Milan Řezáč

Phylogeny of entelegyne spiders: Affinities of the family Penestomidae (NEW RANK), generic phylogeny of Eresidae, and asymmetric rates of change in spinning organ evolution (Araneae, Araneoidea, Entelegynae)

Penestomine spiders were first described from females only and placed in the family Eresidae. Discovery of the male decades later brought surprises, especially in the morphology of the male pedipalp, which features (among other things) a retrolateral tibial apophysis (RTA). The presence of an RTA is synapomorphic for a large clade of spiders exclusive of Eresidae. A molecular data matrix based on four loci was constructed to test two alternative hypotheses: (1) penestomines are eresids and the RTA is convergent, or (2) penestomines belong within the RTA clade. Taxon sampling concentrated on the Eresidae and the RTA clade, especially outside of the Dionycha and Lycosoidea. Evolution of the cribellum, conventionally characterized as a primitive araneomorph spinning organ lost multiple times, is explored. Parsimony optimization indicates repeated appearances of the cribellum. Exploration of asymmetric rates of loss and gain in both a likelihood framework and using a Sankoff matrix under parsimony reveals that cribellum homology is supported when losses are two times more likely than gains. We suggest that when complicated characters appear (under parsimony optimization) to evolve multiple times, investigators should consider alternative reconstructions featuring a relatively high rate of loss. Evolution of other morphological characters is also investigated. The results imply revised circumscription of some RTA-clade families, including Agelenidae, Amaurobiidae, Cybaeidae, Dictynidae and Hahniidae. Some nomenclatural changes are formally proposed here; others await further investigation. The family Penestomidae (NEW RANK) is established. Tamgrinia, not Neoramia, is the cribellate sister clade of the ecribellate Agelenidae. Tamgrinia and the subfamily Coelotinae are transferred from the family Amaurobiidae to the family Agelenidae. Zanomys and its relatives are not coelotines but belong to a clade tentatively identified as Macrobuninae.

Evolution of the karyotype and sex chromosome systems in basal clades of araneomorph spiders (Araneae: Araneomorphae).

Concepts of spider karyotype evolution are based mostly on advanced and most diversified clade, the entelegyne lineage of araneomorph spiders. Hence the typical spider karyotype is supposed to consist exclusively of acrocentric chromosomes including the multiple X chromosomes. However, our data show considerable diversity of chromosome morphology and sex chromosome systems in basal clades of araneomorphs. Karyotypes of basal araneomorphs consist of holocentric (superfamily Dysderoidea) or normal chromosomes with localized centromere. In males of basal araneomorphs the prophase of first meiotic division includes a long diffuse stage. Multiple X chromosomes are less common in basal clades. The sex chromosome system of many families includes a Y chromosome or nucleolus organizer region that occurs rarely in the entelegyne spiders. A derived X1X2Y system with an achiasmatic sex-chromosome pairing during meiosis was found in the families Drymusidae, Hypochilidae, Filistatidae, Sicariidae, and Pholcidae. This suggests a monophyletic origin of the families. In some lineages the X1X2Y system converted into an X0 system, as found in some pholcids, or into an XY system, which is typical for the family Diguetidae. The remarkable karyotype and sex chromosome system diversity allows us to distinguish four evolutionary lineages of basal araneomorphs and hypothesize about the ancestral karyotype of araneomorphs.

The negative effect of some selective insecticides on the functional response of a potential biological control agent, the spider Philodromus cespitum.

The impact of five selective insecticides on the functional response of a potential biological control agent, the spider Philodromus cespitum (Walckenaer) (Araneae: Philodromidae), was studied in the laboratory. This spider is the most abundant beneficial arthropod on trees in commercial orchards in central Europe. We expected that selective insecticides applied at the recommended doses would have no effect or a negligible effect on the spiders’ performance. Our results showed that the mortality of spiders resulting from residual uptake of the chemicals differed among insecticides. Dimilin, NeemAzal, Mospilan, and Integro caused mortality of less than 10%, while SpinTor caused mortality of 17%. All five preparations can be considered harmless in terms of mortality in comparison with Decis, which caused 80% mortality. Exposure to residues of NeemAzal, SpinTor, and Dimilin resulted in a significantly lower predation rate than the control. The lowest predation rate was observed in spiders treated with SpinTor. These results imply that the natural pest control provided by P. cespitum spiders can be weakened by the application of SpinTor, NeemAzal, and Dimilin. On the other hand, the functional response was not significantly affected by the application of Integro and Mospilan. Therefore, these two insecticides are recommended for use in the integrated pest management (IPM) of orchards.

