Jan Hrcek

Jan Hrcek
Biology Centre CAS · Institute of Entomology

PhD

About

56
Publications
12,679
Reads
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1,652
Citations
Introduction
Lab Head, Institute of Entomology, Biology Centre CAS Research Associate, Department of Zoology, University of Oxford http://lab.hrcek.net
Additional affiliations
June 2013 - present
University of Oxford
Position
  • PostDoc Position
February 2008 - November 2012
The Czech Academy of Sciences
Position
  • PhD Student

Publications

Publications (56)
Article
Full-text available
1. In natural communities, multiple host and parasitoid species are linked to form complex networks of trophic and non‐trophic interactions. Understanding how these networks will respond to global warming is of wide relevance for agriculture and conservation. 2. This study synthesises the emerging evidence surrounding host–parasitoid networks in th...
Article
Full-text available
Microbial organisms are ubiquitous in nature, and often form communities closely associated with their host, referred to as the microbiome. The microbiome has strong influence on species interactions, but microbiome studies rarely take interactions between hosts into account, and network interaction studies rarely consider microbiomes. Here, we pro...
Article
Full-text available
Molecular identification is increasingly used to speed up biodiversity surveys and laboratory experiments. However, many groups of organisms cannot be reliably identified using standard databases such as GenBank or BOLD due to lack of sequenced voucher specimens identified by experts. Sometimes a large number of sequences are available, but with to...
Preprint
Climate change is altering the relative timing of species interactions by shifting when species appear in a community and by accelerating developmental rates. However, phenological shifts may be mediated through community contexts, such as intraspecific competition and alternative resource species, which can prolong the otherwise shortened windows...
Article
Full-text available
The analysis of interaction networks across spatial environmental gradients is a powerful approach to investigate the responses of communities to global change. Using a combination of DNA metabarcoding and traditional molecular methods we built bipartite Drosophila – parasitoid food webs from six Australian rainforest sites across gradients spannin...
Article
Climate change is altering the relative timing of species interactions by shifting when species first appear in communities and modifying the duration organisms spend in each developmental stage. However, community contexts, such as intraspecific competition and alternative resource species, can prolong shortened windows of availability and may mit...
Article
Full-text available
Current global changes are reshaping ecological communities and modifying environmental conditions. We need to recognize the combined impact of these biotic and abiotic factors on species interactions, community dynamics and ecosystem functioning. Specifically, the strength of predator prey interactions often depends on the presence of other natura...
Article
Full-text available
Ecological communities are assembled by regional and local processes. These processes select species through their traits, which are tied to species' evolutionary history. A multifaceted approach, encompassing taxonomic, functional and phylogenetic diversity can thus help us to better understand community assembly. We asked what the relative import...
Preprint
Full-text available
Current global changes are reshaping ecological communities and modifying environmental conditions. We need to recognize the combined impact of these biotic and abiotic factors on species interactions, community dynamics and ecosystem functioning. Specifically, the strength of predator-prey interactions often depends on the presence of other natura...
Preprint
Full-text available
While the biogeography of free-living microbial communities is well-studied, community turnover along environmental gradients in host-associated communities is not well understood. In particular, patterns of host-microbiome diversity along elevational gradients remain largely uncharacterized. Because elevational gradients may serve as natural proxi...
Article
A molecular phylogeny of the subfamily Rogadinae is presented for 469 species in 52 genera representing all tribes and subtribes. The data comprise cytochrome c oxidase I sequences (DNA barcodes), together with a broad representation of 28S rDNA D2-D3 expansion region, EF1-α gene and 16S rDNA fragments. To test monophyly, most genera were represent...
Preprint
Full-text available
Ecological communities are composed of a multitude of interacting species, forming complex networks of interactions. Current global changes are altering community composition and we thus need to understand if the mechanisms structuring species interactions are consistent across different species compositions. However, it is challenging to explore w...
Preprint
Full-text available
