Changes in epigeic spider community in primary succession on a brown-coal dump

A descriptive model of primary succession of spiders on a brown-coal dump is presented. Multivariate methods (cluster analysis and detrended correspondence analysis), and community indexes were applied to evaluate changes in community composition of epigeic spiders. Two different rehabilitation age stages were investigated. The cluster analysis helped to determine a case of horizontal asynchronous succession. The DCA was able to distinguish divergent trends of succession from the initial stage. Successional trends in species replacements were observed. In all aspects of succession there was found to be directional towards a "ruderal steppe" subclimax

Orchestina pavesii (Simon, 1873), an oonopid spider new to Slovakia (Araneae: Oonopidae)

Representatives of Oonopidae are tiny spiders, usually of a pale colour, with 6 oval eyes. Systematically, they belong to Dysderoidea, which include about 120 genera (CODDINGTON & LEVI 1991), but Oonopidae, alone, include 51 genera and more than 70 species (PLATNICK 1989). They are distributed all over the world, except for Antarctica, but most of the species come from the tropics. In Europe, there are 6 genera of oonopid spiders, represented by about 20 species (PLATNICK 1989). But only 6 species have been known from the Central Europe until recently (NENTWIG 1991). In Slovakia, only 2 species of oonopid spiders, Oonops domesticus Dalmas, 1916 and Triaeris stenaspis Simon, 1891, have been recorded so far (GAJDOS et al. 1999)

Spiders (Araneae) of the family Oonopidae in the Czech Republic

The oonopid spiders (Oonopidae) Tapinesthis inermis (Simon, 1882) and Triaeris stenapis Simon, 1891 are recorded for the Czech Republic for the first time. T. inermis was redetermined from misidentified material and T. stenaspis was discovered in a greenhouse

Stenochrus portoricensis new to the Czech Republic (Schizomida, Hubbardiidae)

A schizomid, Stenochrus portoricensis Chamberlin, 1922 (family Hubbardiidae), was collected in a greenhouse in Brno. This is the first discovery of a schizomid from the Czech Republic

Под давлением словацких националистов: статус и политическая активность русинов в Словакии в 1939–1945 гг.

The article examines the position of the Rusin minority in Slovakia during 1939–1945 and the political activities of the minority’s representatives in the conditions of the then authoritarian regime of the Hlinka Slovak People’s Party. The Rusin minority was an integral part of the Slovak population, but suffered from economic, social, and cultural backwardness. Nevertheless, its representatives had the ambition to be an active part of political life in the conditions that the legislation of the time allowed them. However, they constantly encountered the disinterest and distrust of the regime. Based on primary sources and published works, the article analyses and interprets the specific political activities of the Rusin minority, as well as the attitudes of the regime’s representatives towards the minority. It points to the fact that the Rusin minority found itself under the pressure of Slovak nationalism, because of which the possibilities of political life were limited, without the possibility of founding its own political party. The activities of the representatives of the minority were fully under the control of the regime

When smaller is more – investigating the interplay between continuous sensory cues and numerical information

Research on numerical cognition is not limited to symbolic numbers and mathematics but it also includes discrete and continuous magnitudes. Continuous magnitudes are ubiquitous in nature and serve as important cues in everyday life situations. When one tries to choose the plate with more cookies in the cafeteria, they usually do not count the cookies but rather arrive at a fair estimate by comparing such continuous magnitudes. For example, nine cookies on a plate will occupy a larger area and have to be placed denser to each other than five cookies. Recent research has shown that, as opposed to the classical view, the processing of symbolic numbers and non-symbolic numerosities is not independent from such sensory cues. The present dissertation consists of two studies that investigate what psychological processes underlie the interaction between sensory cues and numerical information. Study 1 aimed to replicate and extend the findings of Gebuis & Reynvoet who systematically manipulated the relationship between continuous and discrete magnitudes in a non-symbolic numerical comparison task. The main goal was to assess the stability and the robustness of the influence of sensory cues on numerical comparisons as the originally reported patterns suggest a complex interaction between these two kinds of information that are difficult to reconcile with the classic views on numerical processing. Indeed, the results confirmed that continuous magnitudes have a complex effect on numerical judgements and that their interaction can be either due to incomplete inhibition or due to integration of continuous magnitudes during numerical tasks. Study 2 turned to symbolic numbers and investigated whether inhibition underlies the interaction of continuous sensory properties and numerical information. To this end a novel paradigm was introduced that allowed to investigate well-established electrophysiological correlates of inhibition with numerical stimuli. The results provide evidence that inhibition underlies the interaction between sensory cues and numerical information. Additionally, they show that the paradigm introduced in Study 2 may suitable to investigate these processes across different developmental stages and numeracy levels

Dispersal and life-history traits in a spider with rapid range expansion

Background Dispersal and reproduction are key life-history traits that jointly determine species' potential to expand their distribution, for instance in light of ongoing climate change. These life-history traits are known to be under selection by changing local environmental conditions, but they may also evolve by spatial sorting. While local natural selection and spatial sorting are mainly studied in model organisms, we do not know the degree to which these processes are relevant in the wild, despite their importance to a comprehensive understanding of species' resistance and tolerance to climate change. Methods The wasp spider Argiope bruennichi has undergone a natural range expansion - from the Mediterranean to Northern Europe during the recent decades. Using reciprocal common garden experiments in the laboratory, we studied differences in crucial traits between replicated core (Southern France) and edge (Baltic States) populations. We tested theoretical predictions of enhanced dispersal (ballooning behaviour) and reproductive performance (fecundity and winter survival) at the expansion front due to spatial sorting and local environmental conditions. Results Dispersal rates were not consistently higher at the northern expansion front, but were impacted by the overwintering climatic conditions experienced, such that dispersal was higher when spiderlings had experienced winter conditions as occur in their region. Hatching success and winter survival were lower at the range border. In agreement with theoretical predictions, spiders from the northern leading edge invested more in reproduction for their given body size. Conclusions We found no evidence for spatial sorting leading to higher dispersal in northern range edge populations of A. bruennichi. However, reproductive investment and overwintering survival between core and edge populations differed. These life-history traits that directly affect species' expansion rates seem to have diverged during the recent range expansion of A. bruennichi. We discuss the observed changes with respect to the species' natural history and the ecological drivers associated with range expansion to northern latitudes

Intersexual Trophic Niche Partitioning in an Ant-Eating Spider (Araneae: Zodariidae)

ants that are polymorphic in body size and hence comprise potential trophic niches for the spider, making this system well-suited to study intersexual trophic niche partitioning.Comparative analysis of trophic morphology (the chelicerae) and body size of males, females and juveniles demonstrated highly female biased SSD (Sexual Size Dimorphism) in body size, body weight, and in the size of chelicerae, the latter arising from sex-specific growth patterns in trophic morphology. In the field, female spiders actively selected ant sub-castes that were larger than the average prey size, and larger than ants captured by juveniles and males. Female fecundity was highly positively correlated with female body mass, which reflects foraging success during the adult stage. Females in laboratory experiments preferred the large ant sub-castes and displayed higher capture efficiency. In contrast, males occupied a different trophic niche and showed reduced foraging effort and reduced prey capture and feeding efficiency compared with females and juveniles.Our data indicate that female-biased dimorphism in trophic morphology and body size correlate with sex-specific reproductive strategies. We propose that intersexual trophic niche partitioning is shaped primarily by fecundity selection in females, and results from sex-differences in the route to successful reproduction where females are selected to maximize energy intake and fecundity, while males switch from foraging to invest in mating effort