A two-year field experiment was conducted to determine whether a conservation biological control strategy could be applied to enhance the biological control of green apple aphids, Aphis spp., in a high-density and scab-resistant apple orchard at the non-bearing stage. The natural occurrence of aphid predators and their impact on aphid populations were evaluated in 2005. The impact of predation on aphid densities was evaluated by comparing a predator exclusion treatment with a control. In 2006, the possibility to enhance predator abundance/performance and aphid biological control with a flowering ground cover was tested: trees were grown either with a flowering ground cover of phacelia, Phacelia tanacetifolia Bentham, and buckwheat, Fagopyrum esculentum Moench, or with a conventional ground cover of mixed Poaceae species. In 2006, it was also determined whether aphid densities differ between Liberty and Topaz, 2 scab-resistant cultivars. Results indicate that the predatory arthropod community was dominated by Coccinellidae, Cecidomyiidae, and various spider species. The ladybird community was dominated by the exotic species Harmonia axyridis Pallas, and the abundance of this species was correlated with aphid density. Naturally occurring predators had little impact on aphid abundance, although the proportion of trees with aphid colonies was greater in the predator exclusion treatment on two consecutive dates in 2005. Ground cover types had no impact on aphid densities. The oviposition response of Cecidomyiidae to aphid density was greater in Liberty trees with flowering ground cover than with the conventional ground cover. Conversely, the response of ladybird adults to aphid density was more important in Topaz trees with the conventional ground cover than with the flowering ground cover. Finally, no difference occurred in aphid abundance between Liberty and Topaz trees. Those results are discussed from a biological control and ecological point of view.
Pitfall traps are widely used for sampling ground-dwelling arthropods. Their sampling efficiency is affected by several factors, e.g. material, size and modification of parts of the trap and sampling design. Pitfall trap sampling is also affected by the accumulation of plant litter in the traps, rain fall and by-catches of small vertebrates, which may cause a bias in the catch by obstructing traps or attracting certain insects. A roof that prevents rain and plant litter entering a trap, prevents dilution of the preservative and escape of arthropods. The main goal of present study was to compare the effect of four types of differently combined funnel and roof pitfall traps on the capture efficiency of epigeal arthropods. We found that a funnel and/or a roof had no effect on spider catches. Total abundance of large carabids and thus the total abundance of ground beetles was lower in funnel pitfall traps without a roof than in other types of traps. However, funnel pitfall traps with roofs collected significantly more carabid beetles, especially individuals of those species that are large or good fliers. We conclude that funnel pitfall traps with roofs have no negative effects on capture efficiency of ground beetles and spiders, therefore application of this sampling technique is strongly recommended.
The aim of this study was to characterize karyotypes of central European spiders of the genera Arctosa, Tricca, and Xerolycosa (Lycosidae) with respect to the diploid chromosome number, chromosome morphology, and sex chromosomes. Karyotype data are reported for eleven species, six of them for the first time. For selected species the pattern in the distributions of the constitutive heterochromatin and the nucleolar organizer regions (NORs) was determined. The silver staining technique for detecting NORs of lycosid spiders was standardized. The male karyotype consisted of 2n = 28 (Arctosa and Tricca) or 2n = 22 (Xerolycosa) acrocentric chromosomes. The sex chromosome system was X1X20 in all species. The sex chromosomes of T. lutetiana and X. nemoralis showed unusual behaviour during late diplotene, namely temporary extension due to decondensation. C-banding technique revealed a small amount of constitutive heterochromatin at the centromeric region of the chromosomes. Two pairs of autosomes bore terminal NORs. Differences in karyotypes among Arctosa species indicate that the evolution of the karyotype in this genus involved autosome translocations and size changes in the sex chromosomes. Based on published results and those recorded in this study it is suggested that the ancestral male karyotype of the superfamily Lycosoidea consisted of 28 acrocentric chromosomes. and Petr DOLEJŠ, Tereza KOŘÍNKOVÁ, Jana MUSILOVÁ, Věra OPATOVÁ, Lenka KUBCOVÁ, Jan BUCHAR, Jiří KRÁL.
Pro rok 2016 se evropským pavoukem roku stal křižák Cyclosa conica. Po morfologické stránce je tento druh nezaměnitelný díky přítomnosti hrbolku na zadním konci hřbetu zadečku. Jeho kolová síť je vybavena vertikálním stabilimentem se zapředenými zbytky kořisti či detritu. Pavouk na kořist číhá uprostřed stabilimenta. Při ohrožení je schopen na síti vibrovat tak, že se pro predátora stane takřka nedetekovatelným., The araneid Cyclosa conica was chosen as European Spider of the Year for 2016. Morphologically the spider is characterised by a single tubercle on the hind part of the dorsal abdomen. Its web carries a vertical stabilimentum with remnants of prey and other detritus. The spider waits for its prey in the middle of the stabilimentum. When disturbed, it vibrates on the web, so it becomes almost undetectable., and Milan Řezáč.
