Xylosandrus germanus in Central Europe: Spread into and within the Czech Republic

Invasive organisms represent great threats to ecosystems and great challenges to forest management. In Europe, the black timber bark beetle (Xylosandrus germanus) is an invasive secondary pest that mostly attacks the logs of felled trees. We showed the invasion history for Europe and using many local surveys, we summarize the current distribution and other available information on X. germanus in the Czech Republic. We report that this species is distributed from the lowlands to the mountains in the Czech Republic; it is widespread in the eastern half of the country, where it is more abundant in the warmer south and southeast areas than in the cooler areas. Most (78%) of the known localities are at elevation below 400 m a.s.l. Although an ice storm greatly increased X. germanus abundance near the border with Austria, its high abundance did not result in damage to standing trees. Presence of X. germanus in the Czech Republic for over 10 years has not led to heavy tree infestation.     

Emerging genetic patterns of the European Neolithic: perspectives from a late Neolithic Bell Beaker burial site in Germany

The transition from hunting and gathering to agriculture in Europe is associated with demographic changes that may have shifted the human gene pool of the region as a result of an influx of Neolithic farmers from the Near East. However, the genetic composition of populations after the earliest Neolithic, when a diverse mosaic of societies that had been fully engaged in agriculture for some time appeared in central Europe, is poorly known. At this period during the Late Neolithic (ca. 2,800-2,000 BC), regionally distinctive burial patterns associated with two different cultural groups emerge, Bell Beaker and Corded Ware, and may reflect differences in how these societies were organized. Ancient DNA analyses of human remains from the Late Neolithic Bell Beaker site of Kromsdorf, Germany showed distinct mitochondrial haplotypes for six individuals, which were classified under the haplogroups I1, K1, T1, U2, U5, and W5, and two males were identified as belonging to the Y haplogroup R1b. In contrast to other Late Neolithic societies in Europe emphasizing maintenance of biological relatedness in mortuary contexts, the diversity of maternal haplotypes evident at Kromsdorf suggests that burial practices of Bell Beaker communities operated outside of social norms based on shared maternal lineages. Furthermore, our data, along with those from previous studies, indicate that modern U5-lineages may have received little, if any, contribution from the Mesolithic or Neolithic mitochondrial gene pool.     

The Neolithic Demographic Transition in the Central Balkans: population dynamics reconstruction based on new radiocarbon evidence

In this paper, we test the hypothesis of the Neolithic Demographic Transition in the Central Balkan Early Neolithic (6250–5300 BC) by applying the method of summed calibrated probability distributions to the set of more than 200 new radiocarbon dates from Serbia. The results suggest that there was an increase in population size after the first farmers arrived to the study area around 6250 BC. This increase lasted for approximately 250 years and was followed by a decrease in the population size proxy after 6000 BC, reaching its minimum around 5800 BC. This was followed by another episode of growth until 5600 BC when population size proxy rapidly declined, reaching the minimum again around 5500 BC. The reconstructed intrinsic growth rate value indicates that the first episode of growth might have been fuelled both by high fertility and migrations, potentially related to the effects of the 8.2 ky event. The second episode of population growth after 5800 BC was probably owing to the high fertility alone. It remains unclear what caused the episodes of population decrease.This article is part of the theme issue ‘Cross-disciplinary approaches to prehistoric demography''.     

Ancient Maltese genomes and the genetic geography of Neolithic Europe

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Musculoskeletal stress markers in Natufian hunter-gatherers and Neolithic farmers in the Levant: the upper limb

This paper attempts to quantify the changes in activity patterns of early farming populations in the Levant through the musculoskeletal stress markers (MSM) of the upper limb as seen in skeletal remains. The transition to an agricultural way of life resulted in higher loads on the upper limb in Neolithic populations compared to the Natufian hunter-gatherer populations that preceded them. The MSM pattern for males and females indicates a gender-based division of labor both in the Natufian and the Neolithic. It may also suggest that people in the Neolithic period were engaged in different (new) activities and occupations compared to the Natufian.     

Predicting invasions by woody species in a temperate zone: a test of three risk assessment schemes in the Czech Republic (Central Europe)

To assess the validity of previously developed risk assessment schemes in the conditions of Central Europe, we tested (1) Australian weed risk assessment scheme (WRA; Pheloung et al . 1999); (2) WRA with additional analysis by Daehler et al . (2004); and (3) decision tree scheme of Reichard and Hamilton (1997) developed in North America, on a data set of 180 alien woody species commonly planted in the Czech Republic. This list included 17 invasive species, 9 naturalized but non-invasive, 31 casual aliens, and 123 species not reported to escape from cultivation. The WRA model with additional analysis provided best results, rejecting 100% of invasive species, accepting 83.8% of non-invasive, and recommending further 13.0% for additional analysis. Overall accuracy of the WRA model with additional analysis was 85.5%, higher than that of the basic WRA scheme (67.9%) and the Reichard–Hamilton model (61.6%). Only the Reichard–Hamilton scheme accepted some invaders. The probability that an accepted species will become an invader was zero for both WRA models and 3.2% for the Reichard–Hamilton model. The probability that a rejected species would have been an invader was 77.3% for both WRA models and 24.0% for the Reichard–Hamilton model. It is concluded that the WRA model, especially with additional analysis, appears to be a promising template for building a widely applicable system for screening out invasive plant introductions.     

