Hans Petter Leinaas

• Möllerke, Anton; Montes Vidal, Diogo; Leinaas, Hans Petter & Schulz, Stefan (2024). Socialane, a Nonaprenyl Terpene Hydrocarbon Surface Lipid from the Collembola Hypogastrura socialis. Chemistry - A European Journal. ISSN 0947-6539. doi: 10.1002/chem.202400272.
• Möllerke, Anton; Bello, Jan; Leinaas, Hans Petter & Schulz, Stefan (2023). Cyclopropane Hydrocarbons from the Springtail Vertagopus sarekensis─A New Class of Cuticular Lipids from Arthropods. Journal of natural products. ISSN 0163-3864. 87(1), s. 85–97. doi: 10.1021/acs.jnatprod.3c00789. Fulltekst i vitenarkiv
• Silva, Andreia Sofia Jorge; Kristiansen, Silje Marie; Sengupta, Sagnik; van Gestel, Cornelis A. M.; Leinaas, Hans Petter & Borgå, Katrine (2023). Using dietary exposure to determine sub-lethal effects from imidacloprid in two springtail (Collembola) species. Ecotoxicology. ISSN 0963-9292. 32, s. 1209–1220. doi: 10.1007/s10646-023-02715-x. Fulltekst i vitenarkiv
• Sengupta, Sagnik; Leinaas, Hans Petter; van Gestel, Cornelis A.M.; Jager, Tjalling; Rundberget, Thomas & Borgå, Katrine (2023). High sensitivity to dietary imidacloprid exposure in early life stages of Folsomia quadrioculata (Collembola) populations from contrasting climates. Agriculture, Ecosystems & Environment. Applied Soil Ecology. ISSN 0929-1393. 187. doi: 10.1016/j.apsoil.2023.104880. Fulltekst i vitenarkiv Vis sammendrag

  Survival of early life stages is critical for population growth. Understanding the vulnerability of these sensitive stages can therefore improve ecological risk predictions. The globally-used neonicotinoid insecticide imidacloprid does not degrade easily in soil and occurs at concentrations potentially toxic to non-target soil organisms, such as Collembola. Here, we studied the effects of dietary exposure to imidacloprid on the survival of juveniles in an arctic and a temperate population of Folsomia quadrioculata (Collembola), a commonly-occurring litter-dwelling species in the Northern Hemisphere. The exposure lasted from <24 h to 30 days since hatching at 15 °C. We assessed whether (1) the arctic population of the test species with faster development rates could be more vulnerable than the temperate population, (2) cumulative mortality could increase substantially with exposure time, and (3) the mortality risk experienced during the juvenile stage could be greater than that experienced by the adults. We found a strong concentration-dependent decline in survival in both populations, with small but significantly different LC50s, despite large differences in multiple life-history traits. Applying a General Unified Threshold model for Survival (GUTS) showed a low threshold for effects, slow damage dynamics, a 6–11-fold decrease in LC50 from 14 to 30 days of exposure, and saturation of damage at the three highest concentrations. In addition, exposure starting soon after hatching caused much more mortality than that starting in the adult stages. Our findings suggest that toxicity tests not emphasizing the neonate stages or not lasting long enough can underestimate the implications for populations of naturally abundant non-target organisms.

• Konestabo, Heidi Sjursen; Birkemoe, Tone; Leinaas, Hans Petter; van Gestel, Cornelis A.M.; Sengupta, Sagnik & Borgå, Katrine (2022). Pesticide effects on the abundance of springtails and mites in field mesocosms at an agricultural site. Ecotoxicology. ISSN 0963-9292. 31(9), s. 1450–1461. doi: 10.1007/s10646-022-02599-3. Fulltekst i vitenarkiv
• Kristiansen, Silje Marie; Borgå, Katrine; Rundberget, Jan Thomas & Leinaas, Hans Petter (2021). Effects on Life-History Traits of Hypogastrura viatica (Collembola) Exposed to Imidacloprid Through Soil or Diet. Environmental Toxicology and Chemistry. ISSN 0730-7268. 40(11), s. 3111–3122. doi: 10.1002/etc.5187. Fulltekst i vitenarkiv Vis sammendrag

  Collembola (springtails) are important members of soil communities worldwide by contributing to degradation of organic matter. In nature, Collembola might be exposed to the neonicotinoid insecticide imidacloprid, which is fairly persistent in soil. We exposed the widespread Hypogastrura viatica to imidacloprid through soil or food and monitored the animals during exposure and a post exposure period. We recorded effects on life-history traits affecting individual fitness, that is, mortality, behavioral activity, several reproduction traits, and molting frequency. Exposure through soil led to a concentration-dependent mortality, while the mortality from dietary exposure possibly reflected reduced feeding activity. The body burden of imidacloprid in the Collembola did not differ between treatments. We found no sign of recovery in behavioral activity following exposure in either experiment. The egg production of H. viatica was not significantly affected by imidacloprid at 0.01 mg/kg dry soil but showed a tendency to reduce number of eggs per batch and reduced hatching success. At higher concentrations, reproduction was close to, or completely, stopped. The molting frequency decreased during exposure, while in the post exposure period, we saw milder effects at the highest concentrations, suggesting elimination through molting or reduced toxic response as a result of reduced feeding activity. Overall, H. viatica was more sensitive to imidacloprid than previously studied Collembola, which highlights the importance of considering species sensitivities when risk-assessing soil environments.

