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.
2023
Authors
Juliana D. Klein Simo Maduna Matthew L. Dicken Charlene Da Silva Michelle Soekoe Meaghen E. McCord Warren M. Potts Snorre Hagen Aletta E Bester-van der MerweAbstract
Adaptive divergence in response to environmental clines are expected to be common in species occupying heterogeneous environments. Despite numerous advances in techniques appropriate for non-model species, gene–environment association studies in elasmobranchs are still scarce. The bronze whaler or copper shark (Carcharhinus brachyurus) is a large coastal shark with a wide distribution and one of the most exploited elasmobranchs in southern Africa. Here, we assessed the distribution of neutral and adaptive genomic diversity in C. brachyurus across a highly heterogeneous environment in southern Africa based on genome-wide SNPs obtained through a restriction site-associated DNA method (3RAD). A combination of differentiation-based genome-scan (outflank) and genotype–environment analyses (redundancy analysis, latent factor mixed models) identified a total of 234 differentiation-based outlier and candidate SNPs associated with bioclimatic variables. Analysis of 26,299 putatively neutral SNPs revealed moderate and evenly distributed levels of genomic diversity across sites from the east coast of South Africa to Angola. Multivariate and clustering analyses demonstrated a high degree of gene flow with no significant population structuring among or within ocean basins. In contrast, the putatively adaptive SNPs demonstrated the presence of two clusters and deep divergence between Angola and all other individuals from Namibia and South Africa. These results provide evidence for adaptive divergence in response to a heterogeneous seascape in a large, mobile shark despite high levels of gene flow. These results are expected to inform management strategies and policy at the national and regional level for conservation of C. brachyurus populations.
Authors
Albert Kjartan Dagbjartarson Imsland Patrick Reynolds Lauri Teemu Kapari Simo Maduna Snorre Hagen Anna Hanssen Ólöf Dóra Bartels JónsdóttirAbstract
The aim of this study was to evaluate whether sea lice grazing efficiency, behaviour, size variation and cataract development can be improved through selective breeding of lumpfish. A series of studies was conducted over a four-year period where distinctive lumpfish families were established initially from wild caught mature fish and latterly from established breeding lines. Four subsequent trials (called: Phase I-IV) with ten families of lumpfish (N = 480) with a mean (± SD) weight of 46.4 ± 9.4 g (Phase I), 54.8 ± 9.2 g (Phase II), 42.0 ± 7.4 g (Phase III) and 31.3 ± 2.4 g (Phase IV) were distributed among ten sea cages (5 × 5 × 5 m) during autumn 2018 to spring 2022, each stocked with 400–404 Atlantic salmon with an average initial mean (± SD) of 387 ± 9 g (Phase I), 621 ± 15 g (Phase II), 280 ± 16 g (Phase III) and 480 ± 66 g (Phase IV). All the ten cages were stocked with 48 lumpfish (12% stocking density). In all phases there was a large inter-family variation of lice grazing of lumpfish of both L. salmonis and C. elongatus. When sea lice grazing was scaled in relation to sea lice infestation numbers on the salmon the highest sea lice grazing activity was found in Phase IV and in particular in families sired from farmed parents. There was a general trend for mean start weights and standard deviations to decrease as the phases continued. A significant increase was found in frequency of behaviour associated with feeding on natural food sources and grazing sea lice from salmon during each subsequent phase. The increase in incidence of cataracts from start to end of each trial phase was significantly reduced from Phase I (16%) to Phase IV (2%). Overall, present findings showed that sea lice grazing of both L. salmonis and C. elongatus, size variation, cataract prevalence and behaviour types can be enhanced through selection and targeted breeding programs.
