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Dive into the research topics where Jaroslav Holuša is active.

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Featured researches published by Jaroslav Holuša.


Central European Journal of Biology | 2009

Pathogens of the spruce bark beetles Ips typographus and Ips duplicatus.

Jaroslav Holuša; J. Weiser; Zdenek Zizka

Pathogens of two important bark beetles, Ips typographus and Ips duplicatus, both in outbreaks connected with infestation of spruces by the fungus Armillaria ostoyae, were compared at four localities in the eastern Czech Republic. Low infestations of Chytridiopsis typographi, Nosema typographi, Menzbieria chalcographi, and Gregarina typographi were detected in I. typographus. In I. duplicatus, only C. typographi and G. typographi were found and with low infection levels. The microsporidium, Larssoniella duplicati, was not detected in I. typographus, but was detected in I. duplicatus at all localities in almost 80% of the samples (a sample consisted of 40–50 beetles collected at one locality in one period) and often with a very high infection level (up to 57% of the beetles infected in a sample). The infection level of L. duplicati did not differ between generations of I. duplicatus. I. duplicatus overwinters mainly in the adult stage, and no decrease in the number of infected overwintering I. duplicatus was observed. The relatively constant infection level of L. duplicati suggests that transmission is unlikely to be horizontal via oral ingestion.


Central European Journal of Biology | 2011

Biology of Tetrix bolivari (Orthoptera: Tetrigidae)

Petr Kočárek; Jaroslav Holuša; Šárka Grucmanová; David Musiolek

The ecological requirements and biology of the Tetrigidae are almost unknown. The aim of the present work is to contribute to the knowledge of Tetrix bolivari, one of the least studied species of European Tetrigidae, by investigating its seasonal and daily activity, food biology, and vibratory communication. Adults of T. bolivari were found from March to September, with the greatest number of detections occurring between May and August. Based on the study of the daily activity patterns, most activities were positively correlated with temperature and negatively correlated with relative humidity. Detritus and mosses were the main components of the diet, with the most frequently consumed mosses being Bryum caespiticium and Bryum argenteum. Substrate-borne vibrational signals used in communication of T. bolivari are described here in detail for the first time. We distinguished four structural types of vibrational signals produced by males, including the signal produced by wing tremulation.


Mycologia | 2012

Liberomyces gen. nov. with two new species of endophytic coelomycetes from broadleaf trees

Sylvie Pažoutová; Petr Šrůtka; Jaroslav Holuša; Milada Chudíčková; Alena Kubátová; Miroslav Kolařík

During a study of endophytic and saprotrophic fungi in the sapwood and phloem of broadleaf trees (Salix alba, Quercus robur, Ulmus laevis, Alnus glutinosa, Betula pendula) fungi belonging to an anamorphic coelomycetous genus not attributable to a described taxon were detected and isolated in pure culture. The new genus, Liberomyces, with two species, L. saliciphilus and L. macrosporus, is described. Both species have subglobose conidiomata containing holoblastic sympodial conidiogenous cells. The conidiomata dehisce irregularly or by ostiole and secrete a slimy suspension of conidia. The conidia are hyaline, narrowly allantoid with a typically curved distal end. In L. macrosporus simultaneous production of synanamorph with thin filamentous conidia was observed occasionally. The genus has no known teleomorph. Related sequences in the public databases belong to endophytes of angiosperms. Phylogenetic analysis revealed a position close to the Xylariales (Sordariomycetes), but family and order affiliation remained unclear.


European Journal of Forest Research | 2006

Impact of defoliation caused by the sawfly Cephalcia lariciphila (Hymenoptera: Pamphilidae) on radial growth of larch (Larix decidua Mill.)

Monika Vejpustková; Jaroslav Holuša

The period between 2000 and 2002 repeated outbreaks of the web spinning sawfly Cephalcia lariciphila (Wachtl 1898) around the village of Větrný Jeníkov, Czech Republic. The impact of defoliation, caused by C. lariciphila feeding, on tree-ring formation of European larch (Larix decidua Mill.) was studied using dendrochronological methods. Heavy defoliation resulted in much less growth in the years of insect attack, the average incremental loss being 67% for the 2000–2002 period. Also, defoliation resulted in the formation of latewood with fewer cells and reduced cell-wall thickness.


