1. elektronické vydání 1 online zdroj (260 stran)
Kniha doplňuje předchozí tři díly o další regresní modely, konkrétně parametrické i semiparametrické modely pro analýzu času do události, regresní stromy a vybrané mnohorozměrné metody, jako je PCA nebo LDA. Text knihy je praktickou příručkou analýzy dat v prostředí R. Je sestaven z 20 vzorově vyřešených a okomentovaných příkladů, které mají za cíl nejen představit danou metodu, ale také poukázat na problémy, na které může čtenář narazit při analýze vlastních dat. Text je psán jednoduchým jazykem, srozumitelným pro čtenáře s biologickým vzděláním. Kniha je určena především studentům a kolegům z biologických oborů, ale také veterinárních, lékařských a farmaceutických oborů.
1. vydání vii, 252 stran : ilustrace ; 24 cm
Příručka a vysokoškolská učebnice, která se zaměřuje na metody analýzy biologických dat, zejména na analýzu času do události. Určeno studujícím i odborníkům v praxi.
- MeSH
- analýza dat MeSH
- biologické modely MeSH
- biologie MeSH
- čas MeSH
- Publikační typ
- příručky MeSH
- Konspekt
- Biologické vědy
- Učební osnovy. Vyučovací předměty. Učebnice
- NLK Obory
- biologie
- statistika, zdravotnická statistika
- přírodní vědy
- NLK Publikační typ
- učebnice vysokých škol
Spiders are a highly diversified group of arthropods and play an important role in terrestrial ecosystems as ubiquitous predators, which makes them a suitable group to test a variety of eco-evolutionary hypotheses. For this purpose, knowledge of a diverse range of species traits is required. Until now, data on spider traits have been scattered across thousands of publications produced for over two centuries and written in diverse languages. To facilitate access to such data, we developed an online database for archiving and accessing spider traits at a global scale. The database has been designed to accommodate a great variety of traits (e.g. ecological, behavioural and morphological) measured at individual, species or higher taxonomic levels. Records are accompanied by extensive metadata (e.g. location and method). The database is curated by an expert team, regularly updated and open to any user. A future goal of the growing database is to include all published and unpublished data on spider traits provided by experts worldwide and to facilitate broad cross-taxon assays in functional ecology and comparative biology. Database URL:https://spidertraits.sci.muni.cz/.
- MeSH
- členovci * MeSH
- databáze faktografické MeSH
- ekosystém MeSH
- fenotyp MeSH
- pavouci * genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Interactions among endosymbiotic bacteria inside their eukaryotic hosts are poorly understood, particularly in mites. The mite Tyrophagus putrescentiae is a common, medically important generalist species that has many intracellular and gut bacterial symbionts. In the experiments, we examined bacterial abundances and composition in mite populations obtained by controlled mixing of stock mite populations that differed in the presence/absence of the major intracellular bacteria Wolbachia and Cardinium. Changes in microbial communities were characterized using 16S ribosomal RNA high-throughput sequencing (pooled mite individuals) and quantitative PCR for key microbial taxa (individual mites). Mite fitness was estimated as a parameter of population growth. We detected that in mixed mite populations, Cardinium and Wolbachia can co-occur in the same mite individual. The presence of Cardinium was negatively correlated with the presence of Wolbachia and Bartonella, while the Bartonella and Wolbachia were positively correlated in individual level samples. Since mixed populations had lower abundances of Wolbachia, while the abundance of Cardinium did not change, we suggest that the presence of Cardinium inhibits the growth of Wolbachia. The mixed mite populations had lower population growth than parental populations. The possible effect of symbionts on the fitness of mixed population is discussed.
- MeSH
- Acaridae * MeSH
- Bacteroidetes genetika MeSH
- lidé MeSH
- mikrobiota * MeSH
- roztoči * MeSH
- symbióza MeSH
- Wolbachia * genetika MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
House dust mites inhabit bed mattresses contaminating them with allergens. A strong temperature/moisture gradient exists in mattresses when it is used by humans daily. Here, we studied migration patterns of the mite Dermatophagoides farinae in continuous and time-discontinuous temperature gradients consisting of five sectors with 19-23, 23-28, 28-32, 32-36 and 36-41 °C, containing dye-labeled diets as an indicator of mite presence and feeding. The mites migrated through the sectors and fed on the labeled diets or stayed unfed. The numbers of mites with the same coloration in their guts and the numbers of unfed mites in the sectors were recorded. Unfed mites provided information on short-term temperature preferences. Apart from a control trial, two experiments were performed: (i) a constant 19-41 °C gradient for 24 h, and (ii) alternating cycles of the same temperature gradient (19-41 °C, 8 h) and room temperature (16 h) for 5 days to model the typical daily occupancy of bed by humans. In both experiments, fed mites preferred a sector with 32-36 °C, suggesting that in mattresses, house dust mites prefer to stay as close as possible to the resting human, thus maximizing allergen exposure. However, the number of unfed mites decreased with increased temperatures in the gradient. Experiment (ii) showed that the fed mites remained at the same optimal distance from the heat source, suggesting that they stay at the upper surface of the regularly used mattress, even when human was temporarily absent during the day. Unfed mites apparently hide deeper in mattresses as suggested by their avoidance of increased temperatures.
