Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2019
Forfattere
Alexander Kopatz Oddmund Kleven Jonas Kindberg Ilpo Kojola Jouni Aspi Göran Spong Niclas Gyllenstrand Love Dalén Ida Marie Bardalen Fløystad Snorre Hagen Øystein FlagstadSammendrag
Background The populations of brown bear (Ursus arctos) in northern Europe have been recovering or are in the process of recovery from a severe demographic bottleneck. Especially in the main popula- tions of Scandinavia and Finland, the number of individuals has been increasing substantially, compared to the population sizes estimated 20 years ago. Also, the populations have spatially expanded, putatively restoring connectivity and gene flow between these two, formerly separated populations. The Swedish Environmental Protection Agency (Naturvårdsverket) assigned a pro- ject to assess the connectivity and gene flow between the eastern and western parts of Fen- noscandia, Finland and Scandinavia. Objective Our objective was to detect possible immigration of brown bears from eastern Fennoscandia, specifically Finland, into Scandinavia. Material and Methods For the first time with continuous sampling of brown bears, we assessed the population genetic structure and gene flow between the brown bear populations of Scandinavia and Finland. We based our analyses on the dispersing sex, male brown bears, as females tend to be philopatric. Our target area was the county of Norrbotten in northern Sweden, at the border to Finland and Norway, representing the most likely area for potential eastern immigrants into Sweden. Previous research did not reveal any influx from Finland into Sweden. However, brown bear samples from Norrbotten have to a very limited degree been included in earlier studies on genetic connectivity in the area. In addition to a large number of samples from Norrbotten and northern Finland, we included genotypes sampled in regions surrounding the target area: Västerbotten in Sweden, Troms and Finnmark in Norway and southern Finland. We utilized all samples and genotypes from male bears available, and, also, genotyped recently collected samples of male brown bears from the study area. Analyses on population genetic structure and gene flow among regions were based on 924 individual male brown bear STR-genotypes (12 short tandem repeats or microsatellite markers). In order to reveal patterns of male dispersal and the distribution of male linages we used brown bear samples genotyped with nine Y-chromosomal STRs from 826 males. KEY WORDS : connectivity, european brown bear, Fennoscandia, Finland, male gene flow, migration, population genetic structure, Scandinavia, Ursus arctos NØKKELORD : europeisk brunbjørn, Fennoskandia, Finland, genflyt, konnektivitet, migrasjon, populasjons genetisk struktur, Skandinavia, Ursus arctos
Forfattere
Inger Maren Rivrud Shane Frank Richard Bischof Atle Mysterud Sam Steyaert Anne Gabriela Hertel Snorre Hagen Hans Geir Eiken Jon Swenson Andreas ZedrosserSammendrag
Wild animal populations experience selection pressures from both natural and anthropogenic sources. The availability of extensive pedigrees is increasing along with our ability to quantify the heritability and evolvability of phenotypic traits and thus the speed and potential for evolutionary change in wild populations. The environment may also affect gene expressions in individuals, which may in turn affect the potential of phenotypic traits to respond to selection. Knowledge about the relationship between the genetic and environmental components of phenotypic variation is particularly relevant, given ongoing anthropogenically driven global change. Using a quantitative genetic mixed model, we disentangled the genetic and environmental components of phenotypic variance in a large carnivore, the brown bear (Ursus arctos). We combined a pedigree covering ~1,500 individual bears over seven generations with location data from 413 bears, as well as data on bear density, habitat characteristics, and climatic conditions. We found a narrow‐sense heritability of 0.24 (95% CrI: 0.06–0.38) for brown bear head size, showing that the trait can respond to selection at a moderate speed. The environment contributed substantially to phenotypic variation, and we partitioned this into birth year (5.9%), nonadditive among‐individual genetic (15.0%), and residual (50.4%) environmental effects. Brown bear head circumference showed an evolvability of 0.2%, which can generate large changes in the trait mean over some hundreds of generations. Our study is among the first to quantify heritability of a trait in a hunted large carnivore population. Such knowledge about the degree to which species experiencing hunting can respond to selection is crucial for conservation and to make informed management decisions. We show that including important environmental variables when analyzing heritability is key to understanding the dynamics of the evolutionary potential of phenotypic traits.
