taxonID	type	description	language	source
620687BC801CFFCD6EDB5EB9FBA6FD16.taxon	description	the developing stylostomes easily penetrate the epidermis opening by their distal ends to the connective tissue layer of dermis (Figures 3, B-C, 4, A, C). The developed stylostomes lie at different angles to the epidermal surface, which makes it impossible to observe the entire stylostome, even in sections perpendicular to the surface of the epidermis (Figures 3, A-C, 4, A-C). In any case, an eosinophilic zone with dark-red coloration, into which the cheliceral movable digits are immersed, represents the proximal and initial portion of the stylostome (Figure 3, B-C). This stylostome portion apparently corresponds to the eosinophilic cone – the proximal part of any stylostome studied so far (e. g. Shatrov 2009). Typically, the lateral sides of the eosinophilic cone penetrate under the upper squamae of the stratum corneum. Below the eosinophilic cone, the stylostome slightly widens and loses coloration (Figures 3, B-C, 4, A, C). In its distal portion, the stylostome become again narrower and acquires a dark-blue staining (Figures 3, B, 4, A-B). The stylostome canal is regularly round in near-transverse sections, may. Note that the stylostome of the still-attached, nearly fully-fed larva shows only its proximal portion restricted within the epidermis. Scale bar ⚶ 50 µm ; C ⚶ Nearly transverse section of a developed stylostome at the level of its middle portion and a possibly young stylostome with moderately developed eosinophilic cone, into which the cheliceral movable digits are cemented. Note the empty axial canal of the developed stylostome. Scale bar ⚶ 50 µm. cap ⚶ capillary ; car ⚶ ear cartilage ; chb ⚶ cheliceral blades ; der ⚶ dermis ; ec ⚶ eosinophil cone ; ep ⚶ epidermis ; hl ⚶ horn layer ; lar ⚶ larva ; mp ⚶ mouthparts of larva ; st ⚶ stylostome ; stc ⚶ stylostome canal. a contain cell debris of the host and opens freely into the subjacent host tissues (Figures 3, B-C, 4, A-B). Erythrocytes were not observed in the stylostome canal. Externally, a thin layer of necrotic host cells surrounds the stylostome (Figures 3, C, 4, A, C). Examination of sections using differential-interference contrast (DIC) shows that the hyaline-like substance of the stylostome exhibits a gel-like consistency due to crumpled traces of sections (Figure 4, C). In response to the parasite feeding, the host develops a moderate inflammatory reaction with edema of the connective tissue layer, where neutrophil leucocytes, macrophages and mast cells are present (Figure 4, D). Other lymphocyte types are poorly distinguished. The peripheral blood vessels are dilated (Figure 4, D). Beneath the developed stylostome, a particular tissue sinus may be observed, in which the connective tissue fibers are mostly dissolved and a certain number of destroyed and intact infiltrating cells may be present (Figure 4, A-C). However, this tissue sinus is much lesser expressed than in infestations with many other trombiculid larvae (e. g. Shatrov 2009).	en	ShatrovK, Andrey B., Kazakov K, Denis V., Antonovskaia K, Anastasia A. (2025): Stylostome of Leptotrombidium myotis larvae (Ewing, 1929) (Acariformes, Trombiculidae) feeding on two different bat species (Vespertilionidae). Acarologia 65 (1): 173-196, DOI: 10.24349/o879-3rst, URL: https://doi.org/10.24349/o879-3rst
620687BC8011FFC86EDB59D0FDCCFEAA.taxon	description	3 - 5 or more cell layers. Parasitism of larvae on this host species, however, causes a strong inflammatory reaction with abundant cellular and fluid exudate and complete destruction of the epidermis. Erythrocytes leaving the dilated peripheral blood vessels and the infiltrate cells – leukocytes and lymphocytes – fuse together into the various necrotic masses, which cover the skin (Figure 5, A-B) displacing the epidermis. Larvae at the final feeding stages tightly immerse into these masses in several rows (Figure 5, B). As a result, the larvae, in order to reach the dermis, secrete a stylostome, which is slightly longer, up to 200 µm, than that evolving during feeding on P. ognevi inside the ear (Figure 6, A-B). Nevertheless, there are no significant differences in the stylostome organization between these two host species. The dark-red eosinophilic cone, poorly expressed, represents the proximal portion of the stylostome (Figure 6, A). A white to pale-pink substance forms the widest and largest portion of the stylostome (Figures 5, A, 6, A-B). The distal, narrower portion of the stylostome is dark-blue (Figure 6, A-B, D). The axial stylostome canal is confined by a narrow rim, which is either completely uncolored or shows a reddish or bluish staining (Figures 5, A, 