Insectolaelaps latopini ( Hirschmann & Wiśniewski, 1982 )

Insectolaelaps latopini ( Hirschmann & Wiśniewski, 1982)

( Figures 28–36 View FIGURE 28 View FIGURE 29 View FIGURE 30 View FIGURE 31 View FIGURE 32 View FIGURE 33 View FIGURE 34 View FIGURE 35 View FIGURE 36 )

Insectolaelaps pini ( Hirschmann, 1960) .— Shcherbak, 1980: 196 (only female). Misidentification.

Dendrolaelaps (Insectolaelaps) latopini Hirschmann & Wiśniewski, 1982: 36 .

Dendrolaelaps (Insectolaelaps) latopini .— Wiśniewski, 1984: 120.

Diagnosis

Idiosoma suboval, with setae mostly thin and short, similar in length; setae r2 and r3 on soft integument in deutonymph. Dorsal and ventral shields reticulate and densely micropunctate, at least in lateral parts. In females sternal setae st3 somewhat thicker than others, with conspicuously adjacent bases. Genital shield with a small marginal notch in posterolateral corner. Ventrianal shield with four pairs of opisthogastric setae (Jv1–Jv3, Zv2), widened in anterior part, with distinct punctation near anus. Peritremes of adults short and not reaching anterior margins of coxae III. Movable cheliceral digit with six to seven teeth in females and five to six teeth in deutonymphs; male spermatodactyl thin, curved and almost as long as movable chela. Genu III and tibia III with seven setae each and only one anterolateral seta; genu IV and tibia IV without conspicuously elongated dorsal setae. Male legs II and IV spurred, as in Figs 34A–D View FIGURE 34 ; subapical spur of tarsus II unusually robust, with rounded apex.

Redescription

Female ( Figs 28A View FIGURE 28 , 29–31A, 31C View FIGURE 29 View FIGURE 30 View FIGURE 31 , 32A, 32D View FIGURE 32 , 33A View FIGURE 33 , 34E View FIGURE 34 , 36B, 36C View FIGURE 36 ). Dorsal idiosoma ( Fig. 29 View FIGURE 29 ). Idiosoma 450–575 μm long, 270–345 μm wide (n = 10), dorso-ventrally flattened, elongate, suboval, largely covered by two dorsal shields. Podonotal shield 220–275 μm long, 250–320 μm wide, semicircular, convex anteriorly, moderately curved laterally and almost straight or slightly convex posteriorly, with four small and rounded medial scleronodules between setae j5 and j6, very fine punctation on weakly reticulate surface and 22 pairs of setae (j1–j6, z1–z6, s1–s6, r2–r5), of which r3 usually located ventrally on peritrematal part of the shield. Opisthonotal shield 240–305 μm long, 235–315 μm wide, semicircular, widest at level between setae S1 and S2, with straight to slightly convex anterior margin, curved lateral margins slightly expanded ventrally, well-rounded posterior margin, punctate-reticulate surface (reticulation better indicated in anterolateral areas between setae J1–J3 and Z1–Z3 and predominated by transverse lines at level between setae J3 and J4), and a curved row of dots between setae Z5; 20 pairs of opisthonotal setae, of which only R 1 is located on the soft integument outside the shield. Most dorsal setae relatively short and thin, needle-like and similar in length, except for short setae z1, R 1, R 2 and J5, and elongate whip-like setae Z5 and S5. Lengths of selected dorsal setae: j1, j5 and j6 20–26 μm, j2 and j4 25–31 μm, j3 29–35 μm, z1 13–17 μm, z5 23–28 μm, s1 19 –24 μm, s5, s6 and r3 28–35 μm, J1–J4 20–26 μm, J5 11–15 μm, Z1–Z3 29–36 μm, Z4 20–25 μm, Z5 90–110 μm, S1– S4 27 –35 μm, S5 105–135 μm, R 1 and R 2 10–15 μm, R 3 14–18 μm, R 4 19–24 μm, R 5 27–36 μm.

