Search

Seasonal dynamics and reproductive phenological parameters of four Carabus species (C. convexus, C. coriaceus, C. germarii and C. hortensis) common in Hungary were studied by pitfall trapping and dissection. Beetles were collected in an abandoned apple orchard and in the bordering oak forest near Budapest (Central Hungary), in 1988–1991.The sex ratio was male-dominated, but this was significant only for C. coriaceus.The catch of C. germarii adults showed relatively short activity period with unimodal curve, but activity was longer and bimodal for the other three species. Adults of C. germarii and C. hortensis reached sexual maturity in July, and C. coriaceus adults were matured by early August. We did not find newly hatched individuals of C. coriaceus or C. germarii.The reproductive period was approximately four weeks in C. hortensis, five weeks for C. coriaceus and six weeks for C. germarii. Reproduction lasted much longer, for about four months, in C. convexus. The mean number of ripe eggs per female were 4.2 in C. convexus, 5.4 in C. coriaceus, 6.6 in C. germarii, and 7.4 in C. hortensis. The maximum number found was about three times the average in all studied species. The reproductive allocation (ratio of egg complement mass/body mass) was lowest in C. germarii (0.133) and highest in C. hortensis (0.196), and did not depend on body size.There was minimal overlap of the activity and reproductive periods of the four species.

To compare carabid assemblages from transgenic Bt- and isogenic maize in Hungary, we used pitfall traps in an experiment (30x30 m plots, arranged alternately in 6 replications), during the growing season of maize during 2001—2003. We captured altogether 44,103 individuals of 58 species. The most common species in our sampling were Calatlzus ambiguus, Doliclzus halensis, Harpalus distinguendus, H rufipes, Poecilus sericeus and Treclius quadristriatus. The same species dominated both in the Bt- and in the isogenic maize plots. Under our test conditions (plot size and 3 years of sampling), no significant differences were found either in the structural characteristics (number of individuals, number of species and diversity), activity density or seasonal activity patterns ofthe dominant species.