Reproduction and Pollination in Central European Populations of Silene and Saponaria Species

Flower morphology, flowering phenology, flower visitors, reproductive systems, and stigmatic receptivity of six species of Silene and Saponaria (Silene alba, S. dioica, S. vulgaris, S. nutans, S. noctiflora. Saponaria officinalis) were studied from April to October 1993 and from April to June 1994 in natural populations around Giessen in Hessen/Central Germany and, additionally, in individuals grown from seeds in the Botanical Garden of the University of Giessen. With the exception of Saponaria officinalis and S. noctiflora, all species were regularly visited and pollinated by crepuscular and nocturnal moths and hawkmoths, but only one species, S. alba, was exclusively pollinated by these night-active insects. The other species showed mixed pollination syndromes in which nocturnal and diurnal insects both promoted pollen transfer. Geitonogamy or even autogamy occurred in the gynodioecious and hermaphrodite species S. vulgaris, S. nutans, S. noctiflora, and Saponaria officinalis. Silene noctiflora, the only annual species, is pseudocleistogamous; the majority of its flowers did not open, and fruit set occurred after selfing in bud.     

Types of geographical distribution of leaf beetles (Chrysomelidae) in Central Europe

A comparison of the geographical distribution patterns of 647 species of Chrysomelidae in Central Europe revealed 13 types of distribution: (1) widely distributed, (2) southern, (3) southeastern, (4) southwestern, (5) northern, (6) eastern, (7) south east quarter, (8) south west quarter, (9) fragmented, (10) montane, (11) subalpine & alpine, (12) scattered, (13) unusual, and irregular patterns produced by insufficient data. Some of these distributions are trivial (e. g. northern, eastern, etc., alpine) but others are surprising. Some cannot be explained, e. g. the remarkable gaps in the distribution of Chrysolina limbata (Fabricius, 1775) and in Aphthona nonstriata (Goeze, 1777). Although our 63.000 records are necessarily tentative, we found that the distribution maps from these data reflect in many cases the common knowledge on the occurrence of leaf beetles in specific areas.     

Evolutionarily singular strategies and the adaptive growth and branching of the evolutionary tree

We present a general framework for modelling adaptive trait dynamics in which we integrate various concepts and techniques from modern ESS-theory. The concept of evolutionarily singular strategies is introduced as a generalization of the ESS-concept. We give a full classification of the singular strategies in terms of ESS-stability, convergence stability, the ability of the singular strategy to invade other populations if initially rare itself, and the possibility of protected dimorphisms occurring within the singular strategy's neighbourhood. Of particular interest is a type of singular strategy that is an evolutionary attractor from a great distance, but once in its neighbourhood a population becomes dimorphic and undergoes disruptive selection leading to evolutionary branching. Modelling the adaptive growth and branching of the evolutionary tree can thus be considered as a major application of the framework. A haploid version of Levene's soft selection model is developed as a specific example to demonstrate evolutionary dynamics and branching in monomorphic and polymorphic populations.     

Fresh investigations into the natural and anthropogenically influenced vegetation of the earlier Holocene in the Elbe-Saale Region,Central Germany

At present the central part of the Elbe-Saale area is characterized by subcontinental climatic conditions. Palynological investigations at Zöschen show that, even in pre-Neolithic times, the composition of the primeval forest in this part of Germany had its own distinctive features. On the basis of the palynological results, the existence of natural steppe Holocene is improbable, the region being covered by forests since ca. 9 500 B.P., i.e. the Preboreal. The appearance of anthropochores or culture dependent plants and the beginning of flood loam sedimentation as a result of soil erosion indicate human impact from ca. 6 000 B.P., i.e. the end of the older Atlantic. At Eilsleben changes of tree and shrub frequencies are combined with the occurrence of anthropogenic indicator herb species. These palynological features suggest agricultural expansion phases that are interrupted by regression phases in the early and middle Neolithic (ca. 6 500-2 500 B.P.).     

