Variability of the Mandibular Sclerite and Its Value in Diagnostics of the Third Instar Larvae of the Mediterranean Fruit Fly Ceratitis capitata (Wiedemann, 1824) (Diptera, Tephritidae)

The Mediterranean fruit fly Ceratitis capitata (Wiedemann, 1824) is an important quarantine pest in the Eurasian Economic Union. The species is traditionally identified by morphological characters of the III instar larvae found in imported fruit products. In view of the existing discrepancies in the use of the mandibular sclerite characters in quarantine phytosanitary diagnostics of the III instar larvae of C. capitata, it is important to assess the intraspecific variability of this structure and to emend the identification keys accordingly. Analysis of microscopic preparations showed the morphometric parameters of mandibular sclerites to be highly variable in C. capitata. In particular, no correlation of these parameters with the geographic origin or host plants of the larvae was demonstrated in our material. Variability within the regional groups of samples exceeded the differences between the regions. Thus, data on the qualitative and quantitative variation of the mandibular sclerite in the III instar larvae, combined with the information on the invasive activity and the broad trophic spectrum in the Mediterranean fruit fly, indicate a wide reaction norm in this species.