Emanuel Kula

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 10xa0mgxa0ml−1, by which differentiated manganese contents (307; 632; 4,087 and 8,124xa0mgxa0kg−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 (8xa0% mortality for caterpillars with no Mn contamination (T0) and 62xa0% mortality for subjects with the highest contamination by manganese (T3)), by prolonged development of the first–third instar (18.7xa0days (T0) and 27.8xa0days (T3)) and by increased food consumption of the first–third instar {0.185xa0g of leaf dry matter (T0) and 0.483xa0g 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 0.5xa0% of the intake level even at its maximum inputs in food.

Reaction of Leaf Weevil Phyllobius arborator (Coleoptera: Curculionidae) to Manganese Content in Diet

Abstract Reaction of leaf weevil (Phyllobius arborator (Herbst)) to increased concentration of manganese in diet was investigated in laboratory rearing with controlled temperature, humidity, and light conditions. Food for leaf weevils in rearing (leaves of birch Betula pendula Roth) was contaminated by soaking the leaves in solutions of MnCl2.4H2O with graded concentration of manganese. Direct influence of food was characterized by the consumed amount of leaves, period of feeding, and weight of P. arborator adults. At the same time, the levels of manganese in unconsumed food, excrement, and bodies of adults were determined. Even very high content of manganese in food did not cause significantly different reaction of P. arborator adults in comparison to individuals in control treatment. No significant difference in the quantity of the consumed food, weight of adults, and duration of their feeding period was found between the treatments within the experiment. The content of manganese found in food, excrement, and adult beetles indicate that P. arborator avoided manganese intoxication through food by both—voiding manganese through the feces and sequestering it at relatively high concentrations in unspecified parts of their body.

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 cockchafers 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.