The factors that affect oviposition and consequently spatial distribution of the galls of many gall makers are poorly understood. Knowledge of these factors could result in a better understanding of the mechanisms that initiate and regulate the development of galls. We tested the hypotheses that, regardless of tree height, galls of Cynips quercusfolii L. produced agamically are distributed randomly in the crowns and on the veins of leaves of oak trees. This study was done in Poland on 15 pedunculate oak (Quercus robur) trees of various heights. We measured the areas of 1659 leaves, including 192 leaves with galls, and the distances along a vein from a gall to the petiole and from gall to leaf edge. The number of galls did not depend on tree height but depended on the position of the leaf within the crown (upper or lower). Regardless of the position in the crown, leaves with galls were significantly larger than those without galls. We conclude that galls were located at a fixed distance from the edge of leaves irrespective of leaf size, but the distance from the gall to the leaf petiole depended significantly on leaf size. We conclude that agamic females of C. quercusfolii prefer large leaves and choose the site on a leaf on which to deposit their eggs. This probably ensures that the developing gall obtains the required amount of nutrients and assimilates., Marian J. Giertych, Andrzej M. Jagodzinski, Piotr Karolevski., and Obsahuje seznam literatury
1_Prey preferences and feeding-related behaviour of a Central European species of Scydmaeninae, Euconnus pubicollis, were studied under laboratory conditions. Results of prey choice experiments involving 50 species of mites belonging to 24 families of Oribatida and one family of Uropodina demonstrated that beetles feed mostly on ptyctimous Phthiracaridae (over 90% of prey) and only occasionally on Achipteriidae, Chamobatidae, Steganacaridae, Oribatellidae, Ceratozetidae, Euphthiracaridae and Galumnidae. The average number of mites consumed per beetle per day was 0.27 ± 0.07, and the entire feeding process took 2.15–33.7 h and showed a clear linear relationship with prey body length. Observations revealed a previously unknown mechanism for capturing prey in Scydmaeninae in which a droplet of liquid that exudes from the mouth onto the dorsal surface of the predator’s mouthparts adheres to the mite’s cuticle. Morphological adaptations associated with this strategy include the flattened distal parts of the maxillae, whereas the mandibles play a minor role in capturing prey. Mechanisms for overcoming the prey’s defences depended on the body form of the mite. When attacking oribatids that adopt the ptychoid defence (encapsulation) Euconnus opened the prodorsum and pressed the anal and genital plates deeply into the idiosoma, whereas it fed on all other mites by entering their bodies through small gnathosomal or/and genital openings, after breaking off mouthparts or/and genital plates., 2_The preferential feeding of a specialized and locally abundant ant-like stone beetle on one family of Oribatida, documented here for the first time, has implications for the population dynamics of the prey and raises questions about predator-prey co-evolution and costs of an unusually prolonged period spent feeding when at risk from competition and attack by larger predators, typical of the habitats where Scydmaeninae occur., Pawel Jaloszynski, Ziemowit Olszanowski., and Obsahuje seznam literatury
There is much current discussion about the factors that control the distribution and abundance of animal species, particularly at the edges of their range. The significance of temperature for survival and development is compared in two closely related psyllid species (Craspedolepta nebulosa and C. subpunctata) living on the same host plant (Chamerion angustifolium) (Onagraceae) but displaying different distributions along latitudinal and altitudinal gradients. The following measurements were made at critical periods during the life cycle (a) winter supercooling points (SCPs), (b) tolerance of short (1 min) and long term (1-25) days exposure to sub-zero temperatures above the SCP, (c) tolerance of short term exposure to high spring/summer temperatures and (d) comparative field development rates among species and sites during the early critical part of the growing season. Successful completion of the life cycle is related to heat availability during the growing season. This appears to limit the distribution of the Craspedolepta species, rather than their survival response to thermal extremes. No significant differences were found between the two species in the supercooling point or in their long and short term survival responses at low or high temperatures., Jeremy M. Bird, Ian D. Hodkinson, and Lit
Ant assemblages were studied in Warsaw in the context of the effects of urban pressure. Four types of urban greenery were selected: (1) green areas bordering streets, (2) in housing estates, and (3) in parks, and (4) patches of urban woodland. In total, there were 27 species of ants. In terms of the total ant activity density, Lasius niger predominated in all the the lawn biotopes (1–3) and Myrmica rubra in the wooded areas. Ant species diversity was highest in parks and wooded areas and lowest in green areas bordering streets. In contrast, activity density was highest in green areas bordering streets and lowest in wooded areas. Some species are found only in a few habitats. Stenamma debile, Lasius brunneus, L. fuliginosus and Temnothorax crassispinus almost exclusively occurred in wooded areas, whereas L. niger was most often found in lawn biotopes. Myrmica rugulosa and Tetramorium caespitum were most abundant in green areas bordering streets, while in parks Lasius flavus, Formica cunicularia and Solenopsis fugax were most abundant. In general, the ant assemblages recorded showed a significantly nested pattern, with biotope type being a significant determinant of nestedness. The assemblages found in green areas in housing estates and bordering streets constituted a subsample of the assemblages in parks and wooded areas. Ant species were non-randomly distributed in this urbanized landscape and the species recorded in the most transformed biotopes constitute subsamples of those inhabiting less transformed biotopes. This finding emphasizes the importance of wooded areas for the maintenance of biodiversity in urban areas., Piotr Slipinski, Michal Zmihorski, Vojciech Czechowski., and Obsahuje seznam literatury
Stabilkataster und seine Möglichkeiten die Glaubwürdigkeit der historischen Angaben und die Bestätigung der Existenz der Standplätze und Vorkommen überzuprüfen. Beispiel der Indikationsgattung des rotäugigen Alpenfalters (Parnassius apollo L.).
Stabilkataster und die Möglichkeit, Glaubwürdigkeit der historischen Angaben über Vorkommen von Indikationsgattungen und über Existenz der Standplätze überzuprüfen. Beispiel des rotäugigen Alpenfalters (Parnassius apollo L.) auf dem Libinberg bei Prachatitz.
In some species of insects, individuals with fully developed wings and capable of flying coexist with flightless individuals that lack functional wings. Their diets may differ if long-winged individuals are more mobile and therefore likely to be better at finding and utilizing high quality food resources, or if they have different food preferences or physiological requirements. Despite its potential importance, differences in the diet of dispersal phenotypes have not been unequivocally demonstrated under natural conditions. To test for dietary divergence, we compared natural abundances of carbon and nitrogen stable isotope ratios (d13C and d15N) in long- and short-winged free ranging Tetrix subulata pygmy grasshoppers collected as adults from two natural populations. Overall, this comparison of stable isotopes indicated long-term differences in the diet of the two wing morphs in both populations, but not between males and females of the same morph. We conclude that it is likely that the dietary niches of the long winged and flightless individuals differ under natural conditions. This may reduce intra-specific competition, offset the expected trade-off between flight capacity and reproduction and promote ecological speciation. Address, Einat Karpestam, Anders Forsman., and Obsahuje seznam literatury
The effects of 5 pmols of adipokinetic hormone (Lom-AKH-I) on both the locomotion and mobilization of lipids were studied in 10-day-old diapausing adult females of the short-winged (brachypterous) morph of Pyrrhocoris apterus (L.). The results revealed that AKH stimulation of locomotion in this bug is wing-morph independent. The stimulatory effect of AKH on locomotion was shown to be positively correlated with its effect on lipid mobilization., Radomír Socha, Dalibor Kodrík, Rostislav Zemek, and Lit