Element contents and their seasonal dynamics in leaves of alder Alnus glutinosa (L.) Gaertn.

Alnus glutinosa is an actinorhizal plant that fixes N via actinomycetes. Compared to other trees, A. glutinosa is more resistant to environmental stress and able to uptake soil nutrients more easily. Alnus glutinosa grows well not only in natural stands but also in degraded environment or soil in need of restoration. Changes in the contents of selected macro-, micro-, and non-nutrient elements in the leaves of A. glutinosa during the vegetation season were monitored in the Ore Mountains (Czech Republic), an area affected by extreme air pollution in the past. Decreased foliar content of N, P, K, and Cu, and increased content of Ca, Mn, Zn, and Al were observed; the content of other elements (S, Mg, Pb, and Cd) varied during the growing season or remained constant. From the viewpoint of nutrition, the content of N, S, Ca, and Mg macroelements was adequate; concentrations of P and K were low. Excessive amounts of Mn and Zn were measured, and the level of Cu was good. Non-nutrient elements Pb and Cd were present at the background level, and the level of Al was high. N/P, N/Ca, N/Mg, and Ca/Mg ratios were balanced, S/N value showed the lack of S, and N/K ratio indicated low content of K, which caused also suboptimal K/Ca and K/Mg values. The P/Al ratio varied from balanced to lower values. The content of individual elements and monitored changes were influenced by the amount of elements in the soil, moisture conditions, foliage phenology, and altitude.

Reactions of Melolontha hippocastani adults to high manganese content in food.

Rapid adaptation of insect species to environmental changes can be advantageous for their development. Forest cockchafer (Melolontha hippocastani) is herbivorous insect species with high food intake that has been widely studied within European conditions. It can cause huge economic and ecological losses especially in oak-dominated forest stands. Food preference of this species is mainly comprised of trees with a potential to accumulate manganese in their assimilation apparatus. In order to determine cockchafer's reactions to increased Mn concentration in its food, the adults were reared in laboratory conditions controlled for temperature, humidity, and light on a natural diet of oak (Quercus petraea) leaves. Food was contaminated by soaking in solutions of MnCl2·4H2O in concentrations from 0.5 to 10mgml-1. Food consumption, activity period of adults, quantity of eggs laid, body weights of individuals, as well as Mn concentrations in unconsumed food, excrement, and the bodies of cockchafers were determined to indicate how these change in reaction to food quality altered in terms of Mn content. The results showed that very high Mn content in the diet significantly influenced food consumption by M. hippocastani adults and thereby their development. This was in spite of the tendency of individuals to expel Mn through the faeces and incorporate it into undetermined parts of their bodies. Negative reactions of the experimental population were determined in treatments fed leaves with Mn concentration of 1800ppm and more. Our experiment proved that Mn can greatly influence the phytophagous cockchafer (decreased feeding time, food consumption, and fertility).

Revisionary study on European species of the Empria candidata complex (Hymenoptera, Symphyta, Tenthredinidae).

Two species of the Empria candidata species complex, E. candidata (Fallén, 1808) and E. magnicornis (Eversmann, 1864) spec. rev., comb. nov., are revised and redescribed. The males and larvae of both species are identified, described and the males are associated with the corresponding females. The species are redefined based on the revision of the available types. Lectotypes are designated for Tenthredo (Allantus) repanda Klug, 1816 and Tenthredo (Macrophya) magnicornis Eversmann, 1864.

Development of Lymantria dispar affected by manganese in food.

We studied the response of gypsy moth (Lymantria dispar (Linnaeus) (Lepidoptera: Lymantriidae)) to the content of manganese in food in the laboratory breeding of caterpillars. The food of the caterpillars {Betula pendula Roth (Fagales: Betulaceae) leaves} was contaminated by dipping in the solution of MnCl2 · 4H2O with manganese concentrations of 0, 0.5, 5 and 10 mg ml(-1), by which differentiated manganese contents (307; 632; 4,087 and 8,124 mg kg(-1)) were reached. Parameters recorded during the rearing were as follows: effect of manganese on food consumption, mortality and length of the development of caterpillars, pupation and hatching of imagoes. At the same time, manganese concentrations were determined in the offered and unconsumed food, excrements, and exuviae of the caterpillars, pupal cases and imagoes by using the AAS method. As compared with the control, high manganese contents in the food of gypsy moth caterpillars affected the process of development particularly by increased mortality of the first instar caterpillars (8 % mortality for caterpillars with no Mn contamination (T0) and 62 % mortality for subjects with the highest contamination by manganese (T3)), by prolonged development of the first-third instar (18.7 days (T0) and 27.8 days (T3)) and by increased food consumption of the first-third instar {0.185 g of leaf dry matter (T0) and 0.483 g of leaf dry matter (T3)}. The main defence strategy of the caterpillars to prevent contamination by the increased manganese content in food is the translocation of manganese into frass and exuviae castoff in the process of ecdysis. In the process of development, the content of manganese was reduced by excretion in imagoes to 0.5 % of the intake level even at its maximum inputs in food.

Detecting insect pollinator declines on regional and global scales.

Recently there has been considerable concern about declines in bee communities in agricultural and natural habitats. The value of pollination to agriculture, provided primarily by bees, is >$200 billion/year worldwide, and in natural ecosystems it is thought to be even greater. However, no monitoring program exists to accurately detect declines in abundance of insect pollinators; thus, it is difficult to quantify the status of bee communities or estimate the extent of declines. We used data from 11 multiyear studies of bee communities to devise a program to monitor pollinators at regional, national, or international scales. In these studies, 7 different methods for sampling bees were used and bees were sampled on 3 different continents. We estimated that a monitoring program with 200-250 sampling locations each sampled twice over 5 years would provide sufficient power to detect small (2-5%) annual declines in the number of species and in total abundance and would cost U.S.$2,000,000. To detect declines as small as 1% annually over the same period would require >300 sampling locations. Given the role of pollinators in food security and ecosystem function, we recommend establishment of integrated regional and international monitoring programs to detect changes in pollinator communities.

Supercritical fluid extraction of amino acids from birch (Betula pendula Roth) leaves and their liquid chromatographic determination with fluorimetric detection.

A method for supercritical fluid extraction (SFE) of amino acids was adapted and optimal experimental conditions were selected for a matrix consisting of dry leaves. The matrix-dependent SFE method uses a mixture of MeOH-H(2)O-acetonitrile (10:10:1 v/v/v) as a modifier (0.5 mL in situ, 300 muL on-line) at 70 degrees C and 40 MPa and no HCl is needed as an entrainer. The amino acids were quantified using high-performance liquid chromatography with fluorimetric detection (HPLC/FLD) after gradient elution on Zorbax Eclipse AAA columns (4.6x150 mm, 3.5 mum) with aqueous Na(2)HPO(4 )buffer of pH 7.8 and ACN-MeOH-water as a mobile phase. In comparison with Soxhlet extraction, SFE gave higher recovery and selectivity, but it required longer extraction time (90 min) and it was more labor-intensive (clean-up step after the pre-concentration). Both methods should be used separately or in combination according to the matrix, number of samples, and levels of ballast compounds.