6, B, D). The axial canal is around 10 µm in diameter, similarly to the case of P. ognevi, it opens freely into the subjacent tissues (Figure 6, C-D) and may contain various cellular debris (Figure 6, B). As in the case of P. ognevi, the stylostomes penetrate into the skin at different angles that makes it impossible to observe the entire stylostome at once. Nevertheless, it may be assumed that the total length of the stylostome may reach 200 µm or more, whereas its maximum width is around 50 - 70 µm. The outer borders of the stylostome are quite distinct and do not show an apparent transitional zone between the stylostome substance and the surrounding necrotic cell masses (Figure 6, A-B). Sometimes, however, a pink rim of a supposedly denser substance may be observed at the stylostome periphery (Figure 6, C-D). The evident tissue sinus underneath the stylostome is not observed due to a strong cellular infiltration of the inflammation area (see below). Feeding of L. myotis larvae on the bat M. davidii induces a strong inflammation with predominance of neutrophil leucocytes and mononuclear lymphocytes (macrophages) in the focus of the lesion (Figure 7, A-C). The inflammatory response is additionally characterized by a dilation of the peripheral capillaries (Figure 7, A) and strong hemorrhages spreading over a large area in the dermal connective tissue (Figure 7, B-C). Upon the release of both the necrotic cell masses and the liquid exudate onto the skin surface, they transform into a hardened, scab-like, coagulated mass composed of either tightly packed necrotic cells (Figure 7, B) or only blood plasma (Figures 5, B, 6, A). In contrast with P. ognevi, skin inflammation of M. davidii does not show the presence of numerous mast cells in the inflammation focus an 50 µm ; B ⚶ Distal narrower portions of two stylostomes situated at different angles to each other. Scale bar ⚶ 50 µm ; C ⚶ Nearly perpendicular section of the stylostome in its middle portion surrounded by a thin layer of necrotic tissue. DIC. Scale ⚶ bar 50 µm ; D ⚶ Situation in the host dermis adjacent to the inflammatory focus indicating the presence of numerous must cells. Scale bar ⚶ 50 µm. cap ⚶ capillary ; car ⚶ ear cartilage ; der ⚶ dermis ; ep ⚶ epidermis ; hl ⚶ horn layer ; mc ⚶ mast cell ; mac ⚶ macrophage ; nc ⚶ necrotic cells ; nl ⚶ neutrophil leucocyte ; pl ⚶ papillary layer ; sin ⚶ tissue sinus ; st ⚶ stylostome ; stc ⚶ stylostome canal. ear of the bat Myotis davidii. AzurII-eosin-stained sections. A ⚶ Strong ulceration of the skin with total degradation of the epidermis in mass feeding of larvae. Note a scab-like substance on the skin surface composed of both destroyed inflammatory cells and erythrocytes. Scale ⚶ bar 100 µm ; B ⚶ Ulceration of the skin in mass feeding of larvae. Note enormous masses on the skin surface composed of either fused destroyed inflammatory cells forming a scab-like substance or blood plasma, in which larvae are immersed. Scale bar ⚶ 100 µm. bp ⚶ blood plasma ; car ⚶ ear cartilage ; der ⚶ dermis ; ep ⚶ epidermis ; hem ⚶ hemorrhage ; hl ⚶ horn layer ; nc ⚶ necrotic cells ; sc ⚶ scab-like substance ; sin ⚶ tissue sinus ; st ⚶ stylostome.. Scale bar ⚶ 50 µm. bp ⚶ blood plasma ; car ⚶ ear cartilage ; chb ⚶ cheliceral blade ; der ⚶ dermis ; ec ⚶ eosinophilic cone ; mp ⚶ larval mouthparts ; nc ⚶ necrotic cells ; st ⚶ stylostome ; stc ⚶ stylostome canal. the outer ear surface of the bat Myotis davidii. AzurII-eosin-stained sections. A ⚶ Dilated capillaries in the dermis surrounded by numerous inflammatory cells adjacent to the damaging focus. Scale bar ⚶ 50 µm ; B ⚶ A strong hemorrhage impregnated by leucocytes underneath the hyperplastic epidermis covered by a scab-like substance. Scale bar ⚶ 50 µm ; C ⚶ Different inflammatory cells with predominance of neutrophil leucocytes and the hemorrhage in the dermis adjacent to the damaging focus. Scale bar ⚶ 10 µm ; D ⚶ Numerous inflammatory cells in the affected area of dermis with single mast cells. Scale bar ⚶ 10 µm. cap ⚶ capillaries ; car ⚶ ear cartilage ; der ⚶ dermis ; ep ⚶ epidermis ; fb ⚶ fibroblast ; hem ⚶ hemorrhage ; ic ⚶ inflammatory cells ; lym ⚶ lymphocyte ; mac ⚶ macrophage ; mc ⚶ mast cell ; nl ⚶ neutrophil leucocytes ; sc ⚶ scab-like association of necrotic cells. (Figure 7, D). Eosinophil and basophil leukocytes were not observed with certainty in either host species.	en	ShatrovK, Andrey B., Kazakov K, Denis V., Antonovskaia K, Anastasia A. (2025): Stylostome of Leptotrombidium myotis larvae (Ewing, 1929) (Acariformes, Trombiculidae) feeding on two different bat species (Vespertilionidae). Acarologia 65 (1): 173-196, DOI: 10.24349/o879-3rst, URL: https://doi.org/10.24349/o879-3rst
