ENZYMATIC POLYMORPHISM IN NATURAL-POPULATIONS OF THE SAWFLY DIPRION-PINI L (HYMENOPTERA, DIPRIONIDAE)

Diprion pini L is a sawfly whose larvae cause sudden, brief and specta cular defoliation on Pinus sylvestris. In France, bivoltine population s in lowland areas and univoltine populations in mountain areas cohabi t, all living in forests located at varying distances from each other. The characteristics of the diapause of mountain populations are diffe rent from those of lowland populations. Six natural populations were s tudied using enzymatic electrophoresis to identify markers reflecting genetic heterogeneity in the French D pini populations: three lowland (Rambouillet, Romorantin, Lorris) and three mountain populations (Sain t-Just-Saint-Rambert, Ceillac, Fontchristianne). The study of enzymati c polymorphism concentrated on six loci: three polymorphic esterase lo ci, a monomorphic malate dehydrogenase locus, a monomorphic and a poly morphic amino-peptidase loci. The determination of genetic distance be tween populations did not allow us to discriminate between bivoltine l owland populations and univoltine mountain populations. The population s fell into two sub-groups: those from the Alps and Rambouillet, and t hose from central France (Lorris, Romorantin and Saint-Just-Saint-Ramb ert).