Ventral idiosoma ( Figs 28A View FIGURE 28 , 30 View FIGURE 30 , 31A View FIGURE 31 , 32A View FIGURE 32 ). Tritosternum normal for the genus. Presternal plates weakly sclerotized, transversely striate and separately connected to anterolateral margins of sternal shield ( Fig. 31A View FIGURE 31 ). Sternal shield 78–97 μm long in its better sclerotized part, 75–90 μm wide at the narrowest part between coxae II, with well-developed anterolateral and lateral corners, undulate and slightly concave anterior and well concave posterior margins; surface completely and finely punctate like other ventrally located scutal structures, with reticulation better indicated in marginal areas and usually absent in posteromedial part; four pairs of sternal setae (st1–st4) and three pairs of slit-like lyrifissures (iv1–iv3), of which st1 located on weakly sclerotized anterior part of shield; sternal setae st1–st4 similar in length, but st3 slightly thicker than others ( Fig. 30 View FIGURE 30 ), with following distances between them: st3↔ st3 (28–39 μm) <st1↔st1 (62–71 μm) <st2↔st2 (74–86 μm) ≤ st4↔st4 (78–98 μm). Epigynal shield elongate, 105–135 μm long, 83–112 μm at widest point behind genital setae (st5) and 54–69 μm at narrowest point in anterior part between coxae IV, with convex hyaline anterior margin reaching level of setae st4, straight lateral margins, straight to slightly convex posterior margin, a pair of small incisions in posterolateral corners, faint reticulate pattern predominated by longitudinal lines in anterior and posterolateral parts, and a pair of setae on posterolateral margins ( Fig. 30 View FIGURE 30 ); genital lyrifissures (iv5) on soft integument near posterolateral corners of shield. Ventrianal shield ( Fig. 32A View FIGURE 32 ) longer than wide, 167–235 μm long and 120–172 μm wide, convex anteriorly and posteriorly, concave laterally, conspicuously widened in anterior part and moderately narrowed posteriorly, with a slight notch near bases of Jv1, four pairs of opisthogastric setae (Jv1–Jv3, Zv2; of which Jv1 and Zv2 on shield margin) and three circumanal setae; almost entire surface reticulate, except for punctate area in posteriormost part near anus; circumanal setae similar in length (ad 29–40 μm, pa 26–36 μm); posterior margin connected to opisthonotal shield; cribrum with two transverse rows of denticles. Endopodal platelets III/IV free, small and subtriangular. Exopodal platelets fused into a narrow strips, free of peritrematal shields except for their posterior tips. Peritrematal shields narrow, free over almost entire length including poststigmatic part, connected to podonotal shield between setae r2 and r3; peritremes short, 71–117 μm long, with anterior tip between setae r4 and r5. Two pairs of metapodal platelets present; larger platelets narrow and long, usually 28–46 μm long, fusiform, with anterior and posterior angles bluntly pointed and a wormlike appendage connected to anterior margin; smaller platelets minute, slit-shaped. Soft opisthogastric integument with three pairs of setae (Jv5, Zv1, Zv3). All sternal and opisthogastric setae similar to those on dorsum, except for slightly thicker st3, with following lengths: st1 24–31 μm, st2 and st3 22–29 μm, st4 20–27 μm, st5 24–28 μm, Jv1 19–25 μm, Jv2 22–27 μm, Jv3 25–33 μm, Jv5 35–45 μm, Zv1 18–23 μm, Zv2 and Zv3 22–30 μm.

Sperm induction system ( Fig. 31C View FIGURE 31 ). Normal for genus, with a pair of well-sclerotized spherical structures, each adjacent to inner margin of coxa IV and bearing two tubular projections; projection often variously curved, only rarely straight as in Fig. 31C View FIGURE 31 , somewhat thicker in basal part and 30–55 μm long.