In Batesian mimicry, the mimic gains protection from predators by imitating a noxious model. Some myrmecomorphic species use ants as models as ants have strong defensive capabilities. Ants are highly mobile models, and besides colour, shape, and size, mimics also imitate their movement. Yet, former studies focused mainly on static traits. Here, I tested the hypothesis that artificially increased speed of movement reduces the probability of the mimic being identified. First, images of 14 myrmecomorphic spider species and their models were used for humans to rank their mimetic accuracy. Humans were used as surrogate predators to obtain scores for each mimetic pair. In the second experiment, the effect of movement playback speed on the probability of identification was investigated, again using humans. Videos of mimics were played at different speeds, and the identification probability was recorded. While ants were correctly identified at any playback speed, the identification of myrmecomorphic spiders declined with increasing playback speed. In other words, the latency to correct identification increased with playback speed. Overall, mimics with higher accuracy scores were more difficult to identify while moving. The natural speed of movement of accurate mimics was similar to that of inaccurate ones. Movement is thus an important trait for myrmecomorphic species.
In culture, the house dust mite, Dermatophagoides pteronyssinus, shows different growth patterns, but the composition and changes in the associated microbial community during mite culture growth are poorly known. In this study, we analyzed temporal changes in microbial communities including 'internal' communities (inside mites, ingested) and 'environmental' communities (from culture environment). Microbial community structure was correlated with guanine content (a nitrogenous waste product of mites) and mite population density. Both internal and environmental microbial communities were remarkably consistent between biological replicates from the same culture age group and were composed of relatively few dominant taxa-11 bacterial and 3 fungal operational taxonomic units (OTUs). Significant changes over time in microbial community structure in the bulk culture environment and in internal mite samples were observed. The yeast, Saccharomyces cerevisiae, a main component of the mite diet, gradually disappeared during mite culture growth and was replaced by fungi from the genera Aspergillus and Candida in both 'internal' and 'environmental' samples. In environmental samples, bacteria from the genus Lactobacillus and S. cerevisiae were negatively correlated, and Aspergillus and Candida positively correlated, with guanine content. The relative abundance of bacteria from the genus Kocuria increased with mite density but declined with increasing guanine content. The relative abundance of bacteria from the genus Virgibacillus was negatively correlated with mite density in 'internal' samples. Gram-positive bacteria dominated bacterial microbiomes at all time points in our experiments, indicating a more limited possibility for vaccine contamination by bacterial endotoxins (heat-stable lipopolysaccharides produced mostly by Gram-negative bacteria) in our experimental cultures.
- MeSH
- Bacteria genetika MeSH
- Dermatophagoides pteronyssinus * MeSH
- houby MeSH
- mikrobiota * MeSH
- Saccharomyces cerevisiae MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Modern pest control management systems are based on the support of naturally occurring arthropod predators, as it has been shown that such predators offer an important ecosystem service. However, most naturally occurring arthropod predators are generalists (euryphagous). Their role in the biological control of specific pests has been recognized but remains poorly studied. Here, we focused on the naturally occurring arthropod predators of psyllids - the main insect pest of pear trees. We investigated the abundance of psyllids and all of their potential enemies in an abandoned pear orchard on a weekly basis from early spring to early summer. In addition, employing polymerase chain reaction diagnostics and specific primers, we investigated the predation rate on psyllids in all predators collected. RESULTS: We found four predatory groups: spiders were the most abundant (60%, N = 756), followed by coccinellid beetles, anthocorid bugs and cantharid beetles. Anthocorids and spiders had the highest predation rates among the predatory groups. Among spiders, >50% of foliage-dwelling spiders (belonging to the genera Philodromus and Clubiona; N = 206) were positive for psyllids and showed a numerical response to the abundance of psyllids. CONCLUSION: We conclude that foliage-dwelling spiders are, of the four groups, the most important natural enemies of psyllids on pear trees during spring in Central Europe, as they outnumber specialized Anthocoris bugs. © 2021 Society of Chemical Industry.
1. elektronické vydání 1 online zdroj (278 stran)
Kniha je zaměřena na regresní modely, konkrétně jednorozměrné zobecněné lineární modely (GLM). Je určena především studentům a kolegům z biologických oborů a vyžaduje pouze základní statistické vzdělání, jakým je např. jednosemestrový kurz biostatistiky. Kniha obsahuje nezbytné minimum statistické teorie, především však řešení 18 reálných příkladů z oblasti biologie. Každý příklad je rozpracován od popisu a stanovení cíle přes vývoj statistického modelu až po závěr. K analýze dat je použit populární a volně dostupný statistický software R. Příklady autoři záměrně vybrali tak, aby upozornili na různé problémy a chyby, které se mohou v průběhu analýzy dat vyskytnout. Zároveň mají čtenáře motivovat, jak o statistických modelech přemýšlet a jak je používat. Řešení příkladů si může čtenář vyzkoušet na datech, jež jsou dodávána spolu s knihou.
Among spiders, taxonomically the most diversified group of terrestrial predators, only a few species are stenophagous and feed on ants. The levels of stenophagy and ant-specialisation vary among such species. To investigate whether stenophagy is only a result of a local specialisation both fundamental and realised trophic niches need to be estimated. Here we investigated trophic niches in three closely-related spider species from the family Gnaphosidae (Callilepis nocturna, C. schuszteri, Nomisia exornata) with different levels of myrmecophagy. Acceptance experiments were used to estimate fundamental trophic niches and molecular methods to estimate realised trophic niches. For the latter two PCR primer sets were used as these can affect the niche breadth estimates. The general invertebrate ZBJ primers were not appropriate for detecting ant DNA as they revealed very few prey types, therefore ant-specific primers were used. The cut-off threshold for erroneous MOTUs was identified as 0.005% of the total number of valid sequences, at individual predator level it was 0.05%. The fundamental trophic niche of Callilepis species included mainly ants, while that of N. exornata included many different prey types. The realised trophic niche in Callilepis species was similar to its fundamental niche but in N. exornata the fundamental niche was wider than realised niche. The results show that Callilepis species are ant-eating (specialised) stenophagous predators, catching mainly Formicinae ants, while N. exornata is an ant-eating euryphagous predator catching mainly Myrmicinae ants.