The Spider Genus Dysdera (Araneae, Dysderidae) In Central Europe: Revision And Natural History

Abstract Nine species of the genus Dysdera were found to occur in central Europe: D. adriatica Kulczyński 1897, D. crocata Koch 1838, D. dubrovninnii Deeleman-Reinhold 1988, D. erythrina (Walckenaer 1802), D. ninnii Canestrini 1868, D. hungarica Kulczyński 1897, D. lantosquensis Simon 1882, D. longirostris Doblika 1853, and D. taurica Charitonov 1956. Two species, D. dubrovninnii and D. lantosquensis, are newly recorded from central Europe. The original description of D. hombergi (Scopoli 1763), the name used for a common species of the genus Harpactea, probably refers to D. ninnii. We retain the name D. ninnii as a nomen protectum. Dysdera hamulata Kulczyński 1897 appears to be a junior synonym of D. maurusia Thorell 1873. This North African species probably does not occur in central Europe, and a previous record from Slovakia is probably based on mislabeled material. A review of all species of Dysdera named from outside the Palearctic region demonstrated that D. australiensis Rainbow 1900 and D. magna Keyserling 1877 are junior synonyms of D. crocata, and that D. bicolor Tatzanovski 1874 and D. solers Walckenaer 1837 are erroneously placed in the genus Dysdera; the former is likely to be an oonopid and the latter a caponiid. In central Europe, Dysdera spiders prefer xerothermic forests, particularly sites enriched by calcium. All species probably have biennal life-cycles. The karyotype of males of seven species were examined, and diploid chromosome numbers were found to be extraordinarily variable, ranging from 9 (D. crocata) to 40 (D. longirostris). Karyotypes consist of holocentric chromosomes.

Evidence for woodlice‐specialization in Dysdera spiders: behavioural versus developmental approaches

Abstract The dietary specialization in a woodlouse‐eating spider Dysdera hungarica Kulczyñski (Araneae: Dysderidae) is studied using two types of laboratory experiments. In the first experiment, the rate of development of spiderlings reared on one of three diets: pure woodlice [composed of two species Oniscus asellus Linnaeus and Armadillidium vulgare (Latreille)]; pure flies (Drosophila melanogaster Meigen); and a mixed woodlouse‐fly diet, is studied. Spiders develop significantly faster on the woodlice‐containing diets (i.e. pure woodlice and mixed diet) than on the fly diet. In the second experiment, the prey‐choice for two woodlice species (O. asellus and A. vulgare) and a fly (D. melanogaster) is investigated. Dysdera hungarica spiders capture significantly more often flies than woodlice. These contrasting results reveal the different value of developmental and behavioural experiments. The dietary studies are assumed to provide better evidence of specialization than behavioural experiments, which might be misleading due to unnatural conditions. It is concluded that D. hungarica is a metabolically adapted woodlice specialist. The present study thus provides the first evidence of nutritional specialization on woodlice.

Taxonomic review and phylogenetic analysis of central European Eresus species (Araneae: Eresidae)

Ladybird spiders (Eresus spp.) have attracted scientific interest since the 18th century, but taxonomical knowledge of the genus is unsatisfactory. Early classification based on colour and size variation divided European Eresus into numerous species. These were later lumped into one predominant morphospecies, Eresus niger/E. cinnaberinus, which could be found from Portugal to Central Asia. Here, we perform a major revision of Eresus from northern and central Europe using morphological, phenological, habitat, distribution and molecular data. Three species, E. kollari, E. sandaliatus and E. moravicus sp. n. were distinguished. The name E. niger (originally Aranea nigra) cannot be used as the name A. nigra was used for a previous spider species. The name E. cinnaberinus is considered a nomen dubium. The three species differ in size, colour pattern, shape of prosoma and copulatory organs, phenology, and have slightly different habitat requirements. No morphologically intermediate forms were recorded. In contrast to distinct morphology and phenology, the genus is genetically complex. Genetically, the mitochondrial haplotypes of E. sandaliatus and E. moravicus sp. n. are monophyletic, whereas those of E. kollari are paraphyletic. Eastern central European E. kollari is likely a hybrid lineage between E. sandaliatus and the monophyletic western central European E. kollari. Because eastern and western European E. kollari are morphologically and phenologically indistinguishable, we did not formally split them. However, detailed population‐based research in the future may partition E. kollari into additional species.

