| 1. |
- Boratynski, Zbyszek, et al.
(author)
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Increased radiation from Chernobyl decreases the expression of red colouration in natural populations of bank voles (Myodes glareolus)
- 2014
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 4, s. 7141-
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Journal article (peer-reviewed)abstract
- Pheomelanin is a pink to red version of melanin pigment deposited in skin and hair. Due to its bright colour, pheomelanin plays a crucial function in signalling, in particular sexual signalling. However, production of pheomelanin, as opposed to its dark alternative, eumelanin, bears costs in terms of consumption of antioxidants important for protection of DNA against naturally produced reactive oxidative species. Therefore, decreased expression of pheomelanin is expected in organisms exposed to severe oxidative stress such as that caused by exposure to chronic ionizing radiation. We tested if variable exposure to radiation among natural populations of bank voles Myodes glareolus in Chernobyl affected expression of red colouration in their dorsal fur. The relative redness of dorsal fur was positively correlated with weight, but also negatively correlated with the level of background radiation. These results suggest that the development of the natural red colouration in adult bank voles is affected by ionizing background radiation, and potentially causing elevated levels of oxidative stress. Reduced production of pheomelanin allows more antioxidants to mitigate the oxidative stress caused by radiation. However, changing natural animal colouration for physiological reasons can have ecological costs, if e.g. it causes mismatch with habitat colouration and conspicuousness for predators.
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| 2. |
- Eigmüller, Philipp, et al.
(author)
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AN M DWARF COMPANION TO AN F-TYPE STAR IN A YOUNG MAIN-SEQUENCE BINARY
- 2016
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In: Astronomical Journal. - : American Astronomical Society. - 1538-3881 .- 0004-6256. ; 151:3
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Journal article (peer-reviewed)abstract
- Only a few well characterized very low-mass M dwarfs are known today. Our understanding of M dwarfs is vital as these are the most common stars in our solar neighborhood. We aim to characterize the properties of a rare F+dM stellar system for a better understanding of the low-mass end of the Hertzsprung-Russel diagram. We used photometric light curves and radial velocity follow-up measurements to study the binary. Spectroscopic analysis was used in combination with isochrone fitting to characterize the primary star. The primary star is an early F-type main-sequence star with a mass of (1.493 +/- 0.073) M-circle dot and a radius of (1.474 +/- 0.040) R-circle dot. The companion is an M dwarf with a mass of (0.188 +/- 0.014) M-circle dot and a radius of (0.234 +/- 0.009) R-circle dot. The orbital period is (1.35121 +/- 0.00001) days. The secondary star is among the lowest-mass M dwarfs known to date. The binary has not reached a 1: 1 spin-orbit synchronization. This indicates a young main-sequence binary with an age below similar to 250 Myr. The mass-radius relation of both components are in agreement with this finding.
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| 3. |
- Emami, S. Noushin, et al.
(author)
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A key malaria metabolite modulates vector blood seeking, feeding, and susceptibility to infection
- 2017
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In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 355:6329
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Journal article (peer-reviewed)abstract
- Malaria infection renders humans more attractive to Anopheles gambiae sensu lato mosquitoes than uninfected people. The mechanisms remain unknown. We found that an isoprenoid precursor produced by Plasmodium falciparum, (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMBPP), affects A. gambiae s. l. blood meal seeking and feeding behaviors as well as susceptibility to infection. HMBPP acts indirectly by triggering human red blood cells to increase the release of CO2, aldehydes, and monoterpenes, which together enhance vector attraction and stimulate vector feeding. When offered in a blood meal, HMBPP modulates neural, antimalarial, and oogenic gene transcription without affecting mosquito survival or fecundity; in a P. falciparum-infected blood meal, sporogony is increased.
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| 4. |
- Friberg, Magne, et al.
(author)
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Autumn mass change and winter mass loss differ between migratory and nonmigratory butterflies
- 2023
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In: Animal Behaviour. - 0003-3472 .- 1095-8282. ; 204, s. 67-75
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Journal article (peer-reviewed)abstract
- Poikilotherms have two major alternative strategies to deal with the inhospitable conditions of temperate winters: hibernation or migration. The vast majority of insects spend winter in a speciesspecific diapause resting stage, while others remain reproductively active after having migrated to more hospitable environments in the autumn. The butterfly clade Nymphalini offers an interesting possibility for comparisons among species adopting different strategies. Whereas most genera in this clade have evolved adult diapause, species in the genus Vanessa engage in an annual multigeneration migration cycle, leaving northern latitudes during autumn. Here, we compared two species of diapausing Aglais butterflies, A. io and A. urtica, two species of the migratory genus Vanessa, V. atalanta and V. cardui, and two morphs of Polygonia c-album, the diapausing winter morph and the direct developing hutchinsoni morph. We tested how these different species differ in resource acquisition strategy during early adult life, how the acquisition of resources affects survival in cold winter conditions and how A. io, Aglais urticae and V. atalanta differ in resting metabolism under cold conditions. The butterflies set for adult diapause (1) acquired more mass during early adult life and (2) lost less mass and had a lower resting metabolism under cold conditions. In addition, (3) the life span under cold conditions was positively related to the weight increase during early adult life in the diapausing species, but not in the migratory species. Our laboratory results demonstrate how different developmental pathways, such as diapause or direct development, can be studied by measuring mass change in living butterflies. Our expectation that migratory species would increase in mass like species set for overwintering were not met, perhaps because such studies should ideally be performed under natural conditions. (c) 2023 The Author(s). Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour. This is an open access article under the CC BY license (http://creativecommons.org/licenses/ by/4.0/).