Abstract
The adults of the new species Zachvatkinibates svanhovdi A. Seniczak & S. Seniczak sp. nov. are described and illustrated from Norway, and this is the first finding of Zachvatkinibates Shaldybina, 1973 in Fennoscandia. This species is the most similar to Z. quadrivertex (Halbert, 1920), but differs from it mainly by the shape of notogastral setae, posterior tectum of notogaster and lack of postanal porose area Ap, which in Z. quadrivertex is present. In Z. svanhovdi, the prodorsal seta in is long, translamella is narrow, notogastral setae are short and distally pliable, notogastral porose areas are usually oval and of medium size, but Aa can be larger, especially in males. Dorsal crest on tarsus I is present. The cytochrome oxidase I (COI) barcodes (length: 658 bp) of five specimens of the new species are provided; the maximum variation within the species was 2.41% (p-dist). The morphology and ecology of the new species is compared with other Zachvatkinibates species. The knowledge on family Punctoribatidae in Fennoscandia is updated, and Mycobates carli (Schweizer, 1922) is first reported from Norway.
Abstract
No abstract has been registered
Abstract
The morphological ontogeny of Nanhermannia sellnicki Forsslund, 1958 is described and illustrated. In all juvenile stages the bothridial seta is minute, and two pairs of exobothridial setae are present (exa reduced to its alveolus, exp short). In the larva, the seta f1 is setiform but in the nymphs it is unobservable among cuticular tubercles. Most prodorsal and gastronotal setae of the larva are short while thouse of nymphs are long; seta in and all gastronotal and adanal setae are inserted in small individual depressions. In all instars the leg segments are oval in cross section and relatively thick, and most setae on tarsi are relatively short, thick or conical. The seta d accompanies solenidion σ on all genua, φ1 on tibia I and φ on other tibiae.
Abstract
The morphological ontogeny of Zachvatkinibates svanhovdi A. Seniczak & S. Seniczak, 2023 is described and illustrated. The juveniles of this species are light brown with slightly darker colour on the prodorsum, gastronotal shield, surrounding of gla opening, and legs. The larva has 12 pairs of gastronotal setae, most are of medium size and barbed; the nymphs have 15 pairs, most are short and smooth. In all juveniles, the setae of c-series are inserted on unsclerotized integument. In the larva, the pygidial shield is absent but, in the nymphs, the gastronotal shield is present and the setae p2 and p3 are inserted on unsclerotized integument. In the larva, a humeral organ is absent but is present in the nymphs.
Abstract
Through their ephemeral reproductive structures (fruiting bodies), ectomycorrhizal forest soil fungi provide a resource for a plethora of organisms. Thus, resolving what biotic and abiotic factors determine the occurrence and abundance of fruiting bodies is fundamental for understanding the dynamics of forest trophic networks. While the influence of abiotic factors such as moisture and temperature on fungal fruiting are relatively well established, little is known about how these processes interact with the evolutionary history of fungal species to determine when, where, and in which abundance fungal fruiting bodies will emerge. A specific knowledge gap relates to whether species' responses to their environment are phylogenetically structured. Here, we ask whether related fungal taxa respond similarly to climatic factors and forest habitat characteristics, and whether such correlated responses will affect the assembly of fungal fruiting communities. To resolve these questions, we fitted joint species distribution models combining data on the species composition and abundance of fungal fruiting bodies, environmental variation, and phylogenetic relationships among fungal taxa. Our results show that both site-level forest characteristics (dominant tree species and forest age) and climatic factors related to phenology (effective heat sum) greatly influence the occurrence and abundance of fruiting bodies. More importantly, while different fungal species responded unequally to their shared environment, there was a strong phylogenetic signal in their responses, so that related fungal species tended to fruit under similar environmental conditions. Thus, not only are fruiting bodies short-lived and patchily distributed, but the availability of similar resources will be further aggregated in time and space. These strong constraints on resource availability for fungus-associated taxa highlight the potential of fungus-based networks as a model system for studies on the ecology and evolution of resource–consumer relations in ephemeral systems of high spatiotemporal patchiness.
