Body size is one of the most investigated traits in studies of sexual selection in fruit flies of the genus Drosophila. In D. melanogaster, size has often been correlated with male mating success, i.e. larger males were more successful in achieving copulations both in laboratory and field conditions. In the present paper, we investigated if male body size is a sexually selected trait in competitive conditions, when full-sibs that developed at two different temperatures (18 and 25°C) competed for females. Males developed at a lower temperature were significantly larger than those reared at a higher temperature, but they were not more successful in mating. We conclude that when body size is significantly induced by temperature variability, it is not correlated with male mating success., Sofija Pavkovic-Lučic, Vladimir Kekic., and Obsahuje seznam literatury
We have found that the determination of thiodiglycolic acid (TDGA) in urine may help to characterize metabolic imbalance of substances participating in methionine synthesis, which leads to hyperhomocystinuria. From the metabolic scheme, based on a proper combination of known facts, we attempted to theoretically explain and to demonstrate the possibilities of TDGA formation via different ways of homocysteine transformation. This scheme was used in evaluating the results obtained by testing urine of a woman suffering from impaired function of methionine synthase reductase (CblE type of homocystinuria). The amount of TDGA excreted in her morning urine was very sensitive to the changes in her treatment based upon a combination of N5-formyl tetrahydrofolate, betaine and vitamin B12. Vitamin B12 given in the evening either alone or together with betaine increased the TDGA excretion in the morning urine up to ten times. On the other hand, in the absence of vitamin B12, betaine in combination with N5-formyl tetrahydrofolate hindered the appearance of TDGA in the morning urine. Generally, the determination of TDGA in urine of an appropriately pretreated patient may indicate the degree of success of the treatment., T. Navrátil, M. Petr, Z. Šenholdová, K. Přistoupilová, T. I. Přistoupil, M. Heyrovský, D. Pelclová, E. Kohlíková., and Obsahuje bibliografii a bibliografické odkazy
The Asian ladybird Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is regarded as an invasive species in many parts of the world. In a previous study we hypothesised that H. axyridis enters diapause at the end of October and then shifts to a quiescent state in December in northwestern Europe. In the present study we test this idea of a short, early period of diapause by sampling beetles from their hibernation sites immediately after their migratory flights in October, subsequently keeping them in outdoor cages, and then, after certain time-intervals, measuring the pre-oviposition time under optimal egg-laying laboratory conditions at 25°C. We did this at both short (12L) and long (16L) photoperiods, since a photoperiodic response is an indicator of true diapause, rather than quiescence. A significant, albeit small, difference in pre-oviposition period between the two photoperiods, which disappears in December, corroborates our earlier hypothesis that the ladybirds are in a state of diapause until mid-December. Compared with that of native ladybirds the diapause of H. axyridis generally is relatively short and weak; moreover, it appears to have become shorter over the last decade. This flexibility in diapausing behaviour may be an important factor that contributes to the invasive success of H. axyridis., C. Lidwien Raak-Van Den Berg ... [et al.]., and Obsahuje seynam literatury
The size and fecundity of Hemiberlesia lataniae (Signoret) (Hemiptera: Diaspididae) on partially resistant and susceptible kiwifruit (Actinidia spp.) varieties was measured. The size ratio of mature H. lataniae grown on a partially resistant genotype, compared with those on a susceptible genotype, was 0.67-0.51 for 2nd instar exuviae area, 0.32 for adult body area and 0.18 for estimated body volume. The fertility ratio was 0.1, but the pre-oviposition period and the size of the crawlers were the same. Diaspidid scale insects' unusual ability to continue growing after the final moult appears to be a key feature allowing these insects to show extreme size plasticity while retaining the ability to reproduce even when very small. These observations challenge current theories of insect development that postulate the need to achieve a critical weight threshold before the final moult. We suggest that this strategy may have assisted the evolution of polyphagy within the Diaspididae. and M. Garry HILL, Rosa C. HENDERSON, Nicola A. MAUCHLINE.