Journal of Applied Entomology | 2013

Pathogens of Ips amitinus: new species and comparison with Ips typographus

Karolina Lukášová; Jaroslav Holuša; Marek Turčáni

Ips amitinus and I. typographus are two serious pests of spruce in Europe, have similar bionomics and are likely to occur and meet on the same host trees. We therefore hypothesized that the two species support similar levels of similar pathogens. To test this hypothesis, we collected mature beetles from three trap trees at each of eight study sites and determined beetle numbers and pathogen infection levels. In total, 938 mature I. amitinus beetles and 3435 of I. typographus were dissected; five pathogens, as well as intestinal nematodes and endoparasitoids, were detected. The neogregarine Mattesia schwenkei is reported here for the first time as a new pathogen in 9.4% of I. amitinus individuals at one site. Average infection levels of most pathogens (Chytridiopsis typographi, Gregarina typographi, Mattesia schwenkei and parasitoids) were significantly higher in I. typographus than in I. amitinus. Metschnikowia typographi was confirmed only in Ips amitinus, while the microsporidium of Nosema typographi occurred only in I. typographus. Within‐season increases in G. typographi infection levels were documented in Ips amitinus.


Mycological Progress | 2010

The phylogenetic position of Obolarina dryophila (Xylariales)

Sylvie Pažoutová; Petr Šrůtka; Jaroslav Holuša; Milada Chudíčková; Miroslav Kolařík

The inconspicuous inner-bark parasite Obolarina dryophila is reported from wood of Quercus petraea and as an endophyte of Salix alba. In addition, viable ascospores of O. dryophila have been found in the gut of the oak bark weevil Gasterocercus depressirostris, suggesting a possible dissemination mechanism for the fungus. A phylogenetic analysis based on three genes (nrDNA, actin, β-tubulin) placed Obolarina inside the genus Biscogniauxia as a close relative of the oak pathogens B. atropunctata and B. mediterranea.


Zootaxa | 2013

Annotated checklist of the grasshoppers and crickets (Orthoptera) of the Czech Republic

Jaroslav Holuša; Petr Kočárek; Robert Vlk; Pavel Marhoul

A checklist is presented of the Orthoptera of the Czech Republic. Based on the critical revision of published data and previous lists of species, which often contained only general or questionable data and which often inaccurately cited each other, we found 96 species of Orthoptera belonging to the fauna of the Czech Republic. We emphasize those changes that are based on comparison with previous checklists. We provide information on missing, unclear, and extinct species and on newly detected species, and we confirm the status of species that have been missing for a long time (Leptophyes boscii, Polysarcus denticauda, Ruspolia nitidula, Eumodicogryllus bordigalensis, Tetrix bolivari, Mecostethus parapleurus). We also note those species for which only several individuals have been detected (Pteronemobius heydenii) or those survived only at a single locality (Platycleis montana, Aiolopus thalassinus, Dociostaurus brevicollis, Omocestus petraeus) or at two localities (Poecilimon intermedius, Platycleis veyseli, Pseudopodisma nagyi). Phaneroptera nana is recorded as new for Bohemia.


Journal of Insect Conservation | 2012

Grasshoppers and bushcrickets regionally extinct in the Czech Republic: consequence of the disappearance of habitats scattered on the edge of their ranges