• Hasle, Gunnar; Leinaas, Hans Petter; Heier, Lise; Garcia, Aïda Lopez & Røed, Knut (2021). Mitochondrial DNA in Ixodus ricinus (Acari: Ixodidae) on birds reflects ticks’ transportation routes to Lista, Norway. Ticks and Tick-borne Diseases. ISSN 1877-959X. 12(1), s. 1–7. doi: 10.1016/j.ttbdis.2020.101553.
• Sengupta, Sagnik; Leinaas, Hans Petter; van Gestel, Cornelis A.M.; Rundberget, Jan Thomas & Borgå, Katrine (2020). A Multiple Life‐History Trait–Based and Time‐Resolved Assessment of Imidacloprid Effects and Recovery in the Widely Distributed Collembolan Folsomia quadrioculata. Environmental Toxicology and Chemistry. ISSN 0730-7268. 40(1), s. 139–147. doi: 10.1002/etc.4897. Vis sammendrag

  Life history traits determine individual fitness and the fate of populations. Imidacloprid, a widely used neonicotinoid insecticide, which persists in soil for more than 100 d at biologically relevant levels, may affect non‐target and ecologically important species, such as collembolans. In the present study, we determined the sublethal effects of short‐term imidacloprid exposure and post‐exposure recovery in the collembolan Folsomia quadrioculata, which occurs abundantly across the northern hemisphere. We assessed survival, egg production, and hatching success in adult springtails exposed for 14 d through the diet to imidacloprid followed by a 28 d post‐exposure phase. Survival and hatching success were high throughout the experiment in all the treatments, with no clear concentration dependency. However, egg production declined during the exposure phase and nearly stopped between 8 and 14 d in all the treatments (except the control), but resumed during the post‐exposure phase. Moreover, the resumption of egg production showed a concentration‐dependent delay. Our findings suggest that low imidacloprid exposures can restrict reproduction, with potentially severe consequences for the population, notwithstanding the partial recovery in egg production.

• Janion-Scheepers, Charlene; Bengtsson, Jan; Duffy, Grant A.; Deharveng, Louis; Leinaas, Hans Petter & Chown, Steven L. (2020). High spatial turnover in springtails of the Cape Floristic Region. Journal of Biogeography. ISSN 0305-0270. 47(5), s. 1007–1018. doi: 10.1111/jbi.13801. Fulltekst i vitenarkiv
• Poli, Pedro; Lenoir, Jonathan; Plantard, Olivier; Ehrmann, Steffen; Røed, Knut & Leinaas, Hans Petter [Vis alle 8 forfattere av denne artikkelen] (2020). Strong genetic structure among populations of the tick Ixodes ricinus across its range. Ticks and Tick-borne Diseases. ISSN 1877-959X. 11(6), s. 1–10. doi: 10.1016/j.ttbdis.2020.101509. Vis sammendrag

  Ixodes ricinus is the most common and widely distributed tick species in Europe, responsible for several zoonotic diseases, including Lyme borreliosis. Population genetics of disease vectors is a useful tool for understanding the spread of pathogens and infection risks. Despite the threat to the public health due to the climate-driven distribution changes of I. ricinus, the genetic structure of tick populations, though essential for understanding epidemiology, remains unclear. Previous studies have demonstrated weak to no apparent spatial pattern of genetic differentiation between European populations. Here, we analysed the population genetic structure of 497 individuals from 28 tick populations sampled from 20 countries across Europe, the Middle-East, and northern Africa. We analysed 125 SNPs loci after quality control. We ran Bayesian and multivariate hierarchical clustering analyses to identify and describe clusters of genetically related individuals. Both clustering methods support the identification of three spatially-structured clusters. Individuals from the south and north-western parts of Eurasia form a separated cluster from northern European populations, while central European populations are a mix between the two groups. Our findings have important implications for understanding the dispersal processes that shape the spread of zoonotic diseases under anthropogenic global changes.

