Comparative morphological and histological characterization of the midgut in Hyalomma marginatum and H. excavatum (Acari: Ixodidae)

Ticks are among the most important blood-feeding ectoparasites affecting both human and animal health. The midgut is a key organ in ticks, as it is directly involved in blood digestion and represents the primary interface for pathogen development within the vector. However, detailed comparative information on the midgut structure of closely related Hyalomma species is still limited. In the present study, the midgut morphology and histology of Hyalomma marginatum and Hyalomma excavatum collected from different regions of Türkiye were examined and compared. In both species, the midgut was surrounded by a thin muscular layer and lined with a pseudostratified epithelium consisting of digestive and stem cells. Although the general organisation of the midgut was similar, clear interspecific differences were observed. Digestive cells differed notably in the amount and distribution of cytoplasmic granules, and the associated Malpighian tubules showed variation in the number of composing cells between the two species.These structural differences suggest that H. marginatum and H. excavatum exhibit species-specific characteristics in their midguts. The results provide baseline morphological and histological data that may be useful for future studies on tick physiology and vector–pathogen interactions.