to subacute tip, with distinct alveolus. Tibia III compressed; seta kT short, filiform; solenidion ϕ stiff, tapering gradually to subacute tip, shorter than those on tibiae I and II. Tibia IV strongly compressed, with short, thin, filiform seta kT and strongly reduced, subconical solenidion ϕ. Tarsus I elongate; solenidion ω2 vestigial, papillate, developed proximally, with distinct, subcircular alveolus (Figs. 3A, 4A); solenidion ω1 stiff, subisodiametric, with round tip, situated proximally, anterior to solenidion ω2; famulus ε spiniform with subacute tip, developed from alveolus of solenidion ω1; seta wa thin, filiform; solenidion ω3 stiff, tapering gradually to subacute tip; seta d long, filiform, with large, subcircular alveolus; seta e short, filiform, developed from alveolus of seta d; setae f, la, ra lanceolate, situated distally, similar to one another in size and shape. Tarsus II elongate; solenidia ω2 and ω3 absent; solenidion ω1 stiff, subisodiametric, with round tip, situated proximally; famulus ε absent; seta wa thin, filiform; seta d long, filiform, with large, subcircular alveolus; seta e short, filiform, developed from alveolus of seta d; setae f, la, ra lanceolate, developed distally. Tarsus III normally compressed for the genus, length 1.3 times width (Table 1); seta d long, filiform; seta p stout, subconical; seta s short, elongate apically, swollen basally; setae f and w lanceolate, setae e and r ensiform. Tarsus IV subconical; seta d extremely long, filiform, developed dorsally, based on subconical projection; seta w filiform, long but much shorter than seta d; seta s short, spiniform; seta r a blunt spine; seta p stout basally, attenuate distally. Pretarsi I–III terminating in robust, hooked claws; leg IV without pretarsus and claw; tip of tarsus IV pointed.
Notes on paratypes
Deutonymphs. Opisthosomal shield as long as or slightly longer than wide (see Table 1 for morphometric data). Anterior projection of posterior dorsal apodeme always short, never reaching level of setae h1. Posterior coxal apodemes II always elongate, almost fused to coxal apodemes III. Posterior ventral apodeme long, clearly extending beyond level of setae 4a; always weakly flanged. Solenidion ω2 on tarsus I vestigial. Tarsus III always normally compressed. Solenidion ϕ on tibia IV subconical, strongly reduced.
Discussion of similar species
Species of Ensliniella have six ontogenetic stages: egg, larva, protonymph, deutonymph, tritonymph, and adult (Klompen et al., 1987). Both the deutonymphs and adults have been described for E. parasitica, (Vitzthum, 1925), and all stages but tritonymphs have been described for E. kostylevi, (Klompen et al., 1987), but the other four species are known only from phoretic deutonymphs (Klompen and OConnor, 1995). Likewise, we were able to collect only deutonymphs of E. asiatica sp. nov.; hence, the following discussion is applicable only to this stage.
Ensliniella includes six valid species (Klompen and OConnor, 1995): E. aegyptiana Baker and Cunliffe, 1960; E. dignotus Klompen and OConnor, 1995; E. floricola Klompen and OConnor, 1995; E. koenigi Baker and Cunliffe, 1960; E. kostylevi Zakhvatkin, 1941; and E. parasitica. Ensliniella asiatica sp. nov. is readily distinguished from all of these except E. kostylevi in having solenidion ω2 on tarsus L. Ensliniella asiatica sp. nov. most resembles E. kostylevi, known from the European and Mediterranean subregions of the Palaearctic region, in having solenidion ω2 on tarsus I (Figs. 3A, 4A) and elongate posterior coxal apodemes II, which almost reach coxal apodeme III (Fig. 1B). Although Zakhvatkin (1941) did not mention solenidion ω2 on tarsus I in the original description of E. kostylevi, Klompen et al. (1987) found this solenidion on specimens from various localities in Europe (see also Klompen and OConnor, 1995). Moreover, Zakhvatkin (1941) described three lanceolate setae on tarsus III; however, according to Klompen et al. (1987), a seta was overlooked in the original description, and the correct number of the setae is four. Unfortunately, Klompen et al. (1987) were unable to examine type specimens of E. kostylevi in removing these ambiguities, because the type specimens are lost. We nevertheless consider the corrections by Klompen et al. (1987) to be appropriate for the following reasons. First, all works other than Zakhvatkin (1941) report four rather than three lanceolate setae on tarsus III. Second, we confirmed that the alveolus on solenidion ω2 of tarsus I is present also in all deutonymphs identified as E. kostylevi phoretic on Allodynerus rossii (Lepeletier, 1841) from Steiermark in Austria. Ensliniella asiatica sp. nov. is distinguishable from E. kostylevi in having a more reduced, shorter, subconical solenidion ϕ on tibia IV (Figs. 3D, 4B) and ensiform setae e and r on leg III (Fig. 3C); these setae are lanceolate (their bases are more sharply tapering and slender) in E. kostylevi (see Fig. 5f of Klompen et al., 1987).
Ensliniella asiatica sp. nov. is known from the type locality in Saitama Prefecture and a locality in Kyoto Prefecture, both in central Japan. Geographic distributions between species of Allodynerus and their associated Ensliniella correspond reasonably well (>Klompen et al., 1987; Klompen and OConnor, 1995). Allodynerus mandschuricus, host of E. asiatica sp. nov., is known also from northeastern China and South Korea (Blüthgen, 1953; Giordani Soika, 1970; Yamane, 1990). Accordingly, we expect E. asiatica sp. nov. to be found in these regions of the Asian continent through further studies. In fact, Blüthgen (1953) mentioned Ensliniella associated with A. mandschuricus from Harbin in northeastern China. Although he did not identify the mites, considering the high host specificity in Ensliniella, we suspect that the mites reported by Blüthgen (1953) might be E. asiatica sp. nov.
Ensliniella asiatica sp. nov. is the second species of the genus from Japan; E. parasitica was previously reported from Ibaraki and Nagano Prefectures in central Honshu (Makino and Okabe, 2003). The hosts of these mite species are Allodynerus mandschuricus and A. delphinalis, respectively. Because these are the only two species of Allodynerus known from Japan (Yamane, 1990), we do not expect any new Ensliniella from this country.
We thank T. Nambu, T. Endo (Kobe College), and Sk. Yamane (Kagoshima University) for donating Allodynerus wasps; S. Makino (FFPRI) for help and advice; and H. Klompen (OSUM) and two anonymous reviewers for comments on the manuscript.