• Kristiansen, Silje Marie; Leinaas, Hans Petter; Herzke, Dorte; Hylland, Ketil; Gabrielsen, Geir W. & Harju, Mikael [Vis alle 7 forfattere av denne artikkelen] (2019). Seabird-transported contaminants are reflected in the Arctic tundra, but not in its soil-dwelling springtails (Collembola). Environmental Science and Technology. ISSN 0013-936X. 53(21), s. 12835–12845. doi: 10.1021/acs.est.9b05316.
• Bello, Jan E; Stamm, Patrick; Leinaas, Hans Petter & Schulz, Stefan (2019). Viaticene A - An Unusual Tetraterpene Cuticular Lipid Isolated from the Springtail Hypogastrura viatica. European Journal of Organic Chemistry. ISSN 1434-193X. 2019(11), s. 2158–2162. doi: 10.1002/ejoc.201900224.
• Widenfalk, Lina A.; Leinaas, Hans Petter; Bengtsson, Jan & Birkemoe, Tone (2018). Age and level of self-organization affect the small-scale distribution of springtails (Collembola). Ecosphere. ISSN 2150-8925. 9(1). doi: 10.1002/ecs2.2058. Fulltekst i vitenarkiv
• Eisenhauer, Nico; Antunes, Pedro; Bennett, Alison E; Birkhofer, Klaus; Bissett, Andrew & Bowker, Matthew A [Vis alle 32 forfattere av denne artikkelen] (2017). Priorities for research in soil ecology. Pedobiologia. ISSN 0031-4056. 63, s. 1–7. doi: 10.1016/j.pedobi.2017.05.003.
• Gundersen, Håkon A Holm; Leinaas, Hans Petter & Thaulow, Christian (2017). Collembola cuticles and the three-phase line tension. Beilstein Journal of Nanotechnology. ISSN 2190-4286. 8(1), s. 1714–1722. doi: 10.3762/bjnano.8.172. Fulltekst i vitenarkiv
• Sengupta, Sagnik; Ergon, Torbjørn & Leinaas, Hans Petter (2017). Thermal plasticity in postembryonic life history traits of a widely distributed Collembola: Effects of macroclimate and microhabitat on genotypic differences. Ecology and Evolution. ISSN 2045-7758. 7(19), s. 8100–8112. doi: 10.1002/ece3.3333. Fulltekst i vitenarkiv
• Alfsnes, Kristian; Leinaas, Hans Petter & Hessen, Dag Olav (2017). Genome size in arthropods; different roles of phylogeny, habitat and life history in insects and crustaceans. Ecology and Evolution. ISSN 2045-7758. 7(15), s. 5939–5947. doi: 10.1002/ece3.3163. Fulltekst i vitenarkiv
• Røed, Knut; Kvie, Kjersti; Hasle, Gunnar; Gilbert, Lucy & Leinaas, Hans Petter (2016). Phylogenetic Lineages and Postglacial Dispersal Dynamics Characterize the Genetic Structure of the Tick, Ixodes ricinus, in Northwest Europe. PLOS ONE. ISSN 1932-6203. 11(12). doi: 10.1371/journal.pone.0167450. Fulltekst i vitenarkiv
• Janion-Scheepers, Charlene; Bengtsson, Jan; Leinaas, Hans Petter; Deharveng, Louis & Chown, Steven L. (2016). The response of springtails to fire in the fynbos of the Western Cape, South Africa. Agriculture, Ecosystems & Environment. Applied Soil Ecology. ISSN 0929-1393. 108, s. 165–175. doi: 10.1016/j.apsoil.2016.08.001.
• Leinaas, Hans Petter; Jalal, Marwa; Gabrielsen, Tove M. & Hessen, Dag Olav (2016). Inter- and intraspecific variation in body- and genome size in calanoid copepods from temperate and arctic waters. Ecology and Evolution. ISSN 2045-7758. 6(16), s. 5585–5595. doi: 10.1002/ece3.2302. Fulltekst i vitenarkiv
• Sengupta, Sagnik; Ergon, Torbjørn & Leinaas, Hans Petter (2016). Genotypic differences in embryonic life history traits of Folsomia quadrioculata (Collembola: Isotomidae) across a wide geographical range. Ecological Entomology. ISSN 0307-6946. 41(1), s. 72–84. doi: 10.1111/een.12270.
• Leinaas, Hans Petter; Bengtsson, Jan; Janion-Scheepers, Charlene & Chown, Steven L. (2015). Indirect effects of habitat disturbance on invasion: Nutritious litter from a grazing resistant plant favors alien over native Collembola. Ecology and Evolution. ISSN 2045-7758. 5(16), s. 3462–3471. doi: 10.1002/ece3.1483. Fulltekst i vitenarkiv
• Gundersen, Håkon A Holm; Thaulow, Christian & Leinaas, Hans Petter (2015). Seasonal change in the wetting characteristics of the cuticle of the Collembola Cryptopygus clavatus (Schött, 1893). Zoomorphology. ISSN 0720-213X. 134(2), s. 211–218. doi: 10.1007/s00435-015-0254-y. Fulltekst i vitenarkiv
• Schnug, Lisbeth; Ergon, Torbjørn; Jakob, Lena; Scott-Fordsmand, Janeck J; Joner, Erik & Leinaas, Hans Petter (2015). Responses of earthworms to repeated exposure to three biocides Applied singly and as a mixture in an agricultural field. Science of the Total Environment. ISSN 0048-9697. 505, s. 223–235. doi: 10.1016/j.scitotenv.2014.09.089.
• Røed, Knut H.; Birkemoe, Tone; Sverdrup-Thygeson, Anne; Horak, Jakub; Midthjell, Liv & Leinaas, Hans Petter (2014). Isolation and characterization of ten microsatellite loci for the wood-living and threatened beetle Cucujus cinnaberinus (Coleoptera: Cucujidae). Conservation Genetics Resources. ISSN 1877-7252. 6(3), s. 641–643. doi: 10.1007/s12686-014-0164-1.
• Gundersen, Håkon A Holm; Leinaas, Hans Petter & Thaulow, Christian (2014). Surface structure and wetting characteristics of Collembola cuticles. PLOS ONE. ISSN 1932-6203. 9(2), s. 1–11. doi: 10.1371/journal.pone.0086783. Fulltekst i vitenarkiv
• Schnug, Lisbeth; Jensen, John; Scott-Fordsmand, Janeck J & Leinaas, Hans Petter (2014). Toxicity of three biocides to springtails and earthworms in a soil multi-species (SMS) test system. Soil Biology and Biochemistry. ISSN 0038-0717. 74, s. 115–126. doi: 10.1016/j.soilbio.2014.03.007.
• Schnug, Lisbeth; Leinaas, Hans Petter & Jensen, John (2014). Synergistic sub-lethal effects of a biocide mixture on the springtail Folsomia fimetaria. Environmental Pollution (1987). ISSN 0269-7491. 186, s. 158–164. doi: 10.1016/j.envpol.2013.12.004.
• Hessen, Dag Olav; Daufresne, Martin & Leinaas, Hans Petter (2013). Temperature-size relations from the cellular-genomic perspective. Biological Reviews. ISSN 1464-7931. 88(2), s. 476–489. doi: 10.1111/brv.12006.
• Bengtsson, Jan; Janion, Charlene; Chown, Steven L. & Leinaas, Hans Petter (2012). Litter decomposition in fynbos vegetation, South Africa. Soil Biology and Biochemistry. ISSN 0038-0717. 47, s. 100–105. doi: 10.1016/j.soilbio.2011.11.023.
• Janion, Charlene; Bedos, Anne; Bengtsson, Jan; Deharveng, Louis; Jansen van Vuuren, Bettine & Leinaas, Hans Petter [Vis alle 10 forfattere av denne artikkelen] (2011). Springtail diversity in South Africa. South African Journal of Science. ISSN 0038-2353. 107(11-12), s. 75–81. doi: 10.4102/sajs.v107i11/12.582.
