Gottlieb, Y., Department of Entomology, Agricultural Research Organization, Volcani Center, Bet-Dagan, Israel, Department of Entomology, Agricultural Research Organization, Volcani Center, PO Box 6, Bet-Dagan 50250, Israel
Ghanim, M., Department of Entomology, Agricultural Research Organization, Volcani Center, Bet-Dagan, Israel
Gueguen, G., UMR CNRS 5558, Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon 1, Villeurbanne, France
Kontsedalov, S., Department of Entomology, Agricultural Research Organization, Volcani Center, Bet-Dagan, Israel
Vavre, F., UMR CNRS 5558, Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon 1, Villeurbanne, France
Fleury, F., UMR CNRS 5558, Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon 1, Villeurbanne, France
Zchori-Fein, E., Department of Entomology, Agricultural Research Organization, Newe Ya'ar Research Center, Ramat Yishay, Israel

Symbiotic relationships with bacteria are common within the Arthropoda, with interactions that substantially influence the biology of both partners. The symbionts' spatial distribution is essential for understanding key aspects of this relationship, such as bacterial transmission, phenotype, and dynamics. In this study, fluorescence in situ hybridization was used to localize five secondary symbionts from various populations and biotypes of the sweet potato whitefly Bemisia tabaci: Hamiltonella, Arsenophonus, Cardinium, Wolbachia, and Rickettsia. All five symbionts were found to be located with the primary symbiont Portiera inside the bacteriocytes - cells specifically modified to house bacteria - but within these cells, they occupied various niches. The intrabacteriocyte distribution pattern of Rickettsia differed from what has been described previously. Cardinium and Wolbachia were found in other host tissues as well. Because all symbionts share the same cell, bacteriocytes in B. tabaci represent a unique intracellular ecosystem. This phenomenon may be a result of the direct enclosure of the bacteriocyte in the egg during oogenesis, providing a useful mechanism for efficient vertical transmission by "hitching a ride" with Portiera. On the other hand, cohabitation in the same cell provides ample opportunities for interactions among symbionts that can either facilitate (cooperation) or limit (warfare) symbiotic existence.