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| 5. |
- Greiser, Caroline, 1987-, et al.
(author)
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Microclimatic variation affects developmental phenology, synchrony and voltinism in an insect population
- 2022
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In: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 36:12, s. 3036-3048
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Journal article (peer-reviewed)abstract
- Temperature influences the rate of most biological processes. Nonlinearities in the thermal reaction norms of such processes complicate intuitive predictions of how ectothermic organisms respond to naturally fluctuating temperatures, and by extension, to climate warming. Additionally, organisms developing close to the ground experience a highly variable microclimate landscape that often is poorly captured by coarse standard climate data.Using a butterfly population in central Sweden as a model, we quantified the consequences of small-scale temperature variation on phenology, emergence synchrony and number of annual reproductive cycles (voltinism). By combining empirical microclimate and thermal performance data, we project development of individual green-veined white butterflies (Pieris napi) across 110 sites in an exceptionally high-resolved natural microclimate landscape.We demonstrate that differences among microclimates just meters apart can have large impacts on the rate of development and emergence synchrony of neighbouring butterflies. However, when considering the full development from egg to adult, these temporal differences were reduced in some scenarios, due to negative correlations in development times among life stages. The negative correlations were caused by temperatures at some sites beginning to exceed the optimum for development as the season progressed. Indeed, which sites were optimal for fast development could change across the lifetimes of individual butterflies, that is, ‘fast’ sites could become ‘slow’ sites. Thus, from a thermal point of view, there seem to be no consistently optimal microsites. Importantly, the fast sites were not always the warmest sites. We showed that such unintuitive effects could play an important role in the regulation of phenological synchrony and voltinism in insects, as most sites consistently favoured two generations. The results were generally robust across years and three different egg-laying dates.Using high-resolved empirical climate data on organism-relevant temporal and spatial scales and considering nonlinear responses to temperature, we demonstrated the large and unintuitive population-level consequences of locally and temporarily high temperatures. We suggest to—whenever possible—incorporate species- and life stage-specific nonlinear responses to temperature when studying the effects of natural microclimate variation and climate change on organisms.
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| 6. |
- Haage, Mathias, et al.
(author)
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Increasing Robotic Machining Accuracy Using Offline Compensation Based on Joint-Motion Simulation
- 2014
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In: [Host publication title missing]. - 9783800736010
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Conference paper (peer-reviewed)abstract
- In this paper an approach for improving robot machining accuracy through simulation-assisted path planning within Computer-Aided Manufacturing (CAM) tools is investigated. The method comprises modeling of dynamic robot behaviour under influence of process forces and a subsequent simulation of the robot motion which results in an offline prediction of deflection errors during the machining task. The error prediction performed inside the CAM-tool is utilised to already offline apply compensations to the planned tool-path for the robot. The whole computer-tool chain has been implemented and integrated within a commercial CAM-software. The focus of this paper is to describe the system architecture and do initial validation and analysis of the proposed method and experimental results.
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| 7. |
- Harvey, Jeffrey A., et al.
(author)
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Scientists' warning on climate change and insects
- 2023
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In: Ecological Monographs. - : Wiley. - 0012-9615 .- 1557-7015. ; 93:1
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Research review (peer-reviewed)abstract
- Climate warming is considered to be among the most serious of anthropogenic stresses to the environment, because it not only has direct effects on biodiversity, but it also exacerbates the harmful effects of other human-mediated threats. The associated consequences are potentially severe, particularly in terms of threats to species preservation, as well as in the preservation of an array of ecosystem services provided by biodiversity. Among the most affected groups of animals are insects—central components of many ecosystems—for which climate change has pervasive effects from individuals to communities. In this contribution to the scientists' warning series, we summarize the effect of the gradual global surface temperature increase on insects, in terms of physiology, behavior, phenology, distribution, and species interactions, as well as the effect of increased frequency and duration of extreme events such as hot and cold spells, fires, droughts, and floods on these parameters. We warn that, if no action is taken to better understand and reduce the action of climate change on insects, we will drastically reduce our ability to build a sustainable future based on healthy, functional ecosystems. We discuss perspectives on relevant ways to conserve insects in the face of climate change, and we offer several key recommendations on management approaches that can be adopted, on policies that should be pursued, and on the involvement of the general public in the protection effort.