• Hobæk, Thor Christian; Leinan, Kristian Greger; Leinaas, Hans Petter & Thaulow, Christian (2011). Surface Nanoengineering Inspired by Evolution. BioNanoScience. ISSN 2191-1630. 1(3), s. 63–77. doi: 10.1007/s12668-011-0014-5.
• Wojewodzic, Marcin; Rachamim, Tamar; Andersen, Tom; Leinaas, Hans Petter & Hessen, Dag Olav (2011). Effect of temperature and dietary elemental composition on RNA/protein ratio in a rotifer. Functional Ecology. ISSN 0269-8463. 25(5), s. 1154–1160. doi: 10.1111/j.1365-2435.2011.01864.x.
• Hasle, Gunnar; Leinaas, Hans Petter; Røed, Knut H. & Oines, Oivind (2011). Transport of Babesia venatorum-infected Ixodes ricinus to Norway by northward migrating passerine birds. Acta Veterinaria Scandinavica (AVS). ISSN 0044-605X. 53(41). doi: 10.1186/1751-0147-53-41.
• Bengtsson, Jan; Janion, Charlene; Chown, Steven L. & Leinaas, Hans Petter (2011). Variation in decomposition rates in the fynbos biome, South Africa: the role of plant species and plant stoichiometry. Oecologia. ISSN 0029-8549. 165(1), s. 225–235. doi: 10.1007/s00442-010-1753-7.
• Hasle, Gunnar; Bjune, Gunnar Aksel; Midthjell, Liv; Røed, Knut H. & Leinaas, Hans Petter (2011). Transport of Ixodes ricinus infected with Borrelia species to Norway by northward-migrating passerine birds. Ticks and Tick-borne Diseases. ISSN 1877-959X. 2(1), s. 37–43. doi: 10.1016/j.ttbdis.2010.10.004.
• Aak, Anders; Birkemoe, Tone & Leinaas, Hans Petter (2011). Phenology and life history of the blowfly Calliphora vicina in stockfish production areas. Entomologia Experimentalis et Applicata. ISSN 0013-8703. 139(1), s. 35–46. doi: 10.1111/j.1570-7458.2011.01105.x.
• Janion, Charlene; Leinaas, Hans Petter; Terblanche, John s. & Chown, Steven L. (2010). Trait means and reaction norms: the consequences of climate change/invasion interactions at the organism level. Evolutionary Ecology. ISSN 0269-7653. 24(6), s. 1365–1380. doi: 10.1007/s10682-010-9405-2.
• Hasle, Gunnar; Bjune, Gunnar Aksel; Christensson, Dan; Røed, Knut H.; Whist, Anne Cathrine & Leinaas, Hans Petter (2010). Detection of Babesia divergens in southern Norway by using an immunofluorescence antibody test in cow sera. Acta Veterinaria Scandinavica (AVS). ISSN 0044-605X. 52. doi: 10.1186/1751-0147-52-55.
• Hasle, Gunnar; Horak, I.g.; Grieve, G.; Leinaas, Hans Petter & Clarke, F. (2009). Ticks collected from birds in the northern provinces of South Africa, 2004-2006. Onderstepoort Journal of Veterinary Research. ISSN 0030-2465. 76(2), s. 167–175.
• Leinaas, Hans Petter; Slabber, Sarette & Chown, Steven L. (2009). Effects of thermal acclimation on water loss rate and tolerance in the collembolan Pogonognathellus flavescens. Physiological entomology (Print). ISSN 0307-6962. 34, s. 325–332. doi: 10.1111/j.1365-3032.2009.00693.x.
• Hasle, Gunnar; Bjune, Gunnar Aksel; Edvardsen, Erik; Jakobsen, Christer; Linnehol, Bjørn & Røer, Jan Erik [Vis alle 10 forfattere av denne artikkelen] (2009). Transport of ticks by migratory passerine birds to Norway. Journal of Parasitology. ISSN 0022-3395. 95(6), s. 1342–1351. doi: 10.1645/GE-2146.1.
• Hasle, Arne Gunnar; Roed, KH & Leinaas, Hans Petter (2008). Multiple paternity in Ixodes ricinus (Acari : Ixodidae), assessed by microsatellite markers. Journal of Parasitology. ISSN 0022-3395. 94, s. 345–347.
• Slabber, S; Worland, MR; Leinaas, Hans Petter & Chown, SL (2007). Acclimation effects on thermal tolerances of springtails from sub-Antarctic Marion Island: Indigenous and invasive species. Journal of insect physiology. ISSN 0022-1910. 53. doi: 10.1016/j.jinsphys.2006.10.010.
• Chown, Steven L.; Slabber, S; McGeoch, Melodie A; Janion, Charlene & Leinaas, Hans Petter (2007). Phenotypic plasticity mediates climate change responses among invasive and indigenous arthropods. Proceedings of the Royal Society of London. Biological Sciences. ISSN 0962-8452. 274, s. 2531–2537. doi: 10.1098/rspb.2007.0772.
• Jensen, Thomas Correll; Leinaas, Hans Petter & Hessen, Dag Olav (2006). Age-dependent shift in response to food element composition in Collembola: contrasting effects of dietary nitrogen. Oecologia. ISSN 0029-8549. 149, s. 583–592.
• Røed, Knut H.; Hasle, Gunnar; Midthjell, V.; Skretting, Grethe & Leinaas, Hans Petter (2006). Identification and characterization of 17 microsatellite primers for the tick, Ixodes ricinus, using enriched genomic libraries. Molecular Ecology Notes. ISSN 1471-8278. 6, s. 1165–1167.
• Worland, M. Roger; Leinaas, Hans Petter & Chown, Steven L. (2006). Supercooling point frequency distributions in Collembola are affected by moulting. Functional Ecology. ISSN 0269-8463. 20, s. 323–329.
• Chown, Steven L.; Sinclair, Brent J.; Leinaas, Hans Petter & Gaston, Kevin J. (2004). Hemispheric Asymmetries in Biodiversity - A Serious Matter for Ecology. PLoS Biology. ISSN 1544-9173. 2(11), s. 1701–1707. doi: 10.1371/journal.pbio.0020406.
• Ims, Rolf Anker; Leinaas, Hans Petter & Coulson, Stephen J (2004). Spatial and temporal variation in patch occupancy and population density in a model system of an arctic Collembola species assemblage. Oikos. ISSN 0030-1299. 105, s. 89–100.
• Søvik, Guldborg & Leinaas, Hans Petter (2003). Adult survival and reproduction in an arctic mite, Ameronothrus lineatus (Acari, Oribatidae): effects of temperature and winter cold. Canadian Journal of Zoology. ISSN 0008-4301. 81, s. 1579–1588.
• Søvik, Guldborg; Leinaas, Hans Petter; Ims, Rolf Anker & Solhøy, Torstein (2003). Population dynamics and life history of the oribatid mite Ameronothrue lineatus (Thorell 1871) (Oribatida, Acari) on the high arctic archipelago of Svalbard; a field study. Pedobiologia. ISSN 0031-4056. 47, s. 257–271.
• Søvik, Guldborg & Leinaas, Hans Petter (2003). Experimental field studies on development and survival in the arctic mite, Ameronothrus lineatus (Acari, Oribatidae) on a cyanobacteria surface in the High Arctic. Polar Biology. ISSN 0722-4060. 26, s. 500–508.
• Søvik, Guldborg & Leinaas, Hans Petter (2002). Variation in extraction efficiency between juvenile and adult oribatid mites: Ameronothrus lineatus (Oribatida, Acari) in a Macfadyen high-gradient canister extractor. Pedobiologia. ISSN 0031-4056. 46, s. 34–41.
• Leinaas, Hans Petter (2001). UV-tolerance, pigmentation and life forms in high arctic Collembola. I Hessen, Dag Olav (Red.), UV Radiation and Arctic Ecosystems, Ecological Studies 153. Springer. ISSN 3-540-42106-8. s. 123–134. Vis sammendrag