Jaroslav Holuša

According to the International Union for the Conservation of Nature, taxa extinct within a region but extant in other parts of the world should be classified as Regionally Extinct (RE). A taxon is designated RE when there is no reasonable doubt that the last individual capable of reproduction within a region has died or disappeared. A taxon can also be designated RE if it previously but no longer visited a particular region. The species Arcypterafusca, Arcyptera microptera, Celesvariabilis, Gampsocleis glabra, Locusta migratoria, Oedaleusdecorus, and Stenobothrusrubicundulus had previously been found in only a small number of localities in the Czech Republic. We studied localities in the Czech Republic where they had been been previously reported but where their occurences had not been recently confirmed; the last specimens were observed in the 1940, 1960, or 1970s. All these species occurred at Czech localities representing borderline areas for such sub-Mediterranean and mountainous (Carpathian) species. The localities therefore had not offered optimal conditions for these insects, and the suitable biotopes were also scattered and isolated from each other. In most cases, these biotopes had disappeared due to change in management (either to natural or artificial forestation). Although certain of these species are excellent flyers (especially O. decorus), the known recent localities are separated by hundreds of kilometers. Based on our failure to find these species after extensive attempts, we conclude that discussed species should be considered regionally extinct in the Czech Republic. These species are of particularly vulnerable vegetation structures. The loss of these species indicate urgency for assessing status of co-occuring taxa.


Journal of Applied Entomology | 2013

Pathogens of the bark beetle Ips cembrae: microsporidia and gregarines also known from other Ips species

Jaroslav Holuša; Karolina Lukášová; Rudolf Wegensteiner; W. Grodzki; Milan Pernek; J. Weiser

The objective of the current study was to identify pathogens of the large larch bark beetle, Ips cembrae, which is a secondary pest that has produced several local outbreaks across Europe in recent years. Beetles were collected from pheromone traps, trap trees and emergence traps (Larix decidua) during 2007 to 2011 at 10 study sites in central Europe. A total of 3379 mature and callow beetles were examined with a light microscope, and only two microsporidian pathogens [Chytridiopsis typographi and a diplokaryotic microsporidium (probably Nosema sp.)] and two gregarines (Gregarina typographi and Mattesia schwenkei) were found. Within the I. cembrae populations, the infection rate for C. typographi ranged from 2 to 58%. Nosema sp. occurred in only two beetles in 2007 (at two study sites). G. typographi was recorded only in Austria and Croatia and only in 1–2% of the beetles in those countries. Mattesia schwenkei was observed solely in Croatia in 0.6% of the beetles in that country. Only one fungal pathogen in the genus Fusarium was found and only in two mature beetles (0.7%) in 2010. The pathogen species found during our study of I. cembrae were very similar to the pathogens previously identified for Ips typographus. No species‐specific pathogen was detected.


Biologia | 2010

Chemical properties of forest soils as affected by nests of Myrmica ruginodis (Formicidae)

Adam Véle; Jan Frouz; Jaroslav Holuša; Jiří Kalčík

Chemical properties (total and available P concentration; oxidizable C concentration; available K, Na, and Ca concentration; and pH) were quantified for 33 nests of the ant Myrmica ruginodis and in surrounding soil in young spruce forest stands. All properties, except total P, were significantly higher in the nests than in the surrounding soil. Total P was not higher in nests than in surrounding soil across all nests because nests had higher total P than surrounding soil if the soil contained low concentrations of total P but nests had lower total P than surrounding soil if the soil contained high concentrations of total P. The effect of nests on total P in the surrounding soil corresponded with effects of nests on oxidizable carbon (an indicator of organic matter) in the surrounding soil (concentrations of oxidizable carbon and total P were closely correlated). Available P concentrations were much higher in nests than in surrounding soil. Overall, the results indicated that two main processes explain the chemical changes of soil in the ant nests: (i) mixing due to excavation of deeper soil layers and (ii) deposition of excreta and food residues. The effect of soil mixing (whereby ants transport mineral soil from deeper layers to layers near the surface) is more pronounced in soils with high organic content near the surface because mixing increases the proportion of mineral soil in the nest while decreasing the proportion of organic matter and the concentration of total P.

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Karolina Lukášová

Czech University of Life Sciences Prague

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Tomáš Hlásny

Czech University of Life Sciences Prague

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Adam Véle

Czech University of Life Sciences Prague

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Jakub Horák

Czech University of Life Sciences Prague

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Jan Lubojacký

Czech University of Life Sciences Prague

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J. Weiser

Czech University of Life Sciences Prague

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Jiří Trombik

Czech University of Life Sciences Prague

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