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| 8. |
- Hedlund, Johanna, et al.
(author)
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New records of the Paleotropical migrant Hemianax ephippiger in the Caribbean and a review of its status in the Neotropics
- 2020
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In: International Journal of Odonatology. - : Worldwide Dragonfly Association. - 1388-7890 .- 2159-6719. ; 23:4, s. 315-325
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Journal article (peer-reviewed)abstract
- Tropical America is currently experiencing the establishment of a new apex insect predator, the Paleotropical dragonfly Hemianax ephippiger (Odonata: Aeshnidae). H. ephippiger is migratory and is suggested to have colonised the eastern Neotropics by chance Trans-Atlantic displacement. We report the discovery of H. ephippiger at three new locations in the Caribbean, the islands of Bonaire, Isla de Coche (Venezuela), and Martinique, and we review its reported distribution across the Neotropics. We discuss the establishment of H. ephippiger as a new apex insect predator in the Americas, both in terms of ecological implications and the possible provision of ecosystem services. We also provide an additional new species record for Bonaire, Pantala hymenaea (Odonata: Libellulidae).
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| 9. |
- Hedlund, Johanna S.U., et al.
(author)
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Unraveling the World’s Longest Non-stop Migration : The Indian Ocean Crossing of the Globe Skimmer Dragonfly
- 2021
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In: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 9
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Journal article (peer-reviewed)abstract
- Insect migration redistributes enormous quantities of biomass, nutrients and species globally. A subset of insect migrants perform extreme long-distance journeys, requiring specialized morphological, physiological and behavioral adaptations. The migratory globe skimmer dragonfly (Pantala flavescens) is hypothesized to migrate from India across the Indian Ocean to East Africa in the autumn, with a subsequent generation thought to return to India from East Africa the following spring. Using an energetic flight model and wind trajectory analysis, we evaluate the dynamics of this proposed transoceanic migration, which is considered to be the longest regular non-stop migratory flight when accounting for body size. The energetic flight model suggests that a mixed strategy of gliding and active flapping would allow a globe skimmer to stay airborne for up to 230–286 h, assuming that the metabolic rate of gliding flight is close to that of resting. If engaged in continuous active flapping flight only, the flight time is severely reduced to ∼4 h. Relying only on self-powered flight (combining active flapping and gliding), a globe skimmer could cross the Indian Ocean, but the migration would have to occur where the ocean crossing is shortest, at an exceptionally fast gliding speed and with little headwind. Consequently, we deem this scenario unlikely and suggest that wind assistance is essential for the crossing. The wind trajectory analysis reveals intra- and inter-seasonal differences in availability of favorable tailwinds, with only 15.2% of simulated migration trajectories successfully reaching land in autumn but 40.9% in spring, taking on average 127 and 55 h respectively. Thus, there is a pronounced requirement on dragonflies to be able to select favorable winds, especially in autumn. In conclusion, a multi-generational, migratory circuit of the Indian Ocean by the globe skimmer is shown to be achievable, provided that advanced adaptations in physiological endurance, behavior and wind selection ability are present. Given that migration over the Indian Ocean would be heavily dependent on the assistance of favorable winds, occurring during a relatively narrow time window, the proposed flyway is potentially susceptible to disruption, if wind system patterns were to be affected by climatic change.
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| 10. |
- Isabelle, Siemers, et al.
(author)
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Predictable local adaptation in butterfly photoperiodism but not thermal performance along a latitudinal cline
-
Other publication (other academic/artistic)abstract
- In seasonal environments, organisms must synchronize their life cycles to conditions favorable for growth and reproduction. Because season length varies geographically, local adaptation should arise in traits that regulate phenological responses. Geographic photoperiodism clines are well-known, but comparable studies on thermal performance are equivocal and often overlook non-linear responses. Therefore, we examined local adaptation in plastic responses to both photoperiod and temperature along a 752 km latitudinal cline, by comparing four Swedish populations of the butterfly Pieris napi. Using a common garden design, we estimated (1) photoperiod response curves for diapause induction and (2) thermal performance curves for development and growth rates. We show that differences in photoperiodism follow the expected geographical pattern, where diapause is induced at longer daylengths in northern populations (where growth seasons are short and summer days long). However, population differences in thermal performance curves were small and seemingly idiosyncratic, without clear clinal patterns. Photoperiodic responses appear to evolve more readily than thermal responses, indicating that photoperiodism is the key driver of local life cycle synchronization.
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