Gnathosoma ( Figs 32D View FIGURE 32 , 33A View FIGURE 33 , 36B, 36C View FIGURE 36 ). Deutosternal furrow normal for genus, with five transverse rows of many denticles connected laterally by slightly undulate longitudinal lines ( Fig. 32D View FIGURE 32 ); posteriormost row widest and extending beyond longitudinal lines; corniculi well sclerotized and spaced, horn-like, divergent to each other; internal malae apically pointed, with densely fimbriated outer margins and reaching beyond corniculi. Hypostomal setae smooth and needle-like, usually with attenuated apical part in h1 and h3; setae h2 shortest and h3 longest (h1 35–43 μm, h2 12–17 μm, h3 46–56 μm, pc 22–30 μm). Middle article of chelicerae relatively short and broad, with similar width along entire length, 125–138 μm long ( Fig. 33A View FIGURE 33 ); digits relatively robust, movable digit 52–59 μm long, with well-developed terminal hook and six, more often seven teeth (rarely eight teeth), including the largest and most proximal one; fixed digit with bidentate terminal hook, one distal tooth and laterally located row of three larger medial teeth, followed by usually 3–5 smaller proximal teeth; pilus dentilis short and thin; dorsal cheliceral seta short, hyaline and barely observable; arthrodial membrane well developed, usually with a row of several spines near ventral base of movable digit. Anterior margin of epistome triramous; all processes thin and similar in size, slightly spatulate and spiny in their apical part ( Figs 36B, 36C View FIGURE 36 ).

Legs ( Figs 28A View FIGURE 28 , 34E View FIGURE 34 ). All legs shorter than idiosoma, with well-developed pretarsus and ambulacral apparatus including pulvillus and two claws; pulvillus and claws of legs I smaller than those of other legs; legs I longer or similar in length to legs IV; dorsal scutal surface of coxae I obliquely cleft, with interspace of soft cuticle ( Fig. 28A View FIGURE 28 ) and a row of several denticles on anterior margin; anterior margin of coxae II with a sharp spine; legs I 365–415 μm, legs II 295–355 μm, legs III 265–315 μm, legs IV 330–410 μm long. Chaetotaxy of the legs: leg I—coxa (2), trochanter 1-1/3-1 (6), femur 2-3/1, 2/3-2 (13), genu 2-3/2, 2/1-2 (12), tibia 2-3/2, 2/1-2 (12); leg II—coxa (2), trochanter 1-0/3-1 (5), femur 2-3/1, 2/2-1 (11), genu 2-3/1, 2/1-2 (11), tibia 2-2/1, 2/1-2 (10); leg III—coxa (2), trochanter 1-1/3-0 (5), femur 1-2/1, 1/0-1 (6), genu 1-2/1, 2/0-1 (7), tibia 1-1/1, 2/1-1 (7); leg IV—coxa (1), trochanter 1-1/3-0 (5), femur 1-2/1, 1/0-1 (6), genu 1-2/1, 2/0-1 (7), tibia 1-1/1, 2/1-1 (7); tarsi II–IV with 18 setae; genu III with only seven setae (al2 and pv1 absent), tibia III with only seven setae (al2 absent). Leg setae smooth and thin, mostly needle-like, except for some slightly thickened dorsal setae of femora II–IV and genua III–IV, including spine-like seta pd2 on genua III and IV ( Fig. 34E View FIGURE 34 ), conspicuously shortened and thickened apicoventral setae (av1, pv1) on tarsi II–IV, elongated and distally attenuated whip-like setae ad2 on tarsi II–IV (ad2 unusually oriented perpendicular to tarsal axis).