Under normal conditions, antioxidants at the corneal surface are balanced with the production of reactive oxygen species without any toxic effects. Danger from oxidative stress appears when natural antioxidants are overwhelmed leading to antioxidant/prooxidant imbalance. The aim of the present study was to examine the activities of enzymes contributing to the antioxidant/prooxidant balance in normal corneal epithelium of various mammals. The enzyme activities of antioxidant superoxide dismutase and glutathione peroxidase, as well as prooxidant xanthine oxidoreductase/xanthine oxidase were examined using biochemical methods. Results show that superoxide dismutase activity is high in rabbits and guinea pigs, whereas in pigs the activity is low and in cows it is nearly absent. In contrast, glutathione peroxidase activity is high in cows, pigs and rabbits, whereas in guinea pigs the activity is low. As far as prooxidant enzymes are concerned, elevated xanthine oxidoreductase/xanthine oxidase activities were found in rabbits, lower activities in guinea pigs, very low activity in cows and no activity in pigs. In conclusion, the above results demonstrate inter-species variations in activities of enzymes participating in antioxidant/prooxidant balance in the corneal epithelium. It is suggested that the levels of antioxidant and prooxidant enzymes studied in the corneal epithelium might be associated with the diurnal or nocturnal activity of animals. UV rays decompose hydrogen peroxide to damaging hydroxyl radicals and perhaps for this reason large animals with diurnal activity (cow, pig) require more effective peroxide removal (high glutathione peroxidase activity) together with the suppression of peroxide production (low superoxide dismutase activity, low xanthine oxidoreductase activity)., J. Kovačeva, J. Pláteník, M. Vejražka, S. Štípek, T. Ardan, Č. Čejka, A. Midelfart, J. Čejková., and Obsahuje bibliografii a bibliografické odkazy
The use of light traps for controlling insect pests is restricted since they kill both pests and beneficial insects. It may be a possible to reduce the numbers of beneficial insects trapped by adjusting nightly trapping time based on differences recorded in the timing of the nocturnal flight peaks of target pests and beneficials. To test this, insects were collected hourly over night using black light traps at three locations in China from 2003 to 2005. Groups of lepidopteran and coleopteran pests were selected as the target pests that we would control by trapping and groups of beneficial predatory insects the catches of which needed to be reduced. The highest numbers of Coleoptera were caught between 20:00 and 22:00 h and of most Lepidoptera between 02:00 and 04:00 h. The hourly numbers of predatory insects caught by light traps were evenly distributed throughout the night. A model was developed to describe the relationships between the cumulative proportions of insects caught and time of night. The model accurately describes the flight activity of insects that were mainly caught before midnight, after midnight and evenly throughout a night by using different parameters for the three different insect groups. A beneficial-friendly trapping strategy was developed to reduce the numbers of beneficial insects trapped, which was based on differences in the nocturnal flight activity of pests and beneficial insects and validated by a field study in Shandong province. Results show that this trapping strategy reduced the number of beneficial insects caught by 46% and the electricity consumption by 50% compared to the traditional strategy. Thus this strategy is more beneficial-friendly than the traditional trapping strategy for controlling pests., Gang Ma, Chun-Sen Ma., and Obsahuje seznam literatury
Lianas perform better than co-occurring trees in secondary forests or disturbed areas. Lianas and trees differ strikingly in water use strategy, which may result in a significant difference in photosynthetic light use between both growth forms. However, the difference in the photosynthetic efficiency and light energy dissipation between these two growth forms is poorly understood. Moreover, photorespiration is an important mechanism of photoprotection under conditions of high light. In this study, we used Bridelia stipularis (Linn.) Bl. (liana) and Strophioblachia fimbricalyx Boerl. (tree) in order to measure the response curves of the gas exchange and photosynthetic electron flow to the incident light gradients and intercellular CO2 concentration, as well as the hydraulic conductivity. We tested whether the photochemical efficiency and photorespiration differed between both growth forms. Our results clearly demonstrated that B. stipularis possessed a significantly higher stem and leaf specific hydraulic conductivity, total electron flow, and maximum rate of ribulose-1,5-bisphosphate regeneration compared to the sympatric tree S. fimbricalyx. Correspondingly, B. stipularis exhibited a significantly higher photochemical quenching coefficient and electron flow to photorespiration relative to S. fimbricalyx under saturating light levels. We suggested that photorespiration might play an important role in photoprotection for both species under high light, but particularly for B. stipularis. These findings could enrich our knowledge of the superior photosynthetic and growth performance of lianas over the co-occurring trees., S.-B. Zhang, J.-L. Zhang, K.-F. Cao., and Seznam literatury