Citation: El Yamlahi, Y.; Bel Mokhtar, N.; Maurady, A.; Britel, M.R.; Batargias, C.; Mutembei, D.E.; Nyingilili, H.S.; Malulu, D.J.; Malele, I.I.; Asimakis, E.; et al. Characterization of the Bacterial Profile from Natural and Laboratory Glossina Populations. Insects 2023, 14, 840. https://doi.org/10.3390/ insects14110840 Academic Editors: David S. Haymer and Teresa Vera Received: 7 August 2023 Revised: 5 October 2023 Accepted: 27 October 2023 Published: 29 October 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). insects Article Characterization of the Bacterial Profile from Natural and Laboratory Glossina Populations Youssef El Yamlahi 1,2,3 , Naima Bel Mokhtar 1,3 , Amal Maurady 1,2 , Mohammed R. Britel 1 , Costas Batargias 4 , Delphina E. Mutembei 5 , Hamisi S. Nyingilili 5 , Deusdedit J. Malulu 5 , Imna I. Malele 6 , Elias Asimakis 3 , Panagiota Stathopoulou 3 and George Tsiamis 3, * 1 Laboratory of Innovative Technologies, NationalSchool of Applied Sciences of Tangier, Abdelmalek Essaâdi University, Tétouan 93000, Morocco; elyamlahi.youssef@gmail.com (Y.E.Y.); naima.belmokhtar@upatras.gr (N.B.M.); amal.maurady.ma@gmail.com (A.M.); mbritel@uae.ac.ma (M.R.B.) 2 Faculty of Sciences and Technics of Tangier, Abdelmalek Essaâdi University, Tétouan 93000, Morocco 3 Laboratory of Systems Microbiology and Applied Genomics, Department of Sustainable Agriculture, University of Patras, 2 Seferi St, 30131 Agrinio, Greece; eliasasim@gmail.com (E.A.); panayotastathopoulou@gmail.com (P.S.) 4 Department of Biology, University of Patras, 26504 Patras, Greece; cbatargias@upatras.gr 5 Vector & Vector Borne Diseases, Tanzania Veterinary Laboratory Agency (TVLA), Tanga P.O. Box 1026, Tanzania; phinadel5@gmail.com (D.E.M.); mnyingilili@gmail.com (H.S.N.); maluluone@gmail.com (D.J.M.) 6 Directorate of Research and Technology Development, TVLA, Dar Es Salaam P.O. Box 9254, Tanzania; maleleimna@gmail.com * Correspondence: gtsiamis@upatras.gr; Tel.: +30-26-4107-4149 Simple Summary: Tsetse flies are large biting insects that inhabit much of tropical Africa and have a significant economic impact as the biological vectors of trypanosomes, which cause serious dis- eases to humans and livestock. A large array of bacteria, termed collectively symbionts, inhabit the internal organs of the flies’ body. These bacterial symbionts are involved in important aspects of the flies’ biology, including nutrition and reproduction. For instance, the main bacterial sym- biont Wigglesworthia provides nutritional supplements necessary for host fertility and development, while Wolbachia is known to affect the reproduction of flies by causing a series of abnormalities. Therefore, the symbionts of tsetse flies show promising signs for exploitation and can be used for the development of innovative tools for the control of the flies and the diseases they carry. In this work, we used next-generation sequencing to characterize in detail the bacterial communities of four tsetse fly species. Their bacterial communities differed significantly, depending on the origin and the developmental stage of the flies. Certain important bacteria, such as Wigglesworthia and Sodalis, were present in all species and exhibited a high number of interactions with the other members of the bacterial community. Finally, Wolbachia was mostly present in G. morsitans samples. Abstract: Tsetse flies (Glossina spp.; Diptera: Glossinidae) are viviparous flies that feed on blood and are found exclusively in sub-Saharan Africa. They are the only cyclic vectors of African trypanosomes, responsible for human African trypanosomiasis (HAT) and animal African trypanosomiasis (AAT). In this study, we employed high throughput sequencing of the 16S rRNA gene to unravel the diversity of symbiotic bacteria in five wild and three laboratory populations of tsetse species (Glossina pallidipes, G. morsitans, G. swynnertoni, and G. austeni). The aim was to assess the dynamics of bacterial diversity both within each laboratory and wild population in relation to the developmental stage, insect age, gender, and location. Our results indicated that the bacterial communities associated with the four studied Glossina species were significantly influenced by their region of origin, with wild samples being more diverse compared to the laboratory samples. We also observed that the larval microbiota was significantly different than the adults. Furthermore, the sex and the species did not significantly influence the formation of the bacterial profile of the laboratory colonies once these populations were kept under the same rearing conditions. In addition, Wigglesworthia, Acinetobacter, and Sodalis were the most abundant bacterial genera in all the samples, while Wolbachia was significantly abundant Insects 2023, 14, 840. https://doi.org/10.3390/insects14110840 https://www.mdpi.com/journal/insects