果实(种子)化学防御与食果实动物的适应对策

种子植物在果实(种子)成熟后需要防御食果实动物捕食种子,同时要传播种子至适宜萌发的生境。很多植物依赖食果实动物传播种子,称动物传播植物。果实(种子)化学防御是抵御种子捕食者的重要手段。果实(种子)中次生物质包括各种生物碱、生氰糖苷、萜类和酚类等,种类繁多;次生物质的含量随果实成熟过程而变化。次生物质可以抵御动物的捕食,其毒性对种子传播者和种子捕食者没有选择性,即具泛毒性。果肉中的次生物质也可以起到轻泻剂的作用,缩短种子在动物消化道的滞留时间,以影响传播效率。果实(种子)次生物质的产生不受植物环境条件的影响,其产生与果实质量有关。在温带地区,通常SS型果实次生物质含量低,而FL型果实含量高。食果实动物可通过调整捕食行为、摄取环境中特殊物质和获得丰富营养等3个方面适应次生物质。果实(种子)中次生物质的研究对动植物相互作用、协同进化理论具有重要的意义。     

Natural enemy spectrum ofAphis spiraephaga (Hom.: Aphididae), an exotic immigrant aphid in Central Europe

Aphis spiraephaga Müller, an aphid of Central Asian origin, dispersed west-wards and reached Central Europe probably before 1956. It now occurs in most European countries. Research undertaken in the Czech Republic mainly in 1991–1993, revealed that the aphid is attacked by a variety of natural enemies, including both parasitoids (Aphelinidae, Aphidiidae) and predators (Anthocoridae, Chrysopidae, Hemerobiidae, Cantharidae, Coccinellidae, Chamaemyidae, Itonididae, Syrphidae). All the natural enemies were identified to species. Attendance by ants (Lasius sp.) was common.A. spiraephaga was also successfully utilised as a new alternate host of two newly introduced parasitoid biocontrol agents (Aphidius colemani Viereck,Lysiphlebus testaceipes (Cresson).     

The Lower Palaeolithic assemblages in Central Europe in stratigraphic and palaeogeographic background

The hominin presence during Lower Palaeolithic in Central Europe was sporadic and followed cold-warm climatic cycle connected with spreading of Scandinavian ice sheet. Up to now there had been discovered about 50 archaeological assemblages from 17 sites from 700 ka years, mostly from second part of it, during c. 300 ka between MIS 15 and 9. The Lower Paleolithic hominins visited Central Europe during warmer periods with deciduous or coniferous forests, even during open domination of open or partly open landscape. Incredible finds, like Bilzingsleben and Schöningen show how complex was life of early hunter-gatherers. In opposite to the previous concept, according to which Lower Palaeolithic hominins were mostly scavengers. The discovery of wooden tools, like spears in lakeshore in opencast mine Schöningen, denies this concept. Contrary to that, early hominins were smart hunters following animal herds and hunted distant way and experienced gatherers. Local lithic technology based on core-flake processing in opposite to Western and Southern Europe dominated by handaxes. Moreover, the preferred usage of “small tools”, which are difficult to use only by fingers may be explained by identification of wooden hafts on few lithic artifacts in Schöningen. However, very long duration of unchanged lithic technology is surprising. An intense accumulation of glacial, eolian and alluvial sediments covered large part of Central Europe and this way Lower Palaeolithic sites are very difficult to discover. All known sites were identified in deep travertine quarries or opencast mines. Future research must be focused on systematic prospection of such outcrops.     

Biochemical genetic variation in populations of Larus argentatus and Larus fuscus in northwestern Europe

The techniques of biochemical population genetics were used to examine the relationships between two apparently closely related species and their component subspecies which form the Larus argentatus/fuscus species complex in northwest Europe. The systematics and taxonomy of these populations in this part of the circum-polar ring are complex and it was thought that this type of analysis might clarify the taxonomic relationships. Samples were obtained from breeding colonies along a transect from northern France (47°N), through Britain to arctic Norway (70°N), with additional samples from the Camargue on the Mediterranean coast (42°N). Twenty-one enzyme systems were examined using starch gel electrophoresis. No interspecific differences were found and only one locus (glutamate oxaloacetate transaminase) was polymorphic. There were no allelic differences within geographical groups of populations, although there were some differences between some of the subspecies. The low levels of heterozygosity ( H = 0.0081 and H = 0.0031) are considered to arise from a combination of two factors: the low levels of heterozygosity which appear to be characteristic of birds and population effects. Furthermore, no interspecific differences were detected ( I = 0.999) indicating the morphological changes rather than changes at structural gene loci may have been more important in speciation.     

A comparative study of the Neolithic and Modern human skulls in China

The Neolithic human skulls of this study date from about 6000 years ago (4750–3700 B.C.) and they have been subjected to a cephalometric evaluation by computer and their mandibles and crown have been measured along with the Modern. The data resulting from this measurements have been compared and used in significant tests that led to interesting conclusions. The average Neolithic human ANB angle turned out to be smaller (P<0.05), while their 1-NA (mm) and 1-AP (mm) resulted to be large in comparison with the Modern one. Both Y axis angle and the occlusal plane angle resulted to be smaller for the Neolithic skulls (P<0.01). This results suggest that the Neolithic facial skeleton shows a more evident development: the data of the mandibles are remarkably different in the Neolithic and in the Modern skulls. Indeed, the Neolithic human mandibles are larger: its impacted third molar is 7.5% (the Moderns is 26.5–45.0%; their third molar congenital deficiency is 9.4% (the Moderns is 40.6%). The significance of our results is then discussed.