  Very little information exists on effects of UV-radiation on terrestrial invertebrates, and nothing from the Arctic. In this region the Collembola (springtails) is a dominant group of terrestrial invertebrates and therefore interesting to study in relation to effects of high latitude increase in UV-radiation. Most collembolan families show similar, convergent patterns in pigmentation and vertical distribution: Surface dwelling species in exposed habitats are generally very dark, which is regarded as a primitive trait. Species living below vegetation and litter are paler, and typical soil species are unpigmented. Three species often coexisting on Svalbard, but with differential vertical distribution, showed strong negative relation between UV-B tolerance and degree of reduced pigmentation. A fourth species, belonging to an originally unpigmented soil dwelling collembolan subfamily, was included in the test because it has occupied a more surface near habitat than most of its relatives. It has attained a pale pigmentation that appeared to have a surprisingly strong photo protective effect. Only the unpigmented species were seriously affected by UV-A radiation. The results indicate that UV-protection might be important also for species associated with habitats not exposed to direct sunlight. A steep gradient in UV-exposure close to the surface may potentially have an impact on structuring species assemblages both vertically and horizontally, and most likely in patchy habitats with differential vegetation cover. Increased UV-radiation due to ozone degradation at high latitude may further affect the population dynamics and occurrence of species, but any effect will probably depend on life form. Increased mortality for several days after experimental radiation shows that irreversible damages may occur long before detected by direct measurements of survival during exposure.

