Ceratitis capitata (Diptera: Tephritidae) in Lebanon : evaluation of distribution and pupae microbiota

Abstract

Ceratitis capitata or the Mediterranean fruit fly (medfly) is a highly invasive and destructive pest due to its tolerance of various climatic and environmental conditions as well as broad host range, including hundreds of fruits and vegetables. Medfly has a great economic impact on fruit production, national market and world trade. The population in Lebanon has been on the rise since 2007 due to several factors including optimal climate and host conditions, insecticide resistance, and negligent regulatory and detection measures during fruit harvest and transportation. Medfly infestation in Lebanon has been costly on the agricultural sector; one of the country’s main source of income, from yield loss and control costs to environmental and export trade risks. Therefore, the objectives of this study were to elucidate the distribution and phenology of medfly within Lebanon and the host and climate factors that influence its abundance and distribution. Population dynamics were assessed to evaluate differences in regional adaptations. Lastly, the microbiota produced during the pupa stage was evaluated for potential protective and antimicrobial advantages that allow the pupa to survive in the soil. The seasonal phenology, abundance, and distribution of medfly in Lebanon were carried out through different monitoring and survey durations using traps baited with Trimedlure, while weather data including minimum and maximum temperatures, relative humidity, and precipitation rate were collected from the Lebanese Agricultural Research Institute. Results showed that the medfly is widespread in Lebanon and appears to be well adapted to all the microclimates found across different cazas and districts, and that it has established in specific niches with optimal weather factors and host fruit types. Temperature and host availability positively correlate with medfly abundance, while precipitation suppresses it. The phenology of medfly in Lebanon shows a yearly pattern of two peaks in June and September. Two parasitoid wasp species were identified emerging from the pupae. Local population differences were evident based on emergence rate, puparium color, and microbiota profiles. The culture-based results confirmed the presence of Enterobacteriaceae species produced by the pupae, in addition to fungal species. Moreover, for the first time in Lebanon, our results indicated a potential protective and antimicrobial role of the pupae microbiota that promotes survival against bacterial or microbial infections. The conclusions drawn from this study can ultimately contribute to the development of timely and sustainable customized control and management strategies with proper preventive and regulatory measures and with further research pave the way for strategies that target the pupa microbiota as a control measure.