Detection of Wolbachia in Natural Populations of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) Infesting Argan Fruits in Morocco.

Abstract

The argan tree (Argania spinosa L. Skeels), native to the sub-Saharan region of Morocco, is an endangered agroforestry species renowned for producing one of the world's most expensive and sought-after oils. However, this valuable resource is threatened by the Mediterranean fruit fly (Ceratitis capitata (Wied.)), an invasive pest worldwide. Like other dipteran insects, C. capitata has developed mutualistic interactions with prokaryotic endosymbionts, including Wolbachia, a facultative intracellular bacterium that could play a role in the biology of this pest. Between 2022 and 2024, a field survey was conducted in the argan forests of Agadir, southern Morocco, to detect Wolbachia in natural populations of C. capitata and investigate its potential impact on this pest. A total of eighteen wild type specimens were captured to investigate the endosymbionts of this insect pest. Detection of Wolbachia was carried out by PCR using a primer pair targeting a specific fragment within the cox gene. Amplicons of the expected size were sequenced in both directions, and one sequence was deposited in the GenBank under accession Number PQ285444. Phylogenetic analysis showed that the obtained sequence belongs to the monophyletic clade of the Wolbachia B supergroup, known to infect a variety of insect species. To the best of our knowledge, this is the first report of the bacterium being detected and characterized in natural populations of the Mediterranean fruit fly infesting argan fruits in the country. These findings open new perspectives for integrated biological control strategies, offering a sustainable alternative to chemical insecticides for managing this insect pest species in Morocco.