• Birkemoe, Tone & Leinaas, Hans Petter (2001). Growth and development in a high Arctic Collembola: adaptive variation in local populations living in contrasting thermal environments. Ecological Entomology. ISSN 0307-6946. 26, s. 100–105. doi: 10.1046/j.1365-2311.2001.00292.x. Vis sammendrag

  1. Terrestrial polar invertebrates with wide geographical distribution must complete their life cycle at sites with large differences in thermal regimes. Here we test whether local adaptation of growth and development to temperature has taken place in the Arctic Collembola Hypogastrura tullbergi. 2. Growth and development of two populations from sites with very different climatic regimes (e.g. from different latitudes) are compared at 5, 10 and 15°C. These temperatures are encountered in the daily fluctuations in the habitat of the southern population. 3. Individuals from the northern population grew and developed faster than individuals from the southern population at the highest temperatures (10 and 15°C), whereas the rates remained similar at the lowest temperature (5°C). Individuals of the northern population also became larger than the southern specimens at 10 and 15°C. Despite of increased growth, development rate and size of the northern animals compared to the southern, the specimens from the two populations lived equally long. 4. We argue that the higher growth and development rates in the northern individuals relative to the southern are due to a stronger selection for fast development at the northern site. The increase in rates at high rather than at low temperatures is explained by a large relative contribution of high temperatures to the total thermal sum of the soil microclimate.

• Coulson, Stephen J.; Leinaas, Hans Petter; Ims, Rolf Anker & Søvik, Guldborg (2000). Experimental manipulation of winter surface ice layer: The effects on a high arctic soil microarthropod community. Ecography. ISSN 0906-7590. 23, s. 299–306.
• Hertzberg, karine; Yoccoz, Nigel; Ims, Rolf Anker & Leinaas, Hans Petter (2000). The effects of spatial habitat configuration on recruitment, growth and population structure in arctic Collembola. Oecologia. ISSN 0029-8549. 124, s. 381–390.
• Gjøsæter, Jacob; Lekve, Kyrre; Stenseth, Nils Christian; Leinaas, Hans Petter; Christie, Hartvig & Dahl, Einar [Vis alle 11 forfattere av denne artikkelen] (2000). A long-term perspective on the Chrysochromulina bloom on the Norwegian Skagerrak coast 1988: a catastrophe or an innocent incident? Marine Ecology Progress Series. ISSN 0171-8630. 207, s. 201–218.
• Coulson, Stephen J.; Leinaas, Hans Petter; Ims, Rolf Anker & Søvik, Guldborg (2000). Experimental manipulation of the winter surface ice layer: the effects on a High Arctic soil microarthropod community. Ecography. ISSN 0906-7590. 23, s. 299–306. Vis sammendrag

  The effect of patch size on the tolerance of the soil microarthropod population to an experimentally induced environmental catastrophe, a thick surface ice layer, was studied at a high arctic site. Such an ice layer currently occurs infrequently; however, climatic change models suggest that the occurrence of such an ice layer is likely to increase in frequency. The experimental approach was a factorial design with two patch sizes, an icing treatment and controls. A thin layer of natural ice was present even in the controls and this was treated as a covariate in the analysis. The soil microarthropod fauna at the experimental site consisted of five species of Collembola and seven species of oribatid mites. The experimental surface ice layer reduced the total number of the soil microarthropods studied by 50%; however, mortality differed between mites and Collembola. Mites were very resistant and showed no significant change, while Collembola were more sensitive with a reduction of more than 50% in the ice treatment plots. The thin annual surface ice layer seemed to have an additional effect. This unexpected additional effect could play an important role in determing the extreme patchy distribution of arctic soil animals.

