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  • 1. Abalaka, J. L.
    et al.
    Ottosson, Ulf
    Tende, Talatu
    Larson, Keith W.
    Rock Firefinch Lagonosticta sanguinodorsalis in the Mandara Mountains, north-east Nigeria: a new subspecies?2010In: African Bird Club Bulletin, ISSN 1352-481X, Vol. 17, no 2, 210-211 p.Article in journal (Refereed)
    Abstract [fr]

    L’Amarante des rochers Lagonosticta sanguinodorsalis dans les Monts Mandara, Nigeria du sud-est: une nouvelle sous-espèce ? Nous fournissons une description d’un mâle et d’une femelle, ainsi que desphotos d’un mâle, d’un amarante capturé dans les Monts Mandara, au nord-est du Nigeria. Le plumage et le cri de cet amarante sont identiques à ceux de l’Amarante des rochers Lagonosticta sanguinodorsalis, une espèce précédemment rapportée de la zone, excepté que le mâle n’a pas la couronne grise typique de l’espèce. Des travaux supplémentaires sur le terrain sont nécessaires pour déterminer s’il agit d’un individu aberrant ou d’une population de l’Amarante des rochers morphologiquement distincte.

  • 2.
    Abreu-Vieira, Gustavo
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Regulation and measurement of brown adipose tissue blood flow2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Brown adipose tissue (BAT) is an organ specialized in macromolecule combustion in order to produce heat. Because of its high capacity to dissipate energy, it is currently among the best hopes for future treatments of obesity and diabetes. BAT is permeated by a vast capillary network that delivers blood rich in oxygen and nutrients to supply the high metabolic needs of the tissue. At the same time, metabolites, carbon dioxide and warm blood are drained back into systemic circulation. Blood flow is in fact a limiting factor for thermogenesis. Therefore, understanding BAT blood flow regulation is a crucial step for describing the tissue function. This thesis aims to summarize anatomical descriptions, to discuss the methodological evolution of the field, and to synthetize what we have learned about mechanistic regulation of BAT blood flow during the last half century. Manuscript I introduces a new method (high-resolution laser-doppler imaging) for the measurement of BAT blood flow, and gives mechanistic insights about its physiological regulation. Manuscript II focuses on the influence of bombesin receptor subtype-3 on the neurological control of body temperature and thermogenesis.

  • 3.
    Ackefors, Hans
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    The evolution of a worldwide shrimp industry2009In: World Aquaculture, ISSN 1041-5602, Vol. 40, no 3, 46-55 p.Article in journal (Refereed)
  • 4.
    Ageheim, Sofia
    et al.
    Executive, Länsstyrelser, Länsstyrelsen Gävleborg.
    Nordin, Hans
    Executive, Länsstyrelser, Länsstyrelsen Gävleborg.
    Sundin, Sara
    Executive, Länsstyrelser, Länsstyrelsen Gävleborg.
    Inventering av stora rovdjur i Gävleborgs län 2014-20152015Report (Other academic)
    Abstract [sv]

     

    Länsstyrelsen ansvarar för att årliga rovdjursinventeringar genomförs i Gävleborgs län. Syftet är att

    övervaka rovdjursstammarnas storlek, utbredning, genetiska status och hur stammarna utvecklas

    över tiden.

     

    I den här rapporten redovisas resultaten från inventeringar av lodjur, varg, järv och kungsörn, samt

    länsstyrelsens bedömning av förekomsten av björn i Gävleborg under inventeringssäsongen

    2014/2015.

     

    Vid lodjursinventeringen 2014/2015 kvalitetssäkrades 15 familjegrupper, det vill säga 15 honor som

    fött ungar 2014. Lodjursstammen i Gävleborg kan därmed uppskattas till cirka 83 individer vintern

    2014/2015. Fyra av familjegrupperna delades med angränsande län.

     

    Gävleborg berördes av tio vargrevir vintern 2014/2015: Prästskogen/Haverö, Naggen, Kukumäki,

    Sjösveden, Tandsjön, Lingbo, Åmot/Ockelbo, Bondskog, Björnås och Glamsen. I sju av reviren

    bekräftades att föryngring skett våren 2014. Sex av reviren delades med andra län. Det innebär att

    Gävleborg anses ha haft 4,7 familjegrupper vintern 2014/2015, enligt Viltskadecenters fördelning.

    Vargarna i Korsåreviret, som tidigare delades mellan Gävleborg och Dalarna, har denna säsong vistats

    väster om länsgränsen och har inte spårats i Gävleborg. Tandsjö-reviret försvann under

    inventeringssäsongen genom skyddsjakt i februari 2015.

     

    Ingen inventering av björn har genomförts denna säsong. Länsstyrelsen bedömer att björnstammens

    storlek och spridning i länet sannolikt överensstämmer med resultatet från 2012 års spillningsinventering. Björnstammen uppskattades då till cirka 380 individer i Gävleborgs län.

