Characterization of the microbial communities in Tunisian wild populations of the Mediterranean fruit fly (Ceratitis capitata) and their implications for the future implementation of the sterile insect technique.

Abstract

Insects and their associated microbiota have developed a sustained and mutually beneficial relationship, characterized by the influence of the symbiotic microorganisms on the host's physiological processes and fitness parameters. The Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae), is one of the world's most ubiquitous, invasive, and harmful agricultural pests. In Tunisia, the medfly is widely distributed across all bioclimatic zones. However, in the absence of surveillance, infestations can escalate drastically, causing damage levels as high as 100%. Our study aimed to characterize the microbiome profile of Tunisian medfly populations from Zaghouan, Tozeur, Siliana, and Bizerte to understand the microbial dynamics implicated in the invasiveness and adaptability potential if SIT is applied. We conducted amplicon sequencing using MiSeq Illumina and a culture-dependent approach. Our findings revealed notable differences in symbiotic communities across regions. For instance, Serratia was prevalent in Tozeur populations, while Klebsiella showed high abundance in Bizerte. The composition of the bacterial communities within the medfly populations was influenced by several factors including the environmental conditions, geographical location, developmental stage, and the sex of the insects. Investigating the intricate relationship between insects and their microbiota is pivotal for understanding their biology and developing effective pest management strategies. Additionally, the isolation of bacteria from adult and larval medflies collected in the Bizerte region revealed the presence of bacterial species that could be utilized as attractants or supplements in larval artificial diets in the case of application of the SIT aiming at producing competitive sterile males.