Studovali jsme výskyt pavouků v půdě, v puklinách v hornině, v kamenitých sutích a v jeskyních České republiky, to jest v podzemních biotopech na hloubkovém gradientu od 10 cm do 100 m. Třináct druhů vykazovalo nějaká morfologická přizpůsobení k životu v podzemí. Druhy s výrazně redukovanýma očima jsme našli jak v hlubokých jeskyních, tak i v povrchových biotopech daleko od krasu. Údaje o morfologii a rozšíření ukazují na to, že troglomorfní druhy musely v průběhu zalednění opakovaně migrovat z jeskyní do povrchových biotopů., Using data from the Czech Republic, we studied the distribution of spiders in soils, crevice systems, scree and caves, i.e. subterranean habitats at depths spanning from 10 cm to 100 m. Thirteen species exhibit morphological adaptations to life in subterranean habitats. Advanced troglomorphic characters occur in deep caves as well as in surface habitats far from karst regions. We hypothesize that troglomorphic populations of spiders in Central Europe repeatedly migrated from caves to subsurface and surface habitats during glaciations., and Vlastimil Růžička.
Plachetnatka nákorní (Drapetisca socialis) z čeledi plachetnatkovití (Linyphiidae) je jedním z mála druhů pavouků žijících v České republice, který se dokonale přizpůsobil k životu na kmenech stromů adaptacemi morfologickými (zbarvení, délka končetin) i etologickými. Síť této plachetnatky se skládá pouze z několika horizontálně a vertikálně napnutých vláken., Drapetisca socialis from the family Linyphiidae is a spider species with great morphological (coloration, long legs) and ethological (web reduction) adaptations to life on smooth tree trunks. This spider attaches an unusual reduced web vertically to tree trunks., and Ondřej Machač.
There are 15 members of the Wolf Spiders genus Alopecosa in the Czech Republic, most of which are rare and stenoecious. Although they have been studied for a long time, we do not have much information about their biology and reproduction. Members of this genus show a large variability in courtship and copulatory behaviour., K zajímavým rodům slíďáků náleží rod Alopecosa, na území České republiky známe výskyt 15 druhů rodu. Ačkoli ojedinělé záznamy o biologii a taxonomii rodu máme sice už z 18. stol., jejich studium pokračuje zejména v dnešní době, kdy se do popředí dostává výzkum rozmnožování., and Pavel Just.
Článek shrnuje dosavadní znalosti o pavoucích zimujících v ulitách suchozemských plžů v České republice. Jde o dvě studie - jedna ze zimy 2008/2009 (2 448 prázdných ulit tří druhů suchozemských plžů: suchomilka obecná (Xerolenta obvia), páskovka žíhaná (Cepaea vindobonensis) a hlemýžď zahradní (Helix pomatia)). Druhá studie byla provedena v zimním období 2010/2011 (přes 30 000 ulit, stejné druhy jako v předchozích letech plus druhy: skalnice kýlnatá (Helicigona lapicida) a plamatka lesní (Arianta arbustorum)). Prozatím jsou souhrnně zpracována data z první studie, z druhé jsou v článku zmíněny pouze faunisticky významnější nálezy. Naše zjištění potvrzují nálezy ze zahraničí, že v ulitách přezimuje, často hojně, celá řada druhů pavouků, které považujeme za vzácné. Asi nejvýznamnější druhy jsou: skálovka šestitečná (Phaeocedus braccatus), snovačka pětitečná (Euryopis quinqueguttata), skákavka dvoutečná (Sitticus penicillatus), zápřednice Pennyova (Cheiracanthium pennyi), zápřednice karmínová (Ch. montanum) a další., This article summarises our knowledge of overwintering spiders in land snail shells in the Czech Republic. The results of two studies, based on the survey of more than 32 000 shells of 5 species, confirmed that many spider species considered rare actually overwinter in shells, often in large numbers. The most important records include Phaeocedus braccatus, Euryopis quinqueguttata, Sitticus penicillatus, Cheiracanthium pennyi and Ch. montanum., and Jana Niedobová, Vladimír Hula, Ondřej Košulič.
Šplhalka keřová (Anyphaena accentuata) je jedním z mála evropských zástupců čeledi Anyphaenidae. Jde o středně velkého pavouka s charakteristickou kresbou na hřbetě zadečku. Vyskytuje se na keřích a stromech, kde pátrá po své kořisti. Samci provozují neobvyklé námluvy: svými makadly a prvním párem nohou bubnují na úkryt samice a zároveň vibrují svým zadečkem, čímž vyluzují bzučivý zvuk. Šplhalka keřová se vyskytuje v teplomilných listnatých lesích, především v nižších polohách., The species Anyphaena accentuata, one of the few European representatives of the Anyphaenidae family, occur mainly in deciduous forests, in lowland areas. This medium-size spider with a characteristic colour pattern on the dorsal side of abdomen climbs bush and tree vegetation where it searches for its prey. The males exhibit an unusual mating behaviour. They drum with the pedipalps and the first pair of legs on the female’s retreat, simultaneously vibrating their abdomen, creating a buzzing noise., and Milan Řezáč.