     

    En riktad järvinventering har för första gången på många år genomförts i Gävleborgs län vintern

    2014/2015. Med hjälp av fotostationer har bilder på järv erhållits på flera ställen i hela norra delen av

    Gävleborg och en föryngring 2014 har kvalitetssäkrats.

     

    Vid inventeringen av kungsörn i Gävleborg 2014 konstaterades totalt 25 revir, varav 8 hade lyckade

    häckningar och 3 av dessa var dubbelkullar, det vill säga kullar med två ungar. Storleken på länets

    fasta kungsörnspopulation 2014 uppskattas till 50-65 individer.

     

    Inventeringarna av lo, järv och varg utfördes av länsstyrelsens personal, medan kungsörn

    inventerades av Kungsörnsgruppen Gävleborg på uppdrag av länsstyrelsen. Allmänhetens

    rapportering av rovdjursobservationer har varit till stor hjälp i arbetet med att göra så bra

    inventeringar som möjligt utifrån de resurser som finns.

  • 5. Agianian, Bogos
    et al.
    Lesch, Christine
    Loseva, Olga
    Dushay, Mitchell S.
    Södertörn University, School of Life Sciences. Uppsala University.
    Preliminary characterization of hemolymph coagulation in Anopheles gambiae larvae2007In: Developmental and Comparative Immunology, ISSN 0145-305X, E-ISSN 1879-0089, Vol. 31, no 9, 879-888 p.Article in journal (Refereed)
    Abstract [en]

    Hemolymph coagulation is a first response to injury, impeding infection, and ending bleeding. Little is known about its molecular basis in insects, but clotting factors have been identified in the fruit fly Drosophila melanogaster. Here, we have begun to study coagulation in the aquatic larvae of the malaria vector mosquito Anopheles gambiae using methods developed for Drosophila. A delicate clot was seen by light microscopy, and pullout and proteomic analysis identified phenoloxidase and apolipophorin-I as major candidate clotting factors. Electron microscopic analysis confirmed clot formation and revealed it contains fine molecular sheets, most likely a result of lipophorin assembly. Phenoloxidase appears to be more critical in clot formation in Anopheles than in Drosophila. The Anopheles larval clot thus differs in formation, structure, and composition from the clot in Drosophila, confirming the need to study coagulation in different insect species to learn more about its evolution and adaptation to different lifestyles.

  • 6.
    Agnvall, Beatrix
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Bélteky, Johan
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Brain size is reduced by selectionfor tameness in Red Junglefowl–correlated effects in vital organs2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, 3306Article in journal (Refereed)
    Abstract [en]

    During domestication animals have undergone changes in size of brain and other vital organs. We hypothesize that this could be a correlated effect to increased tameness. Red Junglefowl (ancestors of domestic chickens) were selected for divergent levels of fear of humans for five generations. The parental (P0) and the fifth selected generation (S5) were culled when 48–54 weeks old and the brains were weighed before being divided into telencephalon, cerebellum, mid brain and optic lobes. Each single brain part as well as the liver, spleen, heart and testicles were also weighed. Brains of S5 birds with high fear scores (S5 high) were heavier both in absolute terms and when corrected for body weight. The relative weight of telencephalon (% of brain weight) was significantly higher in S5 high and relative weight of cerebellum was lower. Heart, liver, testes and spleen were all relatively heavier (% of body weight) in S5 high. Hence, selection for tameness has changed the size of the brain and other vital organs in this population and may have driven the domesticated phenotype as a correlated response.

  • 7.
    Agnvall, Beatrix
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Katajamaa, Rebecca
    Linköping University, Department of Physics, Chemistry and Biology, Biology.
    Altimiras, Jordi
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Jensen, Per
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, Faculty of Science & Engineering.
    Is domestication driven by reduced fear of humans? Boldness, metabolism and serotonin levels in divergently selected red junglefowl (Gallus gallus)2015In: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 11, no 9, 20150509Article in journal (Refereed)
    Abstract [en]

    Domesticated animals tend to develop a coherent set of phenotypic traits. Tameness could be a central underlying factor driving this, and we therefore selected red junglefowl, ancestors of all domestic chickens, for high or low fear of humans during six generations. We measured basal metabolic rate (BMR), feed efficiency, boldness in a novel object (NO) test, corticosterone reactivity and basal serotonin levels (related to fearfulness) in birds from the fifth and sixth generation of the high- and low-fear lines, respectively (44-48 individuals). Corticosterone response to physical restraint did not differ between selection lines. However, BMR was higher in low-fear birds, as was feed efficiency. Low-fear males had higher plasma levels of serotonin and both low-fear males and females were bolder in an NO test. The results show that many aspects of the domesticated phenotype may have developed as correlated responses to reduced fear of humans, an essential trait for successful domestication.