Abstract
Resource specialization and ecological speciation arising through host-associated genetic differentiation (HAD) are frequently invoked as an explanation for the high diversity of plant-feeding insects and other organisms with a parasitic lifestyle. While genetic studies have demonstrated numerous examples of HAD in insect herbivores, the rarity of comparative studies means that we still lack an understanding of how deterministic HAD is, and whether patterns of host shifts can be predicted over evolutionary timescales. We applied genome-wide single nucleotide polymorphism and mitochondrial DNA sequence data obtained through genome resequencing to define species limits and to compare host-plant use in population samples of leaf- and bud-galling sawflies (Hymenoptera: Tenthredinidae: Nematinae) collected from seven shared willow (Salicaceae: Salix) host species. To infer the repeatability of long-term cophylogenetic patterns, we also contrasted the phylogenies of the two galler groups with each other as well as with the phylogeny of their Salix hosts estimated based on RADseq data. We found clear evidence for host specialization and HAD in both of the focal galler groups, but also that leaf gallers are more specialized to single host species compared with most bud gallers. In contrast to bud gallers, leaf gallers also exhibited statistically significant cophylogenetic signal with their Salix hosts. The observed discordant patterns of resource specialization and host shifts in two related galler groups that have radiated in parallel across a shared resource base indicate a lack of evolutionary repeatability in the focal system, and suggest that short- and long-term host use and ecological diversification in plant-feeding insects are dominated by stochasticity and/or lineage-specific effects.
Authors
Tarja Sundell Juhana I. Kammonen Ella Mustanoja Vincent Biard Mervi Kunnasranta Marja Niemi Milaja Nykänen Tommi Nyman Jukka U. Palo Mia Valtonen Lars Paulin Jukka Jernvall Petri AuvinenAbstract
Fragmentation of isolated populations increases the risk of inbreeding and loss of genetic diversity. The endemic Saimaa ringed seal (Pusa hispida saimensis) is one of the most endangered pinnipeds in the world with a population of only ~ 400 individuals. The current genetic diversity of this subspecies, isolated in Lake Saimaa in Finland for ca. 1000 generations, is alarmingly low. We performed whole-genome sequencing on Saimaa ringed seals (N = 30) and analyzed the level of homozygosity and genetic composition across the individual genomes. Our results show that the Saimaa ringed seal population has a high number of runs of homozygosity (RoH) compared with the neighboring Baltic ringed seal (Pusa hispida botnica) reference population (p < 0.001). There is also a tendency for stillborn seal pups to have more pronounced RoH. Since the population is divided into semi-isolated subpopulations within the Lake Saimaa exposing the population to deleterious genomic effects, our results support augmented gene flow as a genetic conservation action. Based on our results suggesting inbreeding depression in the population, we recommend Pihlajavesi as a potential source and Southern Saimaa as a potential recipient subpopulation for translocating individuals. The Saimaa ringed seal is a recognized subspecies and therefore translocations should be considered only within the lake to avoid an unpredictable risk of disease, the introduction of deleterious alleles, and severe ecological issues for the population.
Authors
Matti T. Heino Tommi Nyman Jukka U. Palo Jenni Harmoinen Mia Valtonen Małgorzata Pilot Sanni Översti Elina Salmela Mervi Kunnasranta Risto Väinölä A. Rus Hoelzel Jouni AspiAbstract
The Saimaa ringed seal (Pusa hispida saimensis) is endemic to Lake Saimaa in Finland. The subspecies is thought to have originated when parts of the ringed seal population of the Baltic region were trapped in lakes emerging due to postglacial bedrock rebound around 9000 years ago. During the 20th century, the population experienced a drastic human-induced bottleneck. Today encompassing a little over 400 seals with extremely low genetic diversity, it is classified as endangered. We sequenced sections of the mitochondrial control region from 60 up to 125-years-old museum specimens of the Saimaa ringed seal. The generated dataset was combined with publicly available sequences. We studied how genetic variation has changed through time in this subspecies and how it is phylogenetically related to other ringed seal populations from the Baltic Sea, Lake Ladoga, North America, Svalbard, and the White Sea. We observed temporal fluctuations in haplotype frequencies and loss of haplotypes accompanied by a recent reduction in female effective population size. In apparent contrast with the traditionally held view of the Baltic origin of the population, the Saimaa ringed seal mtDNA variation also shows affinities to North American ringed seals. Our results suggest that the Saimaa ringed seal has experienced recent genetic drift associated with small population size. The results further suggest that extant Baltic ringed seal is not representative of the ancestral population of the Saimaa ringed seal, which calls for re-evaluation of the deep history of this subspecies.