Negative frequency-dependent selection (NFDS) is an evolutionary mechanism suggested to govern host-parasite coevolution and the maintenance of genetic diversity at host resistance loci, such as vertebrate MHC R-genes in plants. Matching-allele interactions hosts parasites that prevent emergence parasite genotypes are universally resistant infective a predicted underpin NFDS. The underlying genetics matching-allele unknown even systems with empirical support for by NFDS, case planktonic...

Abstract Dormancy is a common adaptation in invertebrates to survive harsh conditions. Triggered by environmental cues, populations produce resting eggs that allow them temporally unsuitable D aphnia magna crustacean reproduces cyclical parthenogenesis, alternating between the production of asexual offspring and sexual reproduction diapausing (ephippia). Prior ephippia production, males (necessary ensure fertilization) are produced parthenogenetically. Both parthenogenetic induced factors....

Abstract How a host fights infection depends on an ordered sequence of steps, beginning with attempts to prevent pathogen from establishing infection, through steps that mitigate pathogen's control resources or minimize the damage caused during infection. Yet empirically characterizing genetic basis these remains challenging. Although each step is likely have unique and environmental signature, may therefore respond selection in different ways, events occur earlier process can mask overwhelm...

Daphnia magna is a well-established model species in ecotoxicology, ecology and evolution. Several new genomics tools are presently under development for this species; among them, linkage map first requirement estimating the genetic background of phenotypic traits quantitative trait loci (QTL) studies also very useful assembling genome. It enables comparative between D. pulex, which already exists. Here we describe magna. We generated 214 F2 (intercross) clonal lines as foundation analysis....

Multiple infections of the same host by different strains microparasite species are believed to play a crucial role during evolution parasite virulence. We investigated specificity, relative virulence and dose in determining competitive outcome multiple Daphnia magna-Pasteuria ramosa host-parasite system. found that P. clones (single genotype) were less virulent produced more spores than isolates (possibly containing genotypes). also two similarly differed considerably their within-host...

Although Daphnia is increasingly recognized as a model for ecological genomics and biomedical research, there is, of yet, no high-resolution genetic map the genus. Such would provide an important tool mapping phenotypes assembling genome. Here we estimate genome size magna describe construction SNP array based linkage map. We then test suitability life history behavioural trait mapping. The two parent genotypes used to produce derived from D. populations with without fish predation,...

Abstract Social insect colonies possess a range of defences which protect them against highly virulent parasites and colony collapse. The host–parasite interaction between honey bees ( Apis mellifera ) the mite Varroa destructor is unusual, as bee are relatively poorly defended this parasite. has existed since mid‐20th Century, when switched host to parasitize A. . combination parasite naïve means that, without acaricides, typically die within 3 years infestation. A consequence acaricide use...

SUMMARY Pseudomonas syringae pv. tomato is the causative agent of bacterial speck tomato. The key virulence determinant P. hrp gene cluster, which encodes a type III secretion system. system used by wide variety pathogenic bacteria for transporting proteins from directly into eukaryotic host cell. Hrp pilus, composed HrpA pilin subunits, an indispensable component in syringae. Here we have determined spatial and temporal expression pattern hrpA DC3000 intact leaves, using HrpA-GFP protein...

The pattern of genetic variation within and among populations a species is strongly affected by its phylogeographic history. Analyses based on putatively neutral markers provide data from which past events, such as population expansions colonizations, can be inferred. Drosophila virilis cosmopolitan belonging to the group, where divergence times between different phylads go back early Miocene. We analysed mitochondrial DNA sequence 35 strains covering species' range in order detect...

In many host populations, one of the most striking differences among hosts is their age. While parasite prevalence in relation to age are well known, little known on how impacts ecological and evolutionary dynamics diseases. Using two clones water flea Daphnia magna its bacterial Pasteuria ramosa, we examined at exposure influences within-host competition virulence. We found that multiply-exposed were more susceptible infection suffered higher mortality than singly-exposed hosts. Hosts...

Abstract The Red Queen hypothesis predicts that host–parasite coevolutionary dynamics can select for host resistance through increased genetic diversity, recombination and evolutionary rates. However, in haplodiploid organisms such as the honeybee ( Apis mellifera ), models suggest selective pressure is weaker than diploids. Haplodiploid sex determination, found A. , allow deleterious recessive alleles to persist population diploid with negative effects predominantly expressed haploid sex....

The Drosophila virilis species group offers valuable opportunities for studying the roles of chromosomal re-arrangements and mating signals in speciation. 13 are divided into two subgroups, montana 'phylads'. There is greater differentiation among within phylad both karyotype acoustic than exists members phylad. a divergent which included Here, we analyse phylogeography D. to provide framework understanding divergence populations. We analysed mitochondrial sequences corresponding cytochrome...

Drosophila montana, a species of the virilis group, has distributed around northern hemisphere. Phylogeographic analyses two North American and one Eurasian population this offer good background for studies on extent variation in phenotypic traits between populations as well tracing selection pressures likely to play role character divergence. In present paper, we studied male courtship song, wing genital characters among flies from Colorado (USA), Vancouver (Canada) Oulanka (Finland)...

Abstract Diapause is a feature of the life cycle many invertebrates by which unfavourable environmental conditions can be outlived. The seasonal timing diapause allows organisms to adapt changes in habitat suitability and thus key their fitness. In planktonic crustacean Daphnia, various cues induce production stages that are resistant heat, drought or freezing contain one two embryos developmental arrest. Daphnia keystone species freshwater ecosystems, where it acts as main link between...

SUMMARY Knowing the determinants of geographic ranges parasites is important for understanding their evolutionary ecology, epidemiology and potential to expand range. Here we explore range in peculiar case a parasite species – microsporidian Hamiltosporidium tvaerminnensis that has limited distribution wide-spread host Daphnia magna . We conducted quantitative trait loci (QTLs) analysis with monoclonal F 2 D. populations originating from cross between susceptible northern European genotype...

The evolution of animal genitalia has gained renewed interest because their potential roles during sexual selection and early stages species formation. Although central to understanding the evolutionary process, knowledge genetic basis natural variation in genital morphology is limited a very few species. Using an outbred cross between phylogenetically distinct lines Drosophila montana, we characterized quantitative trait loci (QTLs) affecting size shape distiphallus, prominent part male...

Abstract The parasitic mite Varroa destructor devastates honey bee ( Apis mellifera ) colonies around the world. Entering a brood cell shortly before capping, mother feeds on larvae. hormones 20‐hydroxyecdysone (20E) and juvenile hormone (JH), acquired from host, have been considered to play key role in initiating Varroa's reproductive cycle. This study focuses differential expression of genes involved biosynthesis JH ecdysone at six time points during first 30 hr after capping both drone...

Zooplankton can display complex habitat selection behaviours that influence the way they interact with their environments. Some species, although primarily pelagic, exploit sediment-borne particles as a food source or use sediments refuge from pelagic predation. However, this strategy may increase exposure to other risks such benthic predation and infection parasite transmission stages. The evolution of behaviour in these species is thus expected be influenced by multiple possibly...