Dr. Steinmann Henrik szerk.: Folia Entomologica Hungarica 22/1-11. (Budapest, 1969)
III. Relation of the soil-type to the number of pollinators per hectare and the composition of the population According to the data in Table No. 5. the number of pollinator wild bees is the greatest on the plain-type, hard, clay soil, less on medium hard and still less on the sandy clay soil. To most of the lucerne pollinator species the hard soil is advantageous, therefore, in areas of sandy soil they occur in smaller number only.The wild bees fauna of the sandy areas is but slightly poorer than that of the hard soils but the animals of the sandy areas are not lucerne pollinators. The sandy soiled region between rivers Danube and Tisza, however, are in a special position. Here the soil is mixed to a lesser extent with quartz components, wherefore, the animals of the hard soils accur in a relatively greater number,and because in this region the wheather conditions are warmer Melitturga clavlcornis appears in masses. Table No. 5. The influence of the soil-type on the number of pollinators per hectare Number of pollinators per hectare in Type of soil County Pest County Szolnok County Haj du County Békés X n X n X n X n Hard , plain—type , clay, somewhat salting 2363 (32) 1712 (15) 1561 (6) Medium hard, plain-type clay 1431 (13) 2059 (4) 1470 (11) 1432 (14) Sandy clay 786 (6)
