Microbial community variations in adult Hyalomma dromedarii ticks from single locations in Saudi Arabia and Tunisia

Myriam Kratou ¹ Apolline Maitre ^2,3 Lianet Abuin-Denis ² Rachid Selmi ¹ Hanène Belkahia ¹ Abdullah D Alanazi ⁴ Hattan Gattan ⁵ Bassam M Al-Ahmadi ⁶ Abdullah Shater ⁷ Lourdes Mateos-Hernández ² Dasiel Obregon ⁸ Lilia Messadi ¹ Alejandro Cabezas-Cruz ^2* Mourad Ben Said ^1*

• ¹ National Veterinary School of Sidi Thabet, Ariana, Tunisia
• ² Laboratoire de Santé Animale de Maisons-Alfort (ANSES), Maisons Alfort, France
• ³ Laboratoire de Recherches sur le Développement de l'Elevage (INRA), Corte, France
• ⁴ Department of Biology, College of Science and Humanities, Shaqra University, Ad-Dawadimi, Riyadh, Saudi Arabia
• ⁵ College of Applied Medical Sciences, King Abdulaziz University, Jeddah, Makkah, Saudi Arabia
• ⁶ College of Science, Taibah University, Yanbu, Saudi Arabia
• ⁷ Department of Medical Laboratory Technology, College of Applied Medical Sciences, University of Tabuk, Tabuk, Saudi Arabia
• ⁸ School of Environmental Design and Rural Development, Ontario Agricultural College, University of Guelph, Guelph, Ontario, Canada

The camel-infesting tick, Hyalomma dromedarii, is a prominent ectoparasite in the Middle East and North Africa (MENA) region, critically impacting camel health and acting as a vector for tick-borne pathogens. Despite prior studies on its microbiota, the effects of geographic origin and sex on microbial community structure and functional stability remain poorly understood.Therefore, in this study, we characterized the bacterial microbiota of Hyalomma dromedarii ticks from camels in Tunisia (TUN) and Saudi Arabia (SA) using 16S rRNA gene sequencing, microbial network analysis and metabolic pathway prediction. Our findings indicate a dominant presence of Francisella endosymbionts in Tunisian ticks, suggesting adaptive roles of Hy. dromedarii ticks in arid ecosystems. Keystone taxa, particularly Staphylococcus and Corynebacterium, were identified as central to microbial network structure and resilience.Moreover, network robustness analyses demonstrated enhanced ecological stability in the Tunisian tick microbiota under perturbation, indicative of higher resilience to environmental fluctuations compared to Saudi Arabian ticks. Additionally, functional pathway predictions further revealed geographically distinct metabolic profiles between both groups (Tunisia vs.Saudi Arabia and males vs. females), underscoring environmental and biological influences on Hy. dromedarii microbiota assembly. These results provide insights into region-specific and sex-specific microbial adaptations and potential implications for pathogen transmission dynamics and vector resilience.