Comparison between green lacewing assemblages (neuroptera: chrysopidae) in the lower valleys of the danube (Rumania) and the Loire (France)

Abstract

Quantitative surveys were carried out in two European fluvial lower valleys, in Rumania (Danube Plain) and in France (Val-de-Loire). Various sites were investigated by various collecting methods. Faunistic richness is higher in Val-de-Loire whilst the diversity indices (Shannon and Hurlbert) show that the Plain of the Danube exhibits a significantly greater level of biodiversity. Seventeen species appear jointly in samples of the two valleys. The Plain of the Danube harbours characteristic Eurosiberian elements: Chrysopa dasyptera and Chrysopa hungarica, Val-de-Loire shows Westmediteranean ones: Dichochrysa picteti, D. inornata and Chrysoperla mediterranea. Concerning actual numbers of individuals, the Plain of the Danube is dwelt equally by chrysopids glyco-palynophagous and aphidophagous as adults (50/ 50 %) contrarily to Val-de-Loire which is essentially by glyco-palynophagous species (98 %), overwintering as adults (89 %) or larvae (9 %).