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
Trygve S. Aamlid Hans Martin Hanslin Ellen Johanne Svalheim H.K. Bratli Geir Kjølberg Knudsen Eivind NitterSammendrag
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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.
Forfattere
Robert BarneveldSammendrag
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Forfattere
Mehreteab TesfaiSammendrag
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Sammendrag
Legume-based cropping system and Brachiaria forage system could play a significant role in enhancing food and nutrition security and sustainable intensifications of African agriculture. To reveal this potential, a comprehensive review of literatures and assessment was performed using key indicators in relation to food and nutrition quality, agro-ecological services and socioeconomic benefits. The key indicators for legumes intercropping systems include: Grain yield, soil organic matter, food availability, nutritive values of legumes, maize and millets- based foods, proportion of income from crop sale and percentage of farmers aware and/or adopting intercropping. In the case of Brachiaria system, the forage biomass, milk yield, availability of milk, milk nutrition contents, income from Brachiaria grass and milk sale and people practising the Brachiaria technology were considered key indicators. Both systems showed positive impacts and contribute to a range of the United Nation’s sustainable development goals including 1, 2, 3, 12, 13 and 15 and other associated targets. Integrating legume-based cropping systems and Brachiaria forage system will enhance contributions of smallholder farmers to food and nutrition security. The necessary changes needed in technology, institutions and policies to upscale legume-based cropping systems and Brachiaria forage system were suggested. These changes include improved varieties, quality seeds, improved cultivation practices, market provision, effective extension and advisory services and support to the seed productions and distribution systems, among others. Yet, to fully tap the potentials of legume-based and Brachiaria forage systems sustainably and raise the profile of these climate smart systems, context specific research measures are necessary.
Sammendrag
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Forfattere
Junbin ZhaoSammendrag
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Forfattere
James Fourqurean Sparkle Malone Edward Castaneda Sean Charles Carl Fitz Daniel Gann David Ho John Kominoski Christian Lopes Steven. F. Oberbauer Gregory Starr Christina Staudhammer Tiffany Troxler Bryce Van Dam Junbin ZhaoSammendrag
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Forfattere
Junbin ZhaoSammendrag
As the main drivers of climate change, greenhouse gas (e.g., CO2 and CH4) emissions have been monitored intensively across the globe. The static chamber is one of the most commonly used approaches for measuring greenhouse gas fluxes from ecosystems (e.g., stem/soil respiration, CH4 emission, etc.) because of its easy implementation, high accuracy and low cost (Pumpanen et al., 2004). To perform the measurements, a gas analyzer is usually used to measure the changes of greenhouse gas concentrations within a closed chamber that covers an area of interest (e.g., soil surface) over a certain period of time (usually several minutes). The flux rates (F) are then calculated from the recorded gas concentrations assuming that the changing rate is linear: F = vol/(R · T a · area) · dG/dt where vol is the volume of the chamber (l), R is the universal gas constant (l atm K-1 mol-1), Ta is the ambient temperature (K), area is the area of the chamber base (m2 ), and dG/dt is the rate of the measured gas concentration change over time t (ppm s-1) (i.e., the slope of the linear regression).