Male ( Figs 28B View FIGURE 28 , 31B, 31D View FIGURE 31 , 32E View FIGURE 32 , 33B View FIGURE 33 , 34A–D View FIGURE 34 , 36D, 36E View FIGURE 36 ). Idiosoma 405–535 μm long, 245–350 μm wide (n = 10; Fig. 28B View FIGURE 28 ). Podonotal shield 215–275 μm long and 245–350 μm wide, laterally fused with peritrematal shield, located on anterolateral margins of venter; opisthonotal shield 195–270 μm long and 245–340 μm wide, extensively united laterally and posteriorly with ventral shield. All dorsal setae on podonotal and opisthonotal shields, including marginal setae R 1– R 5. Sternitogenital shield as in Fig. 31B View FIGURE 31 , 180–245 μm long, with well-developed endopodal corners between coxae II–III and III–IV, completely punctate, with reticulate pattern on anterior and medial parts, and four pairs of similar sternal setae (st1 24–29 μm, st2–st4 18–27 μm); genital setae (st5) on triangular plates adjacent to posteriormost part of sternitogenital shield, each plate with several longitudinal lines on surface and inner posterior margin connected to posterior margin of sternitogenital shield. Anterior margin of ventral shield widely convex and deeply notched behind coxae IV, each notch narrow, long, diagonally directed and ending near bases of setae Jv1; shield with the same number of opisthogastric setae as in female. Peritrema as in Fig. 31D View FIGURE 31 , similar to that of female. Ventral gnathosoma with similar features as in female ( Fig. 32E View FIGURE 32 ), but relatively shorter and broader than in female; length of rostral setae as follows: h1 21–28 μm, h2 11–16 μm, h3 50–58 μm, pc 31–37 μm. Middle article of chelicerae similar in proportions to that of female, 113–129 μm long; movable digit 43–52 μm long, regularly curved distally, with well-developed terminal hook, large submedial tooth and spermatodactyl; spermatodactyl about as long as fixed digit, narrow and long (47–55 μm long), slightly narrowed towards terminal part, moderately curved in distal part, apically rounded or bluntly pointed, with proximal part directed anteriorly and obliquely downwards and most distal part towards midline; sperm duct relatively wide, open near apex and located approximately along the central axis of spermatodactyl; fixed digit with short terminal hook, distal tooth and small pilus dentilis ( Fig. 33B View FIGURE 33 ). Epistome as in Figs 36D and 36E View FIGURE 36 , similar to that of female. Legs II spurred ( Figs 34A–D View FIGURE 34 ): femur, genu, tibia and tarsus with anteroventral seta modified into robust and superficially striated spur (femur), or with strongly sclerotized structure shaped as small and hemispherical tubercle (genu, tibia, tarsus); ventral telotarsus II with conspicuous, almost tubular and apically rounded projection in distal part, apparently more pronounced than in its proximal part ( Figs 34C, 34D View FIGURE 34 ). Proximal segments of legs IV also spurred ( Figs 34A, 34B View FIGURE 34 ): posteroventral distal margin of coxa with inconspicuous, rounded, petal-like projection and row of denticles behind this projection; anterodistal margin of trochanter with rather large and bluntly pointed spur, posterodistal margin of trochanter with small swelling; and medial posteroventral surface of femur also with conspicuous and bluntly pointed spur (spur of femur almost as large as that on trochanter); spurs of legs IV clearly reduced in size in small individuals; sexual dimorphism of dorsal setae of legs IV only weakly pronounced: ad2 of femur IV spine-like and together with pd2 on common bump-like projection ( Fig. 34B View FIGURE 34 ). Other characteristics as in female.