• Birkemoe, Tone & Leinaas, Hans Petter (2000). Effects of temperature on the development of an arctic Collembola (Hypogastrura tullbergi). Functional Ecology. ISSN 0269-8463. 14, s. 693–700. doi: 10.1046/j.1365-2435.2000.00478.x. Vis sammendrag

  1. Embryonic development, juvenile moulting and growth-rates, and maximum size of the arctic collembolan Hypogastrura tullbergi were investigated at 5, 10 and 15°C in laboratory experiments. The embryonic development was also investigated at 21°C. 2. The lower temperature threshold of the embryonic development (t0) was -1.3°C, possibly reflecting a slight cold adaptation. The temperature of maximum development rate exceeded 21°C. 3. Instar duration rate was linearly related to temperature. Growth per instar, however, was thermally dependent, giving an overall non-linear correlation between growth and temperature. This emphasises the importance of studying growth and moulting as separate processes in Collembola. 4. Development of genital area (number of hairs) over succeeding instars was affected by the temperature, suggesting that a higher proportion of individuals reached the adult stage in an earlier instar at 15 than at 10°C. 5. Contrary to the general pattern in ectotherms of increasing size at lower temperatures, adult H. tullbergi reached a larger maximum size at 15 than at 10°C. 6. No aspects of post embryonic development in H. tullbergi showed any signs of cold-adaptation, probably because it is more important to be able to efficiently utilise high temperatures frequently occurring in the micro habitat during sunny periods in summer.

• Leinaas, Hans Petter (1999). Collemboler i arktis. Tilpasninger til og konsekvenser av miljøvariasjoner. I Bengtson, Sven-Axel; Mehlum, Fridtjof & Severinsen, Torbjørn (Red.), Terrestrisk økologisk forskningsprogram på Svalbard. Svalbardtundraens Økologi. Norsk Polarinstitutt Meddelelser, Tromsø. ISSN 82-7666-139-4. s. 55–66.
• Leinaas, Hans Petter (1999). Spredning og kolonisering. Betydning av habitatheterogenitet og populasjonsdynamikk. I Bengtson, Sven-Axel; Mehlum, Fridtjof & Severinsen, Torbjørn (Red.), Terrestrisk økologisk forskningsprogram på Svalbard. Svalbardtundraens økologi. Norsk Polarinstitutt Meddelelser, Tromsø. ISSN 82-7666-139-4. s. 175–180.
• Leinaas, Hans Petter & Ambrose, William (1999). Decision between small and large prey: reduced energy acquisition by pre-migratory purple sandpipers, Calidris maritima, on Svalbard. Polar Biology. ISSN 0722-4060. 22, s. 264–270. Vis sammendrag

  On Svalbard, purple sandpipers forage on the shores when preparing autumn migration to the European continent after a period of food shortage on the tundra in summer. Their food choice was studied on a beach when they were faced with the choice between two abundant prey species; a small Collembola (springtail) and a much larger amphipod. In spite of several times higher gain of energy when foraging on amphipopds, the birds did not show distinct preference for either of the two prey species in this situation. Alternative explanations for this behaviour are discussed. We suggest that this could be a consequence of adaptations to their summer diet on Svalbard, when they rely on Collembola as food to a considerable extent. Higher variance in energy gain rate when foraging on amphipods might also be important. Collembolan densities high enough to trigger predation from birds occurred only on some days, with cloudy, calm weather. This, together with the possible existence of a dietary bottleneck may reduce the cost associated with the switching to Collembola.

• Leinaas, Hans Petter & Sømme, Lauritz Sverdrup (1999). Feature species: The springtail Hypogastrura tullbergi. Arctic Insect News. 10.
• Birkemoe, Tone & Leinaas, Hans Petter (1999). Reproductive biology of the Arctic collembolan Hypogastrura tullbergi. Ecography. ISSN 0906-7590. 22, s. 31–39. doi: 10.1111/j.1600-0587.1999.tb00452.x.
• Stien, A.; Leinaas, Hans Petter; Halvorsen, Odd & Christie, Hartvig (1998). Population dynamics of the Echinomermella matsi (Nematoda) - Strongylocentrotus droebachiensis (Echinoida) system: effects on host fecundity. Marine Ecology Progress Series. ISSN 0171-8630. 163, s. 193–201.

