Czech Arachnological Society

Rapid urbanisation during the last century caused declines in species diversity. Cities encompass only a limited number of highly fragmented natural habitats and thus trees remain an important key factor for survival of local invertebrates. In 2021, we surveyed spider and beetle assemblages inhabiting trees in Pilsen city (Czech Republic). We selected 18 deciduous trees in the surroundings of the city centre and sampled bark species using corrugated cardboard bands, and crown species using a sweep net. The recorded species were evaluated using their functional traits such as habitat and humidity preferences, body size, and feeding guilds – i.e., the methods of spiders’ feeding strategies. Altogether, we recorded 35 spider species/295 individuals, and 43 beetle species/265 individuals. We observed significant differences between the number of species and individuals inhabiting bark and tree crowns. Spiders tended to inhabit bark, while beetles inhabited tree crowns. The trees frequently contained species with different functional traits and with opposite requirements.

Jezero Milada vzniklo na místě bývalého hnědouhelného lomu Chabařovice u Ústí n. L. zatopením zbytkové jámy, které bylo dokončeno v roce 2011.

Současné výzkumy naznačují, že antropogenně narušené lokality mohou poskytovat stanoviště ohroženým a vzácným druhům, jimž v současné okolní kulturní krajině jejich původní stanoviště postupně mizí.

Cílem práce bylo zhodnotit faunu pavouků po kvalitativní i kvantitativní stránce a popsat její odlišnosti ve vztahu k odlišným vlastnostem břehového prostředí a posoudit jeho ochranářskou hodnotu v souvislosti s výskytem ohrožených druhů pavouků.

Bylo zjištěno, že v průběhu sukcese došlo k rozrůznění původně vysoce homogenního kamenitého prostředí, které vzniklo nasypáním kamení na břehy jezera při jeho vytváření. Ukázalo se, že v diverzitě pavouků hraje roli výskyt vegetace, ale i kamenité břehy bez vegetace hostily specifické druhy, čímž přispěly k celkové diverzitě pavouků. Z nalezených 91 druhů pavouků bylo 18 zapsáno v Červeném seznamu. Nejvýznamnějším a zcela nečekaným nálezem byl kriticky ohrožený druh Clubiona juvenis, jenž byl nalezen v rákosu a orobinci.

The eresid spider genus Loureedia (Miller et al., 2012) was described a decade ago, despite its type species being described in the mid-19th century, which illuminates the difficulties in obtaining specimens. The genus was initially described as monotypic. Ever since, four other species have been assigned to Loureedia, including three newly discovered ones. Primarily due to the extravagant appearance of the males, stories about the discovery of species of Loureedia have been the subject of relatively wide media coverage over the years, leading to numerous new populations and putative undescribed species being documented by naturalists and citizen scientists. These species, although bearing distinct differences in their coloration patterns, typically vary only slightly in the structure of their copulatory organs, the primary traits used in spider systematics. This highlights an important taxonomic problem: while it is easy to diagnose the genus or recognize the species that belong to it, it is challenging to differentiate the species from one another, particularly when using only a single line of evidence. In this paper, we have tackled this issue using an integrative approach, i.e., a combination of molecular markers (the mitochondrial COI) and traditional morphological characters. The effects of different observational angles on the perceived shape of the conductor are discussed. Except for one species, we obtained DNA data of all members of the genus. Based on these data, the first phylogeny for Loureedia is presented, and two North African species, Loureedia maroccana (Gál et al., 2017) and Loureedia jerbae (El-Hennawy, 2005), are revalidated from synonymy. The distribution records of all described species are mapped.