Molecular identification is increasingly used to speed up biodiversity surveys and laboratory experiments. However, many groups of organisms cannot be reliably identified using standard databases such as GenBank or BOLD due to lack of sequenced voucher specimens identified by experts. Sometimes a large number of sequences are available, but with to...
Article
Full-text available
Global warming is expected to have direct effects on species through their sensitivity to temperature, and also via their biotic interactions, with cascading indirect effects on species, communities, and entire ecosystems. To predict the community-level consequences of global climate change we need to understand the relative roles of both the direc...
Article
Developmental phenotypic plasticity is a widespread phenomenon that allows organisms to produce different adult phenotypes in response to different environments. Investigating the molecular mechanisms underlying plasticity has the potential to reveal the precise changes that lead to the evolution of plasticity as a phenotype. Here, we study wing pl...
Article
Many insects host vertically‐transmitted microbes, which can confer benefits to their hosts but are costly to maintain and regulate. A key feature of these symbioses is variation: for example, symbiont density can vary among host and symbiont genotypes. However, the evolutionary forces maintaining this variation remain unclear. We studied variation...
Preprint
Full-text available
Current global warming trends are expected to have direct effects on species through their sensitivity to temperature, as well as on their biotic interactions, with cascading indirect effects on species, communities, and entire ecosystems. To predict the community-level consequences of global change we need to understand the relative roles of both...
Preprint
Full-text available
A bstract Many insects host vertically-transmitted microbes, which can confer benefits to their hosts but are costly to maintain and regulate. A key feature of these symbioses is variation: for example, symbiont density can vary among host and symbiont genotypes. However, the evolutionary forces maintaining this variation remain unclear. We studied...
Preprint
Full-text available
The analysis of interaction networks across spatial environmental gradients is a powerful approach to investigate the responses of communities to global change. Using a combination of DNA metabarcoding and traditional molecular methods we built bipartite Drosophila-parasitoid food webs from six Australian rainforest sites across gradients spanning...
Article
Many microbial symbionts have multiple phenotypic consequences for their animal hosts. However, the ways in which different symbiont-mediated phenotypes combine to affect fitness are not well understood. We investigated whether there are correlations between different symbiont-mediated phenotypes. We used the symbiont Spiroplasma, a striking exampl...
Article
Full-text available
Invertebrate predators and parasitoids are among the most important natural enemies of insect herbivores. Yet, the strength of natural enemy pressure along an altitudinal gradient and interactions between the groups of natural enemies (such as predation on parasitized prey) are not well known. Various methods are used to reveal the mortality factor...
Article
Full-text available
Questions Species pools are the product of complex ecological and evolutionary mechanisms, operating over a range of spatial scales. Here, we focus on species absent from local sites but with the potential to establish within communities — known as dark diversity. Methods for estimating dark diversity are still being developed and need to be compar...
Presentation
Full-text available
A new Master's study programme in Ecology (www.prf.jcu.cz/ecology) at the University of South Bohemia, will start in September 2019 with 2-years duration, the applications gate is open, deadline for applications is May 16, 2019. The programme extends a successful Quantitative Ecology Module (botanika.prf.jcu.cz/quantecol) lead by Professor Jan Lepš...
Article
1.Environmental stressors can be key drivers of phenotypes, including reproductive strategies and morphological traits. The response to stress may be altered by the presence of microbial associates. For example, in aphids, facultative (secondary) bacterial symbionts can provide protection against natural enemies and stress induced by elevated tempe...
Technical Report
A new 2 year Masters study programme in Ecology, at the University of South Bohemia in České Budějovice, Czech Republic will start in October 2019. The programme is an extension of the successful Quantitative Ecology Module (botanika.prf.jcu.cz/quantecol) lead by Professor Jan Lepš, since 2011. Students will be trained in modern ecology research. T...
Preprint
Full-text available
Interactions within and between species have significant effects on fitness, which are likely to vary across species ranges. However, empirical tests of this are rare, particularly under naturally varying field conditions. We transplanted 19 656 flies of two Australian tropical rainforest fly species ( Drosophila birchii and D. bunnanda ) along an...
