Gábor Bakonyi

Long-term effects of heavy metals and microelements on nematode assemblage.

Effects of Cd, Cr, Se and Zn at a maximum rate of 270 mg kg(-1) were studied on a nematode assemblage after 6-10 years of application. Winter wheat, sunflower, sorrel, barley and rape were grown on the experimental field. Cd had a moderate effect on nematodes in spite of the fact that this element significantly decreased plant biomass. Cr was harmful to plants only in the first year of the study. However, Cr decreased Aporcelaimellus density and maturity index, increased Pratylenchus density and bacterial-fungal ratio, changed the c-p structure and feeding type composition. Se proved to be very toxic at a concentration of 11 mg kg(-1) (NH(4)-acetate+EDTA soluble form). Some advantageous effects of Zn were found in the first year. These disappeared later on. Remarkable between-year fluctuations of the nematode assemblage composition were observed.

Spatial pattern of water bugs (Nepomorpha, Gerromorpha) at different scales in the Szigetköz (Hungary)

In 2003, 26 Heteroptera species (16 aquatic and 10 semiaquatic) were collected from 53 sampling sites in the Szigetköz region in Hungary. Hyocoris cimicoides and Gerris argentatus were the most frequent aquatic and semiaquatic species, respectively. Large differences both in the species number and species composition were observed among the different flood-prevention areas, arm systems and habitats. Strong negative correlation was found between the average number of aquatic species and current velocity, and a strong positive correlation between the average number of aquatic and semiaquatic species and macrophyte density. From a faunistic point of view, the marsh at Arak is the most interesting and valuable site.

Effects of Consumption of Bt-maize (MON 810) on the Collembolan Folsomia candida, Over Multiple Generations: A Laboratory Study

The effect of long-term feeding on Bt-maize by collembolans in the laboratory is virtually unestablished. That is why the aim of the present study was to test whether the reproduction, fecal pellet production or food preference of the collembolan F. candida is affected when fed on Bt-maize for several consecutive generations. The collembolans were fed with Bt-maize for 0, 6, 16 and 22 months and the number of eggs and fecal pellets were determined. The experiment was repeated seven months later with the same populations. Food preference tests were additionally performed. Significant differences were found in food consumption, egg production and food preference between populations in some cases, but no time-response effect was observed. In conclusion, several generations feeding of F. candida on Cry1Ab toxin containing Bt-maize seems not to be harmful to this collembolan species.

Revised and annotated checklist of aquatic and semi-aquatic Heteroptera of Hungary with comments on biodiversity patterns

Abstract A basic knowledge of regional faunas is necessary to follow the changes in macroinvertebrate communities caused by environmental influences and climatic trends in the future. We collected all the available data on water bugs in Hungary using an inventory method, a UTM grid based database was built, and Jackknife richness estimates and species accumulation curves were calculated. Fauna compositions were compared among Central-European states. As a result, an updated and annotated checklist for Hungary is provided, containing 58 species in 21 genera and 12 families. A total 66.8% of the total UTM 10 × 10 km squares in Hungary possess faunistic data for water bugs. The species number in grid cells numbered from 0 to 42, and their diversity patterns showed heterogeneity. The estimated species number of 58 is equal to the actual number of species known from the country. The asymptotic shape of the accumulative species curve predicts that additional sampling efforts will not increase the number of species currently known from Hungary. These results suggest that the number of species in the country was estimated correctly and that the species accumulation curve levels off at an asymptotic value. Thus a considerable increase in species richness is not expected in the future. Even with the species composition changing the chance of species turn-over does exist. Overall, 36.7% of the European water bug species were found in Hungary. The differences in faunal composition between Hungary and its surrounding countries were caused by the rare or unique species, whereas 33 species are common in the faunas of the eight countries. Species richness does show a correlation with latitude, and similar species compositions were observed in the countries along the same latitude. The species list and the UTM-based database are now up-to-date for Hungary, and it will provide a basis for future studies of distributional and biodiversity patterns, biogeography, relative abundance and frequency of occurrences important in community ecology, or the determination of conservation status.

New Method for Automatic Body Length Measurement of the Collembolan, Folsomia candida Willem 1902 (Insecta: Collembola)

The collembolan, Folsomia candida, is widely used in soil ecotoxicology. In recent years, growth rate of collembolans has become as frequently used endpoint as reproduction rate in ecotoxicological studies. However, measuring collembolan body sizes to estimate growth rate is a complicated and time-consuming task. Here we present a new image analysis method, which facilitates and accelerates the body length measurement of the collembolan Folsomia candida. The new software package, called CollScope, consists of three elements: 1) an imaging device; 2) photographing software; 3) an ImageJ macro for image processing, measurement and data analysis. We give a complete description of the operation of the software, the image analyzing process and describe its accuracy and reliability. The software with a detailed usage manual is attached as Supplementary Material. We report a case study to demonstrate that the automated measurement of collembolan body sizes is highly correlated with the traditional manual measurements (estimated measuring accuracy 0.05 mm). Furthermore, we performed a dose-response ecotoxicity test using cadmium-sulfate by using CollScope as well as classical methods for size measurement. Size data measured by CollScope or manually did not differ significantly. Furthermore the new software package decreased time consumption of the measurements to 42% when tested on 35 animals. Consequently, methodological investigations performed in this study should be regarded as a recommendation for any other routine dose-response study where body growth is an endpoint.