Deutonymph ( Figs 28C View FIGURE 28 , 32B, 32C, 32F View FIGURE 32 , 33C View FIGURE 33 , 35 View FIGURE 35 , 36A, 36F, 36G View FIGURE 36 ). Dorsal idiosoma ( Fig. 35 View FIGURE 35 ). Idiosoma 385– 455 μm long, 230–305 μm wide (n = 10), elongate, suboval, covered by two dorsal shields and with the same number of setae as in adults; in mature deutonymphs probably before molting, idiosoma conspicuously expanded laterally, subcircular, not completely covered by the shields. Podonotal shield 195–240 μm long, 200–250 μm wide, subpentagonal, with indistinct or only faintly indicated medial scleronodules at level between setae j5 and j6 and 20 pairs of setae (lacking r2 and r3, both on soft integument outside shield). Opisthonotal shield 188–222 μm long, 195–245 μm wide, with straight to slightly convex anterior and lateral margins, well-rounded posterior margin and similar setation as in female, except for presence of four pairs of marginal setae ( R 2– R 5 on soft integument adjacent to lateral margins of shield). Surface of both dorsal shields with similar ornamentation as in female. Dorsal setae mostly thin and needle-like, only Z5 and S5 elongated and whip-like as in adults. Soft integument densely striated. Lengths of selected dorsal setae as follows: j1 12–17 μm, j2 and j4–j6 16–24 μm, j3 23–29 μm, z1 9–13 μm, z5 18–23 μm, s5 24 –31 μm, s6 28 –35 μm, r3 24–32 μm, J1–J3 15–21 μm, J4 13–18 μm, J5 6–10 μm, Z1 and Z2 24–30 μm, Z3 22–27 μm, Z4 15–20 μm, Z5 105–135 μm, S1 and S3 23 –29 μm, S2 28 –35 μm, S4 19 –25 μm, S5 120–140 μm, R 1– R 3 7–14 μm, R 4 12–17 μm, R 5 16–22 μm.

Ventral idiosoma ( Fig. 36A View FIGURE 36 ). Presternal plates weakly sclerotized, diagonally striated and completely fused with sternal shield. Sternal shield 185–215 μm long, 75–90 μm wide (at widest part of iv2), with fine reticulation on entire surface (rarely reticulation indistinct, not well visible), weak sclerotization in anteriormost part with st1 and four pairs of setae placed very close to lateral margins; sternal setae st5 on soft integument adjacent to posterior margin of shield ( Fig. 36A View FIGURE 36 ). Seven pairs of opisthogastric setae (Jv1–Jv3, Jv5, Zv1–Zv3), all placed on soft integument. Anal shield 75–102 μm long, 100–125 μm wide, as in Figs 32B and 32C View FIGURE 32 , rounded anteriorly and laterally, strongly convex posteriorly, reticulate on medial preanal surface, densely and distinctly punctate on lateral and postanal surfaces; cribrum with a slightly curved row of denticles posterior to postanal seta.All scutal structures with fine micropunctation. Two pairs of metapodal platelets, slit-shaped inner platelets minute, barely observable, outer platelets distinct, suboval, subglobose or irregularly shaped. Peritreme long, with only a few narrow fragments of peritrematal shield in anterior and submedial parts; anterior tip free of podonotal shield and extending between setae z1 and s1. Lengths of selected ventrally located setae as follows: st1 18–25 μm, st2–st5 11–17 μm, ad 24–32 μm, pa 20–27 μm, Jv5 26–34 μm, Zv1 10–15 μm, and other opisthogastric setae 13–21 μm.

Gnathosoma ( Figs 32F View FIGURE 32 , 33C View FIGURE 33 , 36F, 36G View FIGURE 36 ). Ventral gnathosoma as in female ( Figs 32F View FIGURE 32 ), with following length of rostral setae: h1 26–33 μm, h2 10–15 μm, h3 36–43 μm, pc 19–26 μm. Middle article of chelicerae 101–111 μm long; movable digit 40–48 μm, usually with six teeth, but often also with five and rarely seven teeth; fixed digit with similar dentition as in female ( Fig. 33C View FIGURE 33 ). Anterior margin of epistome as in adults and Figs 36F and 36G View FIGURE 36 .

Legs ( Fig. 28C View FIGURE 28 ). All legs shorter than idiosoma: legs I 320–360 μm, legs II 255–300 μm, legs III 230–270 μm and legs IV 295–340 μm long. Setation as in adults, but some dorsal setae not as strong, and apicoventral setae (av1 and pv1) of tarsi II–IV thin, needle-like and with subapical arrangement. Other features as in female.