Article
Full-text available
Understanding interactions between herbivores and parasitoids is essential for successful biodiversity protection and monitoring and for biological pest control. Morphological identifications employ insect rearing and are complicated by insects’ high diversity and crypsis. DNA barcoding has been successfully used in studies of host–parasitoid inter...
Article
Microbial symbionts commonly protect their hosts from natural enemies, but it is unclear how protective symbionts influence the evolution of host immunity to pathogens. One possibility is that ‘extrinsic’ protection provided by symbionts allows hosts to reduce investment in ‘intrinsic’ immunological resistance mechanisms. We tested this idea using...
Article
Full-text available
Microbial symbionts can play an important role in defending their insect hosts against natural enemies. However, researchers have little idea how the presence of such protective symbionts impacts food web interactions and species diversity. 2. This study investigated the effects of a protective symbiont (Hamiltonella defensa) in pea aphids (Acyrtho...
Article
1.Most animals host communities of symbiotic bacteria. In insects, these symbionts may have particularly intimate interactions with their hosts: many are intracellular and can play important roles in host ecology and evolution, including protection against natural enemies. 2.We investigated how interactions between different species or strains of e...
Article
Animal-associated microbial communities have important effects on host phenotypes. Individuals within and among species differ in the strains and species of microbes that they harbour, but how natural selection shapes the distribution and abundance of symbionts in natural populations is not well understood. Symbionts can be beneficial in certain en...
Data
Figure S1. GS x GP data, shown as a bar graph, with percent sporulation on the y‐axis. Figure S2. GH x GS data, shown as a bar graph, with percent sporulation on the y‐axis. Figure S3. Correlation between symbiont‐mediated protection and the costs of harboring a symbiont across Regiella genotypes. Table S1. Information on the aphid genotypes use...
Article
Full-text available
The microbial symbionts of eukaryotes influence disease resistance in many host-parasite systems. Symbionts show substantial variation in both genotype and phenotype, but it is unclear how natural selection maintains this variation. It is also unknown whether variable symbiont genotypes show specificity with the genotypes of hosts or parasites in n...
Data
Table S1. Experimental field sites. Fig. S1. Differences across replicates in survival of aphids carrying and not carrying symbionts (with binomial standard errors). Fig. S2. Laboratory assays of symbiont conferred protection for strains used in the field experiment. Fig. S3. Endosymbionts are costly under stressful laboratory conditions.
Article
Full-text available
Recent research has shown that the bacterial endosymbionts of insects are abundant and diverse, and that they have numerous different effects on their hosts' biology. Here we explore how insect endosymbionts might affect the structure and dynamics of insect communities. Using the obligate and facultative symbionts of aphids as an example, we find t...
Article
Full-text available
Eukaryotes commonly host communities of heritable symbiotic bacteria, many of which are not essential for their hosts' survival and reproduction. There is laboratory evidence that these facultative symbionts can provide useful adaptations, such as increased resistance to natural enemies. However, we do not know how symbionts affect host fitness whe...
Article
Troporhysipolis gen. nov. with four included species is described and illustrated. The type species, Clinocentrus antefurcalis Granger, 1949, is Afrotropical with unknown biology. We additionally recognise three new species from eastern lowland of Papua New Guinea, T. brenthiaphagus sp. nov., T. markshawi sp. nov. and T. molecularis sp. nov., all t...
Article
Throughout the course of their evolution, plants have acquired a wide range of chemical and mechanical defenses to protect against herbivores. Ehrlich & Raven's coevolutionary theory suggests that this diversification of defensive traits is driven by the strong impact of novel traits on insect herbivores. However, the impact of plant defenses on in...
Article
Full-text available
1.Plant-insect food webs tend to be dominated by interactions resulting from diffuse coevolution between plants and multiple lineages of herbivores rather than by reciprocal coevolution and co-cladogenesis. Plants therefore require defence strategies effective against a broad range of herbivore species. In one extreme, plants could develop a single...
Article
Full-text available
Understanding variation in resource specialization is important for progress on issues that include coevolution, community assembly, ecosystem processes, and the latitudinal gradient of species richness. Herbivorous insects are useful models for studying resource specialization, and the interaction between plants and herbivorous insects is one of t...
