Ribosomal ITS1 polymorphisms in Ceratitis capitata and Ceratitis rosa (Diptera : Tephritidae)

Ribosomal ITS1 DNA sequences have been characterized in Ceratitis capitata (Weidemann), the Mediterranean fruit fly, and Ceratitis rosa (Karsch), the Natal fruit fly. In C. capitata the ITS1 region is 831 bp in size (on avera ge), Relatively little variation in the makeup of the ITS1 DNA sequences wa s detected in individuals sampled from numerous worldwide populations of C. capitata, In C. rosa, however, a substantial difference in the size of the ITS1 region was observed in individuals from a collection made in Kenya co mpared with individuals front South Africa. In the C. rosa flies from South Africa, this region was approximate to 930 bp in size, compared with a siz e of 717 bp in the C. rosa Kenya flies, This difference appears to be due p rimarily to a single insertion or deletion event. Using polymerase chain re action. these size polymorphisms are easily detectable and can be used for making species identification and/or population origin determinations using material from any stage of the life cycle. Despite these intra and intersp ecific differences, sequences from the ITS1 regions of both C. rosa collect ions and C. capitata can still be aligned. Quantification of the similarity of these sequences may help to resolve continuing questions over the statu s of species relationships in this genus.