Seasonal dynamics, age structure and reproduction of four Carabus species (Coleoptera: Carabidae) living in forested landscapes in Hungary

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

Country-specific effects of neonicotinoid pesticides on honey bees and wild bees

Neonicotinoid seed dressings have caused concern world-wide. We use large field experiments to assess the effects of neonicotinoid-treated crops on three bee species across three countries (Hungary, Germany, and the United Kingdom). Winter-sown oilseed rape was grown commercially with either seed coatings containing neonicotinoids (clothianidin or thiamethoxam) or no seed treatment (control). For honey bees, we found both negative (Hungary and United Kingdom) and positive (Germany) effects during crop flowering. In Hungary, negative effects on honey bees (associated with clothianidin) persisted over winter and resulted in smaller colonies in the following spring (24% declines). In wild bees (Bombus terrestris and Osmia bicornis), reproduction was negatively correlated with neonicotinoid residues. These findings point to neonicotinoids causing a reduced capacity of bee species to establish new populations in the year following exposure

Pollination networks along the sea-inland gradient reveal landscape patterns of keystone plant species

Linking the functional role of plants and pollinators in pollination networks to ecosystem functioning and resistance to perturbations can represent a valuable knowledge to implement sound conservation and monitoring programs. The aim of this study was to assess the resistance of pollination networks in coastal dune systems and to test whether pollination interactions have an explicit spatial configuration and whether this affect network resistance. To this aim, we placed six permanent 10 m-wide belt transects. Within each transect we placed five plots of 2 m x 2 m, in order to catch the different plant communities along the dune sequence. We monitored pollination interactions between plants and pollinators every 15 days during the overall flowering season. The resulting networks of pollination interactions showed a relatively low degree of resistance. However, they had a clear spatial configuration, with plant species differently contributing to the resistance of pollination networks occurring non-randomly from the seashore inland. Our results evidenced that beside contributing to the creation and maintenance of dune ridges, thereby protecting inland communities from environmental disturbance, plant species of drift line and shifting dune communities have also a crucial function in conferring resistance to coastal dune pollination networks

Factors affecting the structure of bee assemblages in extensively and intensively grazed grasslands in Hungary

Bees are the most important pollinators in Europe. We studied bee assemblages on 7 pairs of extensively and intensively grazed sites in three lowland grassland types in Hungary. No chemicals were applied on the grasslands. The bees were collected using sweep net surveys and 1 m wide transect surveys in 2003. We mapped land-use types (grasslands; arable fields; forests; built-up areas; marshy habitat and open water) based on aerial photographs within a 500 m radius of each study site. We captured 483 individuals of 124 Apoidea species in total. This shows very diverse and species rich bee assemblages in these semi-natural grassland areas. Both diversity and percentage of rare species were the highest on the Kiskunság alkali area. The dominance of honey bee ( Apis mellifera ) was very low at each site. Neither species richness nor abundances differed between extensively and intensively grazed sampling sites, among regions, and between edge and interior of sites. However, both species richness and abundance of bees correlated positively with species richness and cover of flowering plants, indicating the important role of food sources. From the landscape parameters wet areas were preferred by small species, while large species tended to avoid build-up areas

Effect of conservation management on bees and insect-pollinated grassland plant communities in three European countries

It is now widely accepted that agricultural intensification drives the decline of biodiversity and related ecosystem services like pollination. Conservation management, such as agri-environment schemes (AES), has been introduced to counteract these declines, but in Western European countries these tend to produce mixed biodiversity benefits. Not much is known about the effects of AES in Central and Eastern European countries. We evaluated the effect of reduced stocking rates (0.5 cow/ha vs. >1 cow/ha) on bees and insect-pollinated plants in semi-natural pastures in Hungary. We sampled bees using sweep net and transect surveys in the edge and interior of the fields three times in 2003. On the same transects, we also estimated the cover of all plant species. We found no management effect on species richness and abundance with respect to cover of bees and insect-pollinated plants, but grazing intensity resulted in differences in species composition of insect-pollinated plants. Furthermore, we compared our results with those of a similar study carried out in Switzerland, and the Netherlands, but with different management regimes. There were positive effects of management in Switzerland, but conservation effects were lacking in the Netherlands. Species richness of both bees and insect-pollinated plants was highest in Hungary, intermediate in Switzerland and lowest in the Netherlands. Across all countries, the richness of insect-pollinated plants was a good predictor of bee species richness. Grassland extensification schemes were effective for bees and insect-pollinated plants in the country with intermediate land-use intensity and biodiversity only (Switzerland). The absence of effects in the Netherlands may have been caused by the management being highly intensive on both field types. In Hungarian grasslands biodiversity levels were high regardless of management and both investigated stocking rates may be qualified as conservation management. Therefore, agricultural policy in Hungary should encourage the maintenance of a variety of traditional grazing practices for conserving this still highly diverse pollinator fauna