Forfattere
Paul Eric Aspholm Victoria Gonzalez Julia Schregel Siv Grethe Aarnes Cornelya Klutsch Anne WikanSammendrag
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Forfattere
Tone Roksvåg AandahlSammendrag
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Forfattere
Tone Roksvåg AandahlSammendrag
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Sammendrag
Interspecific brood parasitism is common in many animal systems. Brood parasites enter the nests of other species and divert host resources for producing their own offspring, which can lead to strong antagonistic parasite–host coevolution. Here, we look at commonalities among social insect species that are victims of brood parasites, and use phylogenetic data and information on geographical range size to predict which species are most probably to fall victims to brood parasites in the future. In our analyses, we focus on three eusocial hymenopteran groups and their brood parasites: (i) bumblebees, (ii) Myrmica ants, and (iii) vespine and polistine wasps. In these groups, some, but not all, species are parasitized by obligate workerless inquilines that only produce reproductive-caste descendants.We find phylogenetic signals for geographical range size and the presence of parasites in bumblebees, but not in ants and wasps. Phylogenetic logistic regressions indicate that the probability of being attacked by one or more brood parasite species increases with the size of the geographical range in bumblebees, but the effect is statistically only marginally significant in ants. However, non-phylogenetic logistic regressions suggest that bumblebee species with the largest geographical range sizes may have a lower likelihood of harbouring social parasites than do hosts with medium-sized ranges. Our results provide new insights into the ecology and evolution of host–social parasite systems, and indicate that host phylogeny and geographical range size can be used to predict threats posed by social parasites, as well to design efficient conservation measures for both hosts and their parasites. This article is part of the theme issue ‘The coevolutionary biology of brood parasitism: from mechanism to pattern’.
Forfattere
Tommi Nyman Renske E Onstein Daniele Silvestro Saskia Wutke Andreas Taeger Niklas Wahlberg Stephan Martin Blank Tobias MalmSammendrag
The insect order Hymenoptera originated during the Permian nearly 300 Mya. Ancestrally herbivorous hymenopteran lineages today make up the paraphyletic suborder ‘Symphyta’, which encompasses c. 8200 species with very diverse host-plant associations. We use phylogeny-based statistical analyses to explore the drivers of diversity dynamics within the ‘Symphyta’, with a particular focus on the hypothesis that diversification of herbivorous insects has been driven by the explosive radiation of angiosperms during and after the Cretaceous. Our ancestral-state estimates reveal that the first symphytans fed on gymnosperms, and that shifts onto angiosperms and pteridophytes – and back – have occurred at different time intervals in different groups. Trait-dependent analyses indicate that average net diversification rates do not differ between symphytan lineages feeding on angiosperms, gymnosperms or pteridophytes, but trait-independent models show that the highest diversification rates are found in a few angiosperm-feeding lineages that may have been favoured by the radiations of their host taxa during the Cenozoic. Intriguingly, lineages-through-time plots show signs of an early Cretaceous mass extinction, with a recovery starting first in angiosperm-associated clades. Hence, the oft-invoked assumption of herbivore diversification driven by the rise of flowering plants may overlook a Cretaceous global turnover in insect herbivore communities during the rapid displacement of gymnosperm- and pteridophyte-dominated floras by angiosperms.
Sammendrag
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Sammendrag
The blacktip shark Carcharhinus limbatus is a cosmopolitan species found in warm-temperate, subtropical and tropical waters around the world. The research here aimed to assess whether multiple paternity exists in South African C. limbatus and to confirm phylogeographic patterns previously observed within the species. A minimum and maximum frequency of 50% and 71% multiple paternity, respectively, were observed in 14 litters genotyped with five microsatellite markers. Based on the mitochondrial control region, relatively high nucleotide and haplotype diversity characterised the South African sampling population, and pairwise φST values indicated that it significantly differed from the populations of the Pacific and the western Atlantic oceans. The haplotype network showed that the South African samples were grouped closely with the Australian, Indo-Pacific and West African C. limbatus samples, which is suggestive of an Indo-Pacific origin for this population. This study is the first to report multiple paternity in this species. Furthermore, the results reveal that C. limbatus from South Africa is genetically diverse and phylogeographically distinct from most other C. limbatus populations.