Ecology of Arachnida alien to Europe

The ecology of selected species of spiders (Araneae), harvestmen (Opiliones), and the neglected tropical order Schizomida, alien to Europe, is discussed. Their geographic origins and pathways of introduction, by transportation with goods, are similar to other predatory terrestrial arthropods. Occurrence in buildings (synanthropy) is a prerequisite for range expansion in many arachnid species. Thelytokous parthenogenesis facilitated spread of a few spider, harvestman and schizomid species outside their native range. Both prey generalists and specialists (woodlice-eating Dysdera crocata and ant-eating Zodarion rubidum) are among species successfully expanding their range. Alien arachnids include individual species belonging to many different families. We stress the absence of true invasiveness of alien arachnids in Europe. Some unusual adverse effects of alien arachnids were recorded, such as pollution of buildings and clogged car fuel system ventilation tubes. Frequency of painful biting and threat to native biota are low.

Red List of Czech spiders: 3rd edition, adjusted according to evidence-based national conservation priorities

Abstract The knowledge on spiders of the Czech Republic has substantially improved since the second version of the national Red List was published, mainly due to large-scale field records and the establishment of an extensive, searchable electronic database of both retrospective and prospective records. Meanwhile, Central European spiders have undergone substantial changes in abundance and distribution. In this report, an updated Red List is presented and compared with the previous editions from 1992 and 2002, assessing all 879 spider species known to occur in the Czech Republic. For the first time, the abundance, area of occupancy and population trends were calculated for each of the species using the data from the Czech Arachnological Society recording scheme. Twenty-seven species (3% of the total) were classified as Regionally Extinct (RE), 92 (10%) as Critically Endangered, 115 (13%) as Endangered, 155 (18%) as Vulnerable, and 121 (14%) were classified as Least Concern species. Some species listed in the previous version of the Red List were found to live also in non-endangered habitats or to be more common than previously thought, and were thus removed from the list or reclassified to the lower Red List categories. Additionally, several species with dramatically decreasing abundance were identified, among them Ozyptila rauda, Agyneta equestris, Agyneta mollis, Kishidaia conspicua, Clubiona genevensis and Centromerus semiater. The results confirm that spiders are a highly threatened group of arthropods in the Czech Republic, and the updated Red List provides an important foundation for defining conservation priorities

Conservation status of the only representative of infraorder Mygalomorphae (Araneae) in cultivated regions of Central Europe

Purse-web spiders Atypus spp. (Araneae: Atypidae) are the only representatives of the archaic spider infraorder Mygalomorphae in the Central European fauna. These burrow-dwelling spiders are red-listed in all Central European countries. Atypus muralis occurs on relics of continental steppes, Atypus piceus on dry submediterranean grassland and dry herb-rich forest fringes, while Atypus affinis inhabits sparse dwarf dry forests, usually those dominated by oaks. Long-term sustainability of their habitats in the relatively humid Central European climate was maintained by grazing. Since the 1950s, pasturing was terminated across most of Central Europe, which led to immediate overgrowth of pastures by aggressive grasses and woody plants. Grazing was later reinstated in some reserves, but in cases of poorly controlled grazing intensity, footsteps had immediate detrimental effects on the residual populations of purse-web spiders and other invertebrates. Therefore, grazing intensity needs to be regulated, considering its double-edge effects on the biota of xerothermophilic habitats. Nests of European Atypus species have never been found in habitats subject to recent or even regular distribution. Therefore, they may serve as reliable indicators of well preserved xerothermic habitats. Their nests are easy to detect, and the European Atypus spiders can be utilized as model species for monitoring impacts of conservation management. Monitoring population dynamics of Atypus requires establishing permanent study plots of uniform size, documentation of vegetation by phytocenological relevé, counting their density (number of purse-webs found in the plot) and age structure (diameter of purse webs).

Suitability of woodlice prey for generalist and specialist spider predators: a comparative study

1. Predators select a prey according to its energetic and nutritional composition. Generalist predators avoid, whereas specialists often specialise on well‐defended prey. The aim of this study was to find the suitability of woodlice prey for generalist and specialist predators by comparing their handling efficiency.