Abstract
The paper presets the results of the study on the life span, survival, body weight and fecundity of cockchafer (Melolontha spp.) adults feeding on the leaves of Betula pendula Roth., Quercus robur L., Q. rubra L., Acer platanoides L., Tilia cordata Mill. and Pinus silvestris L. inflorescences. The life span and body weight of adults, as well as female fertility were examined in the years 2015, 2016 and 2017. In 2015, the tested common cockchafer (Melolontha melolontha L.) adults and forest cockchafer (Melololntha hippocastani F.) adults were fed on B. pendula., Q. robur and P. silvestris. In 2016, forest cockchafer adults were fed on B. pendula, Q. robur, Q. rubra, T. cordata, and in 2017 – on B. pendula., Q. robur T. cordata and A. platanoides. Adults of both species feeding on Q. robur were treated as the control. Adult specimens observed under laboratory conditions were collected in the field, shortly after leaving their overwintering sites in the soil. Our results showed that feeding on the leaves of Q. robur and Q. rubra had the greatest positive effects on the life span, body weight and fecundity of the studied cockchafer adults. M. melolontha females reared on the leaves of B. pendula laid no eggs. The leaves of A. platanoides constituted an adequate food source for the development of M. hippocastani. P. silvestris inflorescences proved to be the right food only for M. melolontha females. M. hippocastani adults feeding on T. cordata and B. pendula were characterized by a short life, decreasing body weight in the first days of observation and low fertility.