The distribution and importance of Microsoma exigua Mg. (Dipt., Tachinidae), a parasitoid of adult Sitona spp. (Col., Curculionidae) in the Mediterranean region.

Surveys conducted in the Mediterranean parts of Europe, North Africa, and of the Middle East have revealed that M. exigua had, in fact, a much wider distribution range than previously recorded. Eight common species of the genus Sitona are reported here as hosts of the tachinid, which was by far the predominant natural enemy of adult weevils in the Provence (southern France, 61.2% of the entomophagous complex), and in Greece (54.9%). The importance of M. exigua was exceptionally high in southwest Anatolia (Asian Turkey, 94.6 % of the complex of natural enemies), where the fly apparently played a key role in the regulation of the population dynamics of Sitona spp., reaching a parasitization rate of 57.1 % on average for the period 1981–84.