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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2022

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Abstract

Large areas of forests are annually damaged or destroyed by outbreaking insect pests. Understanding the factors that trigger and terminate such population eruptions has become crucially important, as plants, plant-feeding insects, and their natural enemies may respond differentially to the ongoing changes in the global climate. In northernmost Europe, climate-driven range expansions of the geometrid moths Epirrita autumnata and Operophtera brumata have resulted in overlapping and increasingly severe outbreaks. Delayed density-dependent responses of parasitoids are a plausible explanation for the 10-year population cycles of these moth species, but the impact of parasitoids on geometrid outbreak dynamics is unclear due to a lack of knowledge on the host ranges and prevalences of parasitoids attacking the moths in nature. To overcome these problems, we reviewed the literature on parasitism in the focal geometrid species in their outbreak range and then constructed a DNA barcode reference library for all relevant parasitoid species based on reared specimens and sequences obtained from public databases. The combined recorded parasitoid community of E. autumnata and O. brumata consists of 32 hymenopteran species, all of which can be reliably identified based on their barcode sequences. The curated barcode library presented here opens up new opportunities for estimating the abundance and community composition of parasitoids across populations and ecosystems based on mass barcoding and metabarcoding approaches. Such information can be used for elucidating the role of parasitoids in moth population control, possibly also for devising methods for reducing the extent, intensity, and duration of outbreaks.

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Abstract

Lumpfish is now the single most important cleaner fish species to date and there is an extensive lumpfish translocation along the Norwegian coast. A reliable baseline information about the population genetic structure of lumpfish is a prerequisite for an optimal managing of the species to minimize possible genetic translocation and avoid possible hybridisation and introgression with local populations. The current study is a follow up of the study of Jónsdóttir et al. (2018) using expressed sequence tag-short tandem repeats (EST-STRs) markers. Samples (N = 291) were analysed from six sample locations along the Norwegian coastline from south to north, with additional 18 samples of first-generation (from wild fish) reared fish from a fish farm outside Tromsø (North Norway). Present findings show a lack of population differentiation among lumpfish sampling population along the Norwegian coast using EST-STRs, which is in accordance with the findings of Jónsdóttir et al. (2018) where genomic STRs (g-STRs) were analysed. Present findings indicate that should translocated lumpfish escape from salmon sea pens in Norway, this will probably have little impact on the genetic composition of the local lumpfish population.

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Abstract

Aims To investigate and compare antimicrobial resistance genes (ARGs) in faeces from cohabiting dogs and owners. Methods and Results DNA from faecal samples from 35 dogs and 35 owners was screened for the presence of 34 clinically relevant ARGs using high throughput qPCR. In total, 24 and 25 different ARGs were present in the dog and owner groups, respectively. The households had a mean of 9.9 ARGs present, with dogs and owners sharing on average 3.3 ARGs. ARGs were shared significantly more in households with dogs over 6 years old (3.5, interquartile range 2.75–5.0) than in households with younger dogs (2.5, interquartile range 2.0–3.0) (p = 0.02). Dogs possessed significantly more mecA and aminoglycoside resistance genes than owners. Conclusions Dogs and owners can act as reservoirs for a broad range of ARGs belonging to several antimicrobial resistance classes. A modest proportion of the same resistance genes were present in both dogs and owners simultaneously, indicating that ARG transmission between the dog and human gut is of minor concern in the absence of antimicrobial selection. Significance and Impact of the Study This study provides insight into the common dog and human gut resistomes, contributing to an improved knowledge base in risk assessments regarding ARG transmission between dogs and humans.

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Abstract

Host-specialist parasites of endangered large vertebrates are in many cases more endangered than their hosts. In particular, low host population densities and reduced among-host transmission rates are expected to lead to inbreeding within parasite infrapopulations living on single host individuals. Furthermore, spatial population structures of directly-transmitted parasites should be concordant with those of their hosts. Using population genomic approaches, we investigated inbreeding and population structure in a host-specialist seal louse (Echinophthirius horridus) infesting the Saimaa ringed seal (Phoca hispida saimensis), which is endemic to Lake Saimaa in Finland, and is one of the most endangered pinnipeds in the world. We conducted genome resequencing of pairs of lice collected from 18 individual Saimaa ringed seals throughout the Lake Saimaa complex. Our analyses showed high genetic similarity and inbreeding between lice inhabiting the same individual seal host, indicating low among-host transmission rates. Across the lake, genetic differentiation among individual lice was correlated with their geographic distance, and assignment analyses revealed a marked break in the genetic variation of the lice in the middle of the lake, indicating substantial population structure. These findings indicate that movements of Saimaa ringed seals across the main breeding areas of the fragmented Lake Saimaa complex may in fact be more restricted than suggested by previous population-genetic analyses of the seals themselves.

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Abstract

Interactions among fungi and insects involve hundreds of thousands of species. While insect communities on plants have formed some of the classic model systems in ecology, fungus-based communities and the forces structuring them remain poorly studied by comparison. We characterize the arthropod communities associated with fruiting bodies of eight mycorrhizal basidiomycete fungus species from three different orders along a 1200-km latitudinal gradient in northern Europe. We hypothesized that, matching the pattern seen for most insect taxa on plants, we would observe a general decrease in fungal-associated species with latitude. Against this backdrop, we expected local communities to be structured by host identity and phylogeny, with more closely related fungal species sharing more similar communities of associated organisms. As a more unique dimension added by the ephemeral nature of fungal fruiting bodies, we expected further imprints generated by successional change, with younger fruiting bodies harboring communities different from older ones. Using DNA metabarcoding to identify arthropod communities from fungal fruiting bodies, we found that latitude left a clear imprint on fungus-associated arthropod community composition, with host phylogeny and decay stage of fruiting bodies leaving lesser but still-detectable effects. The main latitudinal imprint was on a high arthropod species turnover, with no detectable pattern in overall species richness. Overall, these findings paint a new picture of the drivers of fungus-associated arthropod communities, suggesting that latitude will not affect how many arthropod species inhabit a fruiting body but, rather, what species will occur in it and at what relative abundances (as measured by sequence read counts). These patterns upset simplistic predictions regarding latitudinal gradients in species richness and in the strength of biotic interactions.

Abstract

Continued anthropogenic environmental change is wreaking havoc on natural populations, with the stresses and pulses of induced ecological processes affecting a species' local habitat, resulting in inadvertent distribution shifts, hybridization events, and eventual biodiversity loss. It is more critical than ever to monitor the unintended consequences of human activity on not only natural populations, but also community structures and ecosystems. DNA-based (genetic and genomic) monitoring is a critical component of biodiversity monitoring because it allows for the tracking and quantification of temporal changes in population genetic metrics or other population data. Genetic/genomic monitoring enables the estimation of a variety of biological parameters, including demographic parameters (abundance, occupancy, hybridization, and disease status), population genetic parameters (genetic diversity, structure, and effective population size), and responses to anthropogenic selective pressures (exploitation, biological invasions, and climate change). This keynote address will highlight the practical implications of integrating genetic data into management, conservation objectives, and policymaking, as well as capacity building through international partnerships, using case studies from the Norwegian Barents Region.