Material examined

Thirty-five females, 18 males, 38 deutonymphs— Slovakia, Borská Nížina Lowland, Tomky Village , Lásek Forest , pine forest with birch admixture, in fruiting body of old Fomes fomentarius growing on a trunk of Betula sp. , elevation 190 m, September 1, 2023; one deutonymph— Šaštín-Stráže Town, Gazárka Jubilejný Forest , mixed forest, on Fomitopsis betulina and a trunk of Betula sp. , elevation 175 m, June 25, 2024; three females, four males, seven deutonymphs (November 15, 2023), three females, one male, six deutonymphs (July 4, 2024)— Javorníky Mountains, Papradno Village , Papradnianka Brook Valley , mixed forest, on Ganoderma applanatum ( Basidiomycota : Polyporales ) on a spruce stump, elevation 450 m, July 4, 2024; one deutonymph— Little Carpathians Mountains, Bratislava Capital , Kamzík Forest , deciduous forest, on Bolitophagus interruptus Illiger ( Coleoptera , Tenebrionidae ) in old F. fomentarius on a trunk of Fagus sylvatica , elevation 340 m, May 6, 2019; 17 females, 9 males, 15 deutonymphs— Lozorno Village, Lintavy Forest , deciduous forest, in old F. fomentarius abundantly infested by Bolitophagus reticulatus (Linnaeus) ( Coleoptera , Tenebrionidae ) and Neomida haemorrhoidalis , on a trunk of Aesculus hippocastanum , elevation 340 m, September 10, 2023; seven females, eight males, six deutonymphs (including three deutonymphs on B. reticulatus )— Stupava Town, Riedky Vŕšok Mt. , deciduous forest, in F. fomentarius on a trunk of F. sylvatica , elevation 265 m, June 17, 2024; one deutonymph— Podunajská Rovina Flatland, Svätý Jur Town , Panónsky Háj Forest , deciduous forest, on Eledonoprius armatus ( Coleoptera , Tenebrionidae ) in Inonotus obliquus (Basidiomycota: Polyporales ) on a stem of Carpinus betulus , elevation 135, September 27, 2023; one deutonymph— Považský Inovec Mountains, Hrádok Village , Hrádocká dolina Valley , deciduous forest, on B. reticulatus found in F. fomentarius on F. sylvatica , elevation 350 m, June 1, 1995; three males, one deutonymph— Rimavská Kotlina Basin, Teplý Vrch Village , Hikóriový Porast Forest , oak forest with admixture of C. betulus , on Trametes gibbosa (Basidiomycota: Polyporales ) and stump of Quercus sp. , elevation 225 m, June 21, 2005; four females, two males, four deutonymphs— Slovenský Raj Mountains, Hrabušice Village , Suchá Belá Valley , spruce forest, in Ischnoderma benzoinum (Basidiomycota: Polyporales ) on a stump of Picea abies , elevation 580 m, October 1, 2024; six females, one male, 56 deutonymphs (including seven deutonymphs on B. reticulatus )— Tríbeč Mountains, Skýcov Village , Prostredný Vrch Mt. , deciduous forest, in F. fomentarius on a trunk of F. sylvatica , elevation 480 m, June 6, 2024 .

Ecological notes

Insectolaelaps latopini is one of the most common mesostigmatans on perennial xylotrophic fungi in Slovakia, as it colonises a broader spectrum of such polypores than other mycetobiont species (found on/in Fomes fomentarius , Fomitopsis betulina , Ganoderma applanatum , Inonotus obliquus , Ischnoderma benzoinum , Trametes gibbosa ) and at the same time is able to colonize the fruiting bodies already at the stage of their growth or incipient decomposition. It prefers particularly large fruiting bodies of the tinder fungus Fomes fomentarius , which are probably obtained by phoresy of deutonymphs on the black tinder fungus beetle, Bolitophagus reticulatus , which seems to be monophagous on tinder fungus, but other host fungi are also occasionally reported for this beetle ( Nilsson 1997). Remarkably, we have never found phoretically active deutonymphs of I. latopini on the beetle Neomida haemorrhoidalis , which could serve as a potential secondary host and which often occurs together with B. reticulatus in the same fruiting bodies of tinder fungus and is the phoretic host of the mite Bulbolaelaps neomidae . The different phoretic appetence of the two mites mentioned must also be pointed out, as findings of phoretic deutonymphs of the mite I. latopini on the host beetles are incomparably rarer compared to B. neomidae . This is probably due to the different bionomy, feeding requirements and reproductive and dispersal strategies.

