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.