Search results for "AH"
showing 10 items of 6917 documents
Protist predation can select for bacteria with lowered susceptibility to infection by lytic phages
2015
Background: Consumer-resource interactions constitute one of the most common types of interspecific antagonistic interaction. In natural communities, complex species interactions are likely to affect the outcomes of reciprocal co-evolution between consumers and their resource species. Individuals face multiple enemies simultaneously, and consequently they need to adapt to several different types of enemy pressures. In this study, we assessed how protist predation affects the susceptibility of bacterial populations to infection by viral parasites, and whether there is an associated cost of defence on the competitive ability of the bacteria. As a study system we used Serratia marcescens and i…
Lake eutrophication and brownification downgrade availability and transfer of essential fatty acids for human consumption
2016
Article
Genomic Analysis of European Drosophila melanogaster Populations Reveals Longitudinal Structure, Continent-Wide Selection, and Previously Unknown DNA…
2020
Genetic variation is the fuel of evolution, with standing genetic variation especially important for short-term evolution and local adaptation. To date, studies of spatiotemporal patterns of genetic variation in natural populations have been challenging, as comprehensive sampling is logistically difficult, and sequencing of entire populations costly. Here, we address these issues using a collaborative approach, sequencing 48 pooled population samples from 32 locations, and perform the first continent-wide genomic analysis of genetic variation in European Drosophila melanogaster. Our analyses uncover longitudinal population structure, provide evidence for continent-wide selective sweeps, ide…
Evolutionary relationships, biogeography and morphological characters of Glinus (Molluginaceae), with special emphasis on the genus composition in Su…
2021
Glinus is a small genus of Molluginaceae with 8–10 species mostly distributed in the tropics of the World. Its composition and evolutionary relationships were poorly studied. A new molecular phylogeny constructed here using nuclear (ITS) and chloroplast (rbcL, trnK-matK) markers confirmed the monophyly of the genus. Based on ITS analysis, the following well-supported lineages are present within Glinus: the G. bainesii lineage is recovered as sister to the remainder of the genus followed by G. oppositifolius. Three other clades are: G. hirtus with G. orygioides; G. radiatus and G. lotoides; the latter is represented by a sample from North America, and G. zambesiacus as sister to G. setifloru…
Selection for reproduction under short photoperiods changes diapause-associated traits and induces widespread genomic divergence.
2019
The work has been supported by the Academyof Finland to A.H. (project 267244) and Natural Environment Research Council (NERC) funding (NE/J020818/1 to M.G.R.; NE/L501852/1 to R.A.W.W.). The incidence of reproductive diapause is a critical aspect of life history in overwintering insects from temperate regions. Much has been learned about the timing, physiology and genetics of diapause in a range of insects, but how the multiple changes involved in this and other photoperiodically regulated traits are inter-related is not well understood. We performed quasinatural selection on reproduction under short photoperiods in a northern fly species, Drosophila montana, to trace the effects of photoper…
Gene flow and population admixture as the primary post-invasion processes in common ragweed (Ambrosia artemisiifolia) populations in France
2010
*An improved inference of the evolutionary history of invasive species may be achieved by analyzing the genetic variation and population differentiation of recently established populations and their ancestral (historical) populations. Employing this approach, we investigated the role of gene flow in the post-invasion evolution of common ragweed (Ambrosia artemisiifolia). *Using eight microsatellite loci, we compared genetic diversity and structure among nine pairs of historical and recent populations in France. Historical populations were reconstructed from herbarium specimens dated from the late 19th to early 20th century, whereas recent populations were collected within the last 5 yr. *Re…
Immune response affects ant trophallactic behaviour.
2008
5 pages; International audience; Sociality is associated with many benefits that have favoured its evolution in social insects. However, sociability also presents disadvantages like crowding of large numbers of individuals, which may favour the spread of infections within colonies. Adaptations allowing social insects to prevent and/or control pathogen infections range from behavioural responses to physiological ones including their immune systems. In a state of infection, social interactions with nestmates should be altered in a way which might prevent its spreading. We simulated a microbial infection in workers of the ant Camponotus fellah by the administration of peptidoglycan (PGN) and t…
Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) differ in their suitability as hosts for the endangered freshwater pearl mussel (Margari…
2017
European populations of the freshwater pearl mussel (FPM, Margaritifera margaritifera) have collapsed across much of the species’ geographic range and, despite many types of conservation intervention, the number of successful restoration efforts has been low. The goal of this study was to determine whether there were population-specific differences in the suitability of Atlantic salmon (Salmo salar) and brown trout (S. trutta) as hosts for the parasitic glochidium larvae of FPM. We predicted that such differences would depend on the historical occurrence of these salmonid species in FPM habitats. We studied the potential host specificity both in the field and in laboratory by exposing salmo…
Suppressiveness of 18 composts against 7 pathosystems : variability in pathogen response
2006
International audience; Compost is often reported as a substrate that is able to suppress soilborne plant pathogens, but suppression varies according to the type of compost and pathosystem. Reports often deal with a single pathogen while in reality crops are attacked by multiple plant pathogens. The goal of the present study was to evaluate the disease suppression ability of a wide range of composts for a range of plant pathogens. This study was conducted by a consortium of researchers from several European countries. Composts originated from different countries and source materials including green and yard waste, straw, bark, biowaste and municipal sewage. Suppressiveness of compost-amende…
Seasonal and ontogenetic variability in stomach size of Eurasian perch (Perca fluviatilis L.)
2019
Eurasian perch (Perca fluviatilis) were sampled in April, from May to June and at the end of August to test whether the current season (i.e. feeding conditions) affects the fishes’ stomach size (i.e. volume and weight). A wide range of size data were analysed to reveal the relationship between fish size (length and weight) and stomach size. No significant differences in length-specific stomach volume or stomach weight were found in fish sampled at different times of the year. However, there were differences between seasons in the size of the stomach in relation to body weight, as length-specific body weight changes during the year because of the development of gametes and changes in nutriti…