The adult mites can easily be collected directly from the fruiting bodies of the tinder fungus with a moistened toothpick, especially from the spore-bearing lower layer when they move or hide in crevices or various surface irregularities. In older and already partially decomposed sporocarps, which have a high content of fungal remains, the adult mites can be collected abundantly inside the fungi. If the sporocarps are infested, the mites often like to hide in the silk-woven frass of the moth larvae from the Tineidae family near the entry holes that these larvae make on the underside of the fruiting body. These holes and the exit holes on the upper side of the fruiting body probably facilitate the penetration of various fungus-feeding beetles, including mites, into the interior of the fungus. The tubes of the hymenophores are narrow enough to be inhabited by these mites, as is the case with other fungi and other fungus-inhabiting and similarly sized mesostigmatic mites ( Lindquist 1995).

In contrast to the two previous digamasellid species, Insectolaelaps latopini is not monoxenous, i.e. strictly bound to a single phoretic host. Its dispersal can be ensured by phoresy on various darkling beetles, most frequently on the beetles Bolitophagus reticulatus , more rarely also on the related Bolitophagus interruptus and Eledonoprius armatus . Also in contrast to the two previous digamasellids, I. latopini occurred on fungi on which its phoretic hosts could not be detected. This could be related to the presence of other potential phoretic hosts used to spread the mites, such as fungivorous fruit flies of the family Drosophilidae or fungus gnats of the dipteran family Keroplatidae . For example, flies of the genus Drosophila Fallén are known to be hosts of mycetobiont mites of the genus Hoploseius Berlese ( Chant 1963) .

Taxonomic notes

Insectolaelaps latopini was originally described in 1982 by Hirschmann & Wiśniewski on the basis of illustrations of two females from the Caucasus (coastal area of the Black Sea), which were incorrectly identified as Insectolaelaps pini (Hirschmann) by Shcherbak (1980). Later, Wiśniewski (1984) redescribed the adults and deutonymph of this species under the name Dendrolaelaps (Insectolaelaps) latopini , which he found in a fungus Fomes fomentarius growing on a birch tree in Babki Forestry near Poznan ( Poland). He described and illustrated all the important morphological features of the species, with the exception of the metric data and chaetotaxy of the legs. I was able to examine a small part of the specimens from Babki redescribed by Wiśniewski and deposited in his collection in Poznan (one female and one deutonymph), and I can confirm a perfect match between the individuals from Poland and those collected by me in Slovakia.

When redescribing the species Insectolaelaps latopini, Wiśniewski (1984) was aware of the considerable mutual similarity with the related species Insectolaelaps pini and therefore attached great importance to their comparison in order to facilitate the differentiation of the two species. Despite his efforts, I. latopini could be misidentified and confused with I. pini in some analyzes of mites collected from wood-decaying fungi in Europe ( Salmane 2005; Gdula et al. 2024). As my preliminary study of a limited number of Insectolaelaps species collected in Slovakia has shown, the adult and deutonymphal stages of I. latopini can be easily and reliably distinguished from other congeneric species based on the chaetotaxy of the genu and tibia of legs III. These leg segments have eight setae in the representatives of the genus Insectolaelaps , two of which are anterolateral setae (al1, al2), whereas I. latopini has only one such seta (al2 missing) out of a total of seven setae. The absence of the anterolateral seta al 2 in both segments is unusual and has not been found in the other genera of the family, except for some neotenic forms in the genus Longoseius Chant ( Lindquist 1975) .