Differences in ant (Hymenoptera, Formicidae) species composition between weight fractions of Rovno amber

Arboreal specialists (including Ctenobethylus goepperti ) comprise 54% of all ant inclusions in Rovno amber pieces weighing up to 1.5 g and 43% of those in larger pieces. In the small-size amber fraction, syninclusions containing more than a single worker ant are represented exclusively by the arboreal Dolichoderus spp. and C. goepperti , while syninclusions in larger amber pieces often contain workers of Lasius spp., which are not associated with trees. Species of Lasius comprise 15% of ants in the smaller and 28% in the larger amber pieces. It seems that the smaller pieces of amber have formed on the thinner branches of the amberproducing trees and, consequently, contain a larger proportion of arboreal ant species. Comparison of composition of inclusions between different weight fractions of amber is a promising tool to study fossil faunas and environments.