Rod: Drassodes

Personality traits, such as boldness and/or aggressiveness, have long been accepted to have a profound influence on many aspects of the lives of animals, including foraging. However, little is known about how personality traits shape the use of a particular attack strategy. Ground spiders use either venom or silk attack to immobilize prey. In this study, we tested the hypothesis that behavioral differences among individuals (namely boldness, measured as the time spent exploring a novel environment; and aggressiveness, measured as the number of killed but not consumed prey) drive the use of a particular attack strategy. We used a generalist ground spider, Drassodes lapidosus, and recorded the mode of attack on two types of prey, dangerous and safe. Moreover, we measured the size of the venom gland to test the relationship between the size of venom volume and the personality, as well as the mode of attack. Drassodes individuals showed consistent behavioral differences in the way they attacked prey. Venom attack was significantly related to increased aggressiveness when attacking spider (dangerous) prey and to increased boldness when attacking cricket (safe) prey. Silk attack was more frequently used by shy (for cricket prey) and docile (for spider prey). The volume of venom was not related to the attack strategy. We conclude that personality traits are important drivers of prey-capture behavior in generalist ground spiders.

Heterogeneity of environmental conditions is the crucial factor supporting biodiversity in various habitats, including post-mining sites. The effects of micro-topographic heterogeneity on biodiversity and conservation potential of arthropod communities in post-industrial habitats had not been studied before now. At one of the largest European brown coal spoil heaps, we sampled eight groups of terrestrial arthropods with different life strategies (moths, spiders, ground beetles, ants, orthopteroids, centipedes, millipedes, and woodlice), in successionally young plots (5–18 y), with a heterogeneous wavy surface after heaping, and compared the communities with plots flattened by dozing. A combination of the standardized quantitative sampling, using two different methods, and a paired design of the plot selection enabled a robust analysis. Altogether, we recorded 380 species of the focal arthropods, 15 of them nationally threatened. We revealed the importance of the microtopographic heterogeneity for the formation of the biodiversity of arthropods in their secondary refuges. The communities with higher biodiversity and conservation value were detected in the plots with heterogeneous surfaces; exceptions were ground beetles and millipedes. The surface flattening, often the first step of technical reclamation projects, thus suppress biodiversity of most terrestrial arthropods during the restoration of post-mining sites. Since the communities of both surface types differed, the proportional presence on both surfaces could be more efficient in supporting the local biodiversity. We suggest reducing the surface dozing for the cases with other concerns only, to achieve a proportional representation of both surface types. Such a combination of different restoration approaches would, thus, efficiently support high biodiversity of groups with various needs.

The invertebrates of the Macocha Abyss, Moravian Karst, Czech Republic, were collected in 2007–2008 and 222 species were identified in total. The relative abundance of individual taxa of land snails, harvestmen, pseudoscorpions, spiders, millipedes, centipedes, terrestrial isopods, beetles, and ants was evaluated. The cold-adapted mountain and subterranean species inhabit the bottom and lower part of the abyss, whereas the sun-exposed rocky margins were inhabited by thermophilous species. Macocha harbors several threatened species that are absent or very rare in the surrounding habitats. In the forest landscape, the Macocha Abyss represents a natural habitat with a distinct microclimatic gradient, and is an excellent refuge area for psychrophilous as well as thermophilous species, which significantly contributes to maintenance of landscape biodiversity.

While the majority of the Central European landscape would be covered by forests without human influence, rocky areas form isolated, islet-like, natural, non-forest habitats. The surface of some of these non-forested areas is composed of bare bedrock or products of its erosional breakdown (without a soil layer) such as gravel, sand banks, sand dunes, scree slopes and rock outcrop habitats. These habitats harbour specialized  spider species that depend on their specific substratum and microclimate (Růžička 2000). Out of these habitats, rock walls (and scree slopes) form one of the most distinct ecological gradients of any terrestrial ecosystem (Larson et al. 1989, Růžička et al. 1995). They provide habitats with extremely warm and cold microclimatic conditions in close proximity. They also belong to habitats almost unknown until now due to the technical and practical problems of sampling.

Sandstones can form extensive systems of rocks, sometimes with a broad spectrum of meso- and microhabitats due to their very dynamic relief. Sandstone rocks are characterised by a marked contrast between forested plateau and bare vertical rock walls (Balatka and Sládek 1984). Upper margins of rocks are dry, vertical rock walls can be sun-exposed, dry and bare, or shady and humid and hence covered by mosses. Spaces with an extremely cold climate can occur in deep gorges. The aim of this study is to evaluate available data on the species composition of spider assemblages in sandstone rocks, including new data about spiders on rock walls in the Bohemian Switzerland (České Švýcarsko) National Park.