LES INSECTES POLLINISATEURS DE LA LUZERNE (MEDICAGO SATIVA L.) EN FRANCE

Abstract

This article reports most of the informations provided by a 9 years survey in different regions of France. Observations are concerned with abundance and activity of Apoidea including honeybees. The author also gives data on flight periods, wild bees spectrum variations and pollen loads con- tents. The honeybee (90 p. cent of the apoïds population) never collects pollen from lucerne flowers. Nec- tar collecting workers trip about 1 p. cent of the visited flowers. There is no relation between honeybee density and seed yield. The highest number of wild bees recorded is 2 500 females/ha. A 1 000 kg/ha seed yield can be ex-pected if such a bee visitation occurs. The main native pollinators are: Melitrurga clai,icuriiis, Andreno labialis, A. ovatula, A. flai,ipes, Melitta leporina, Halictus marchali. Eucera clypeata. E. longicornis. Bombus terreslris, B. agrorum. A microscopic analysis of more than a thousand pollen loads demonstrates that A tidretia !rofu/o, A. labialis, Melitta leporina, Melitturga clat!icornis, Eucera lotigicortiis and E. clypeata are mostly attracted by Papilionaceae flowers (Trifolium pralense, T. rcpens, etc.) Halictus marchali and Andrena Jlavipes by Compositae an Bombus terrestris by various plant families.