Philopatry analysis of the great reed warbler (Acrocephalus arundinaceus) based on ringing data in Europe

Ringing databases of the EURING Data Bank and the Hungarian Bird Ringing Centre were analysed in order to investigate the philopatry of the great reed warbler (Acrocephalus arundinaceus) in three European regions. The aim of the study was to find out if there are continent-scale geographic trends in philopatry with respect to the age of the birds. Three clusters were assigned according to their geographic positions: (i) southern part of Europe (Region 1: between 36°–43° latitudes), (ii) middle part of Europe (Region 2: between 43°–49° latitudes) and (iii) northern part of Europe, (Region 3: between 49°–56° latitudes). No significant differences were found between the natal and breeding philopatry in any Regions, except Region 3. The birds ringed as adults in Region 3 were less faithful to their breeding site than those of the other two regions. Natal philopatry of juveniles did not differ between Region 1 and Region 2, but both of them differed in this respect from Region 3. A method for choosing appropriate breeding periods in philopatry studies is also proposed.

Seven decades of monitoring the aquatic bug fauna of Lake Balaton (Heteroptera: Nepomorpha)

Detailed faunistic data originating from four sampling series of aquatic Heteroptera (Nepomorpha) in the Lake Balaton (the largest shallow lake of Central Europe) between 1928 and 2002 were analysed. A comparative analysis confirmed that the aquatic bug fauna of this great lake can be established with suitable accuracy if it is sampled by different but devoted collectors. So far 26 species of aquatic bugs have been reported from here. The fauna changed considerably during the seven decades. Species lists of the four basins of the lake established during the four sampling periods show characteristic differences. Not only the frequency of four Micronecta species (Micronecta griseola, M. pusilla, M. scholzi, M. minutissima) changed characteristically but there has been a distinct change in the ratio of rare species too. Rare species were present in significantly higher proportion in the period 1928–1930 than in any of the later samplings between 1984 and 2002. All these changes run parallel with the direction of anthropogenic influences.

Multigenerational and Transgenerational Side-Effects of an Insecticide on Eggs of Folsomia candida (Collembola)

ABSTRACT Environmental toxicants such as insecticides are able to provoke epigenetic alterations which can be inherited to future generations. The aim of the current study was to assess whether the insecticide Trebon 10F (containing the active ingredient etofenprox) causes multigenerational and/or transgenerational effects on the egg traits of the collembolan Folsomia candida. The parent generation was kept in soil treated with three concentrations of the insecticide. The hatched offspring from each treatment were divided into two groups and were treated in the same manner as their parents (multigenerational effect), or remained untreated (transgenerational effect). The parents reacted with smaller eggs to the insecticide in a concentration dependent manner. Both multigenerational and transgenerational effects were detected in the offspring generations. While neither the number of eggs nor the ratios of the egg diameters (shortest/longest diameter) changed, the egg size increased as the Trebon 10F concentration increased. This is an indication that parents living under insecticide stress transmit this information to their offspring, who react with higher quality egg production. Such alterations in egg traits may have important consequences on the F. candida population dynamic.

Habitat use and movement activity of two common predatory water bug species, Nepa cinerea L., 1758 and Ilyocoris cimicoides (L., 1758) (Hemiptera: Nepomorpha): field and laboratory observations

Predatory invertebrates play a significant role in the organisation of aquatic communities. However, their ecology is poorly known even for many common taxa. We examined the meso-habitat use and aspects of movement activity of two common predatory water bug species Ilyocoris cimicoides (L., 1758) and Nepa cinerea L., 1758 under field and laboratory conditions in order to assess the effect of the patchiness on habitat choice. Ilyocoris cimicoides preferred open habitats, rich in submerged vegetation, without submerged terrestrial materials. Shaded habitats such as under trees, with moderately dense vegetation and submerged branches, were favoured by N. cinerea. Both laboratory and field data indicated differences in the short-term and similarity in the long-term movement behaviour of the two species. In the short-term, I. cimicoides moved frequently, while N. cinerea moved rarely, but the distance visited over the course of a longer time span is comparable.

Effects of genetic modification on the decomposition of corn residues measured by litter-bag method

Our objectives were to assess and rank 3 soil condition variants - root zone improving (RI), mulch leaving (NIL) and minimum disturbing (MD) - suitability to soil quality improvement and demonstrate the plant responses to different soil state and rind a possible relation between soil condition and plant growth under extreme climate. To rank the soil-plant interrelations twelve soil and plant factors were assessed; quality and depth of loosening state, surface protection by plants and stubble residues, soil aggregation, earthworm number, water supply in the root zone, tillage-induced C-flux, rooting depth of plants, yield, dry biomass and biomass recycling. Finally, seven fundamental requirements were selected to mitigate climate-stress and to improve plant resistance to the heat damage. A climate damage mitigation soil tillage strategy can establish a harmony between soil conservation and the demands of crop production.The results of a small-pot experiment of cadmium-loading (5 mgkg) with the addition of zinc (5 mgkg) carried out are introduced in this paper. For this, soil samples were taken from 4 sites of plough-land, grassland and forest land-use types. Accumulation characteristics of the two metals as well as their interaction with the soil properties were analysed. The results show that land-use has significant effect on zinc uptake. There is close correlation between the zinc and cadmium uptake of plants as well as that cadmium concentration of soils plays an important role in it. Zinc shows positive correlation while cadmium shows negative correlation with organic matter. Beside organic colloids, inorganic colloids i.e. clay fraction also showed close correlation.The effects of soil and climatic properties was studied on the winter wheat (Triticum aestivum L.) concerning on the heavy metal content of the plants. During this study the distribution of cobalt, copper, iron, manganese, nickel, and zinc was studied within a plant. Sampling was carried out in the same period of subsequent three years between 1995 and 1997. Our hypothesis was that the individuals of the same species has similar physiological answer for the same environmental properties. In this study we found no significant differences among the different plant’s parts and years. Our results can reveal that the ecological indication of plants could be major driver of agro-environmental studies to recognize unusual patterns of soil attributes.