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• Sengupta, Sagnik; Leinaas, Hans Petter; van Gestel, Cornelis A.M. & Borgå, Katrine (2022). Interaction of neonicotinoid exposure and temperature on the life-history traits of the widely distributed Collembola Folsomia quadrioculata. .
• Konestabo, Heidi Sjursen; Birkemoe, Tone; Leinaas, Hans Petter; van Gestel, Cornelis A.M. & Borgå, Katrine (2020). How does a widely used neonicotinoid affect the soil fauna under natural field conditions? .
• Kristiansen, Silje Marie; Leinaas, Hans Petter; Herzke, Dorte; Hylland, Ketil; Gabrielsen, Geir W. & Harju, Mikael [Vis alle 7 forfattere av denne artikkelen] (2019). The Arctic tundra and its soil-dwelling springtails (Collembola) reflect nitrogen and contaminants biotransported by seabirds.
• Hylland, Ketil; Skei, Bjørn Borge; Gilmore, Erik Howard; Fredriksen, Lene; Keilen, Ellen Kristine & Kristiansen, Silje Marie [Vis alle 11 forfattere av denne artikkelen] (2018). Er det en sammenheng mellom miljøgift-eksponering og DNA-skade i spretthaler, hoppekreps, blåskjell, fisk, fugl og isbjørn?
• Bengtsson, Jan; Leinaas, Hans Petter; Janion, Charlene & Chown, Steven L. (2014). Effect of plant species on springtail diversity and species composition in remnant renosterveld patches of the Fynbos biome, South Africa.
• Gundersen, Håkon A Holm; Thaulow, Christian & Leinaas, Hans Petter (2013). Springtail Cuticles as a Model for Biomimetic Superhydrophobic Surfaces.
• Schnug, Lisbeth; Chen, Kun; Sverdrup, Line Emilie; Hylland, Ketil & Leinaas, Hans Petter (2013). Ecotoxicological studies on Collembola.
• Sengupta, Sagnik & Leinaas, Hans Petter (2012). Adaptations to contrasting environments in Folsomia quadrioculata: acclimation effects on hatchling size and egg developmental arrest.
• Janion, Charlene; Bengtsson, Jan; Leinaas, Hans Petter; Deharveng, Louis & Chown, Steven L. (2012). Collembola diversity in the fynbos of South Africa: the effects of fire.
• Leinaas, Hans Petter (2012). Collembola as model organisms in ecological research; potential for integrative approaches to environmental change effects.
• Hylland, Ketil ; Skei, Bjørn Borge; Nerland, Inger Lise; Leinaas, Hans Petter & Brunborg, Gunnar (2011). Using comet with blood cells from terrestrial and aquatic organisms.
• Bengtsson, Jan & Leinaas, Hans Petter (2011). Springtail communities and plant decomposition in renosterveld, South Africa. How (some)plants can favour an invasive springtail, or Where has all the litter gone?
• Bengtsson, Jan; Leinaas, Hans Petter; Janion, Charlene & Chown, Steven L. (2011). Springtail diversity and plant decomposition in the Fynbos Biome, South Africa.
• Bengtsson, Jan; Janion, Charlene; Chown, Steven L. & Leinaas, Hans Petter (2011). Springtail diversity and plant decomposition in the fynbos biome, South Africa.
• Janion, Charlene; Bengtsson, Jan; Leinaas, Hans Petter & Chown, Steven L. (2010). Landscape conversion and soil biodiversity in the fynbos biome: springtails as exemplars.
• Leinaas, Hans Petter & Chown, Steven L. (2010). Springtail responses to changing environments.
• Janion, Charlene; Bengtsson, Jan; Leinaas, Hans Petter & Chown, Steven L. (2009). Landscape conversion and soil biodiversity in the Fynbos: springtails as exemplars.
• Chown, Steven L. & Leinaas, Hans Petter (2009). Springtail responses to a changing environment.
• Leinaas, Hans Petter & Chown, Steven L. (2007). Environmental Responses in Collembola (Springtails): Implications for climate change.
• Leinaas, Hans Petter (2006). Stoichiometry for the collembologist, or time constraints, growth rate and response on food nutrient elements in arctic Collembola.
• Janion, Charlene; Chown, Steven L. & Leinaas, Hans Petter (2006). The effect of temperature on the egg development of Collembola from Marion Island: indigenous vs. invasive species.
• Hasle, Gunnar; Mehl, Reidar; Bjune, Gunnar & Leinaas, Hans Petter (2004). : Transport of ticks by migratory birds.
• Hasle, Gunnar; Mehl, Reidar; Bjune, Gunnar & Leinaas, Hans Petter (2004). Transport of ticks by migratory birds in Norway.
• Leinaas, Hans Petter (2004). Dynamics of Collembola in a landscape of small habitat patches; an experimental model system approach.
• Leinaas, Hans Petter (2004). Temperature adaptation in Arctic Collembola; thermal reaction norms of egg development.
• Hagen, Snorre B.; Leinaas, Hans Petter & Lampe, Helene Marie (2003). Response of great tits (Parus major) to small tortoiseshells (Agelais urticae) in feeding trials; evidence of aposematism. Ecological Entomology. ISSN 0307-6946. 28, s. 503–509.
• Leinaas, Hans Petter (2002). Habitat heterogeneity and climatic change; Collembola as model organisms in studies on adaptation to and consequences of variations in space and time.
• Coulson, Stephen J. & Leinaas, Hans Petter (1999). Intergrated field and fytotron studies of the interaction of spatial and temporal environmental heterogeneity on the population dynamics of Arctic Collembola species assemblages.
• Leinaas, Hans Petter (1999). Collembola in variable arctic environments. Adaptations to and consequences of changes in time and space.
• Leinaas, Hans Petter (1999). The role of spatial and temporal environmental variation in shaping diversity and dynamics in Collembola species assemblages.

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