Article
Full-text available
Quantitative food webs are valuable tools to detect patterns in community structure and generate hypotheses for experimentation. Quantitative webs of whole communities are usually not feasible to build, and most attention focuses on assemblages of species that interact in similar ways. Hosts and parasitoids are a popular guild for study, and quanti...
Article
Full-text available
A new species of Cystomastacoides van Achterberg, C. asotaphaga Quicke sp. n., is described and illustrated based on a series of specimens reared from caterpillars of the erebid moth Asota plana Walker from Papua New Guinea. Two other new species without biological data are also described, C. nicolepeelerae QuickeandButcher sp. n. also from Papua N...
Article
Full-text available
The processes maintaining the enormous diversity of herbivore-parasitoid food webs depend on parasitism rate and parasitoid host specificity. The two parameters have to be evaluated in concert to make conclusions about the importance of parasitoids as natural enemies and guide biological control. We document parasitism rate and host specificity in...
Article
Full-text available
Microgastrine wasps are among the most species-rich and numerous parasitoids of caterpillars (Lepidoptera). They are often host-specific and thus are extensively used in biological control efforts and figure prominently in trophic webs. However, their extraordinary diversity coupled with the occurrence of many cryptic species produces a significant...
Article
Full-text available
Nine new species of Colastomion Baker are described, illustrated and keyed based on series of specimens reared from caterpillars of crambid moths from lowland Papua New Guinea plus one additional field collected specimen, viz. C. cheesmanae Quicke sp. n., C. crambidiphagus Quicke sp. n., C. gregarius Quicke sp. n., C. maclayi Quicke sp. n., C. mada...
Article
Full-text available
Phylogenetic ecology has identified patterns of diversity in communities that may find explanation in trophic interactions, and yet there have been few attempts to directly relate such patterns among trophic levels. Density-dependent processes involving pests and pathogens, for example, have been invoked to account for plant community phylogenetic...
Article
Full-text available
Vojtechirogas novotnyi gen. nov. & sp. nov., V. heberti sp. nov. and V. wantok sp. nov. reared from Philiris helena (Snellen) (Lepidoptera: Lycaenidae) feeding on Macaranga spp., in northern lowland Papua New Guinea, are described and illustrated. Based on molecular data, on the modified vein 2-SC+R of the hind wing and the inclivous vein r-m of th...
Article
Full-text available
Wolbachia is a genus of bacterial endosymbionts that impacts the breeding systems of their hosts. Wolbachia can confuse the patterns of mitochondrial variation, including DNA barcodes, because it influences the pathways through which mitochondria are inherited. We examined the extent to which these endosymbionts are detected in routine DNA barcodin...
Article
The enormous cytochrome oxidase subunit I (COI) sequence database being assembled from the various DNA barcoding projects as well as from independent phylogenetic studies constitutes an almost unprecedented amount of data for molecular systematics, in addition to its role in species identification and discovery. As part of a study of the potential...
Article
Full-text available
Classical niche theory explains the coexistence of species through their exploitation of different resources. Assemblages of herbivores coexisting on a particular plant species are thus expected to be dominated by species from host-specific guilds with narrow, coexistence-facilitating niches rather than by species from generalist guilds. Exactly th...
Article
Previously, host-parasitoid links have been unveiled almost exclusively by time-intensive rearing, while molecular methods were used only in simple agricultural host-parasitoid systems in the form of species-specific primers. Here, we present a general method for the molecular detection of these links applied to a complex caterpillar-parasitoid foo...
Article
Full-text available
The distribution of Lopinga achine (Lepidoptera Nymphalidae, Satyrinae) in the Czech Republic has declined from thirty grid squares before 1950 to just one extant population, restricted to a single area of deciduous woodland. A review of historical sites shows that this species used to occur in various types of deciduous woodland with a relatively...

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Project
Influence of elevation can be tested for host parasitoid interactions, where changes in interactions may help better understand to observed variations, moreover, it can help to resolve patterns of latitudinal parasitoid diversity. The same question can be asked at the level of entire host-parasitoid networks: How does structure of tropical caterpillar – parasitoid food webs change with altitude?