Dr. Steinmann Henrik szerk.: Folia Entomologica Hungarica 22/1-11. (Budapest, 1969)

The influence of the soil-type on the proportion and number of bivoltine long flight pollinators per hectare Type of soil County Pest County Szolnok County Haj du County Békés * ind/ha * ind/ha * ind/ha ind/ha Hard, plain-type, clay, somewhat salting 44 1039 63 1078 28 437 Medium hard, plain-type clay 49 701 38 782 45 661 59 845 • Sandy clay 23 180 The short flight group does not show any considerable change relative to the type of soil (Table No. 6.). The long flight bivoltine pollinators show a decreasing proportion and number per hectare in relation to the reduction in hardness of the soil. Our data relating to county Békés seem to be an exception (Table No.8.). Although according to our orientative surveys made in the north-east part of Hungary and on the regions between rivers Danube and Tisza the proportion of this group, too, diminishes on sandy soils, yet they are more multitudious than the short flying Melitta leporina and Rhophitoides canus

. On medium hard soils mainly the Andrena species represent this group.The middle flying species show - to a certain extent - diminishing proportion and number per hectare relative to the reduction in the hardness of soil (Table No. 7.)- The data demonstrate well enough the density of middle flight pollinators, i.e.: they are more multitudious in counties Szolnok and Békés than in Best and Hajdu.