Lysiphlebus testaceipes (Cresson), an exotic aphid parasitoid established in the Mediterranean coast, has been regularly found in Lleida, and in the Pyrenees parasitising several aphid species. This shows the expansion of the parasitoid from coastal areas to the inland and mountain areas. The aphid species Aphis ruborum Borner, specific of Rubus sp., the polyphagous Aphis fabae Scopoli, Brachycaudus cardui L., and Aphis urticata J.F. Gmelin, specific of Urtica sp., were usual host of L. testaceipes in the studied areas. The presence of transzonal biocorridors, joint to the oligophagous host range of L. testaceipes and its capacity to alternate between available host aphid species has contributed to the successful expansion of the parasitoid from the coast to the inland or mountain areas. Lysiphlebus testaceipes (Aphidiidae) : Parasite Aphidoidea (Sternorrhyncha) : Host Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Land zones; Palaearctic region; Eurasia; Europe Aphidoidea; Hymenopteran parasites; Host range; implications for parasite distribution expansion; Lysiphlebus testaceipes; Spain; North east Lysiphlebus testaceipes; Hemipteran hosts; Host range; implications for distribution expansion; Aphidoidea; Spain; North east none