To understand the evolution of insect gut symbionts it is important to determine how they are passed on to the next generation. We studied this process in Erwinia species bacteria that inhabit the gut of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). This is a polyphagous herbivore and a world-wide pest in agricultural crops. With bacteria in the gut, the thrips larval development time can be shorter and its oviposition rate higher compared to bacteria-free thrips. Bacteria are not directly transmitted from mother to offspring, but larvae acquire bacteria from the leaves right after they hatch. These gut bacteria are present on the leaves on feeding sites used by other thrips before the larvae arrive, probably because these other thrips have deposited bacteria via faeces or regurgitation. In this study we addressed the question whether the transmission route of symbiotic bacteria influences the thrips feeding behaviour, and determined the feeding and oviposition preference of thrips, by giving them a choice between leaves with and leaves without prior grazing by other western flower thrips. This was studied for thrips with and thrips without gut bacteria. Young larvae prefer to feed on leaves that where grazed before by other thrips and females prefer to oviposit on these grazed leaves. These results are in contradiction to earlier studies that have found that thrips larvae fitness is lower on thrips damaged plants than on clean plants. This behaviour does however promote the establishment of gut bacteria in the thrips. The factors determining the preference for thrips-damaged leaves may be the physical leaf damage or odours that are produced by the plant, the bacteria or both.
This paper discusses the strengths and weaknesses of pan-European datasets, in particular ECHP and EU-SILC, for research in housing. Although ‘housing’ is a complex topic when studied from a European comparative perspective, I argue that there is no inherent reason why housing should be less amenable to cross-national research than other equally complex topics in comparative social science research, such as research into family change and stability, or the impact of educational systems on social stratification. Given appropriate theory, conceptualisation and contextualisation, along with strong methodologies, meaningful and informative research in housing with ECHP and EU-SILC are possible. There are however a number of limitations, which are mainly related to the fact that both datasets are geared towards the ‘production’ of a ‘system of social indicators’ informing European and national governments. Because of these limitations, ECHP and in particular EU-SILC are less attractive and less useful for academic research then they could potentially be.
Starling’s original definition of a hormone from 1905 was “a hormone is a substance produced by glands with internal secretion, which serve to carry signals through the blood to target organs”. Today, this definition is understood to be lacking, but newer definitions also do not encompass the entire meaning of hormones as specific carriers of information. One main problem is that there is no delineation between hormones and other signaling molecules such as cytokines, growth factors or autacoid compounds. It seems that a precise definition is not even possible, since some cytokines and growth factors, such as the cytokines erythropoietin, lipocalin-2 and asprosin or fibroblast growth factor 23, act as hormones under certain conditions., Luboslav Stárka, Michaela Dušková., and Obsahuje bibliografii
The aim of this study was to check what decide about breeding success in red- backed shrike Lanius collurio: nest-site concealment or parent’s aggressive behaviour. The study was carried out in eastern Poland in 1999–2003, on study plot consisted of 855 ha of extensively agricultural landscape. The effect of nest site concealment and defence of brood by parents on breeding success was determined. In observations only natural nests were used. During the two of 10 days periods after commence of egg laying, no effect of index nest concealment and index of parents aggressiveness was observed. However, in first seven days of life of nestlings, was noticed that breeding success was depended on aggressiveness of parents, in relation to index nest concealment. The results showed behavior (aggression) as an important factor in breeding success of the red-backed shrike.
Optical mapping is a fluorescence-based physiological method to image spreading of action potential in excitable tissues, such as the heart and central nervous system. Because of the requirements for high speed imaging in low light conditions, highly sensitive high-speed cameras together with an optical system with maximum photon efficiency are required. While the optimization of these two components is relatively straightforward, the choice of the perfect light source is less simple; depending on the other (usually fixed) components, various parameters may acquire different weight in decisionmaking process. Here we describe the rationale for building an optical mapping setup and consider the relative advantages and disadvantages of three different commonly available light sources: mercury vapor lamp (HBO), xenon lamp (XBO), and light emitting diode (LED). Using the same optical system (fluorescence macroscope) and high-speed camera (Ultima L), we have tested each of the sources for its ability to provide bright and even illumination of the field of view and measured its temporal fluctuations in intensity. Then we used each in the actual optical mapping experiment using isolated, perfused adult mouse heart or chick embryonic heart to determine the actual signal to noise ratio at various acquisition rates. While the LED sources have undergone significant improvements in the recent past, the other alternatives may still surpass them in some parameters, so LEDs may not be the automatic number one choice for every application., Veronika Olejnickova, David Sedmera., and Obsahuje bibliografii