  • 8. Aguirre, A. A.
    et al.
    Angerbjörn, A.
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Tannerfeldt, Magnus
    Stockholm University, Faculty of Science, Department of Zoology.
    Mörner, T.
    Health evaluation of arctic fox (Alopex lagopus) cubs in Sweden2000In: Journal of Zoo and Wildlife Medicine, Vol. 31, no 1, 36-40 p.Article in journal (Refereed)
    Abstract [en]

    Hematologic. serum biochemistry, and serum cortisol reference ranges were established and tonsil/rectal bacterial and fecal parasite examinations were performed on 21 wild arctic fox (Alopex lagopus) cubs during July 1996. Several of the hematologic and serum biochemistry values fell within normal ranges for other wild canids or domestic dogs of the same age class. Serum alanine transaminase and creatine phosphokinase values were significantly higher in the youngest cubs. Proteus vulgaris and Escherichia coli were isolated from both tonsilar and rectal swabs of several cubs in all dens. The most common gastrointestinal parasite ova were Toxascaris leonina (59%), Isospora spp. (52%), Uncinaria stenocephala (33%), and Capillaria spp. (26%). Prevalence of T. leonina differed significantly between dens and between age groups. Hematologic and serum biochemistry values and degree of parasitism may be indicators of health, stress, and nutritional status of arctic foxes.

  • 9. Aguirre, A. Alonso
    et al.
    Principe, B.
    Tannerfeldt, Magnus
    Stockholm University, Faculty of Science, Department of Zoology.
    Angerbjörn, Anders
    Stockholm University, Faculty of Science, Department of Zoology.
    Mörner, Torsten
    Field anesthesia of wild arctic fox (Alopex lagopus) cubs in the Swedish lapland using medetomidine-ketamine-atipamezole2000In: Journal of Zoo and Wildlife Medicine, Vol. 31, no 2, 244-246 p.Article in journal (Refereed)
    Abstract [en]

    A safe and effective anesthetic regime for use in arctic fox (Alopex lagopus) cubs was developed. During July 1996, six free-ranging 6-8-wk-old cubs were captured near their den in Vindelfjallen Nature Reserve, Sweden. Medetomidine and ketamine HCl, followed by atipamezole, were selected for the anesthetic trial because of the well-documented safety and efficacy of this drug combination in a broad range of species. The dosage regimen used was 50 mu g/kg medetomidine combined with 2.5 mg/kg ketamine followed by reversal with 250 mu g/kg atipamezole. induction was rapid, with a mean induction time of 1 min and 32 sec (range: 58-150 sec). The cubs were anesthetized for a mean time of 18 +/- 5 min (range: 13-25 min). Serially recorded heart rate, respiratory rate, temperature, and pulse oximetry were stable throughout the anesthetic period for all cubs. Anesthetic depth was suitable for safe handling and minor clinical procedures, including venipuncture. Following atipamezole, all cubs were standing within 12 +/- 7 min (range: 5-24 min) and fully recovered at 27 +/- 5 min (range: 19-36 min). This information will be useful for future captive breeding and management programs involving the endangered arctic fox.

  • 10. Agustí, J.
    et al.
    Werdelin, LarsSwedish Museum of Natural History, Department of Paleobiology.
    Influence of climate on faunal evolution in the Quaternary of Europe1995Collection (editor) (Refereed)
  • 11. Ah-King, Malin
    Phylogenetic analyses of parental care evolution2003Doctoral thesis, comprehensive summary (Other academic)
  • 12.
    Ahlen, Ingemar
    Executive, Universitet, Swedish University of Agricultural Sciences, Sveriges lantbruksuniversitet, skoglig resurshållning.
    Skydd av biotoper för bevarande av vitryggig hackspett i nedre Dalälven1976Report (Other academic)
    Abstract [sv]

    Den vitryggiga hackspetten Dendrocopos leucotos, som ursprungligen förekommit över nästan hela landet, har under de senaste hundra åren blivit allt sällsyntare och finns nu, förutom i några spridda förekomster av enstaka par eller ensamma fåglar, i landet endast kvar med en fast population i nedre Dalälvsområdet mellan Avesta och Älvkarleby.

    De hotade hackspettarterna har sedan 1974 varit föremål för ekologisk forskning och inventeringsarbete. I bilagda ”information om projekt hackspettars ekologi” 1976-01-18 redovisas projektets syfte och kortfattad redogörelse för arbetet under 1975 ges. Hänvisning kan också göras till tidskriften Vår Fågelvärlds första nummer 1976 där resultat av 1973 års riksinventering av gråspett och vitryggig hackspett redovisas.

  • 13.
    Ahnesjo, Ingrid
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolutionary Biology.
    Kvarnemo, C
    Merilaita, S
    Using potential reproductive rates to predict mating competition among individuals qualified to mate2001In: BEHAVIORAL ECOLOGY, ISSN 1045-2249, Vol. 12, no 4, 397-401 p.Article in journal (Refereed)
    Abstract [en]

    The potential reproductive rate (PRR), which is the offspring production per unit time each sex would achieve if unconstrained by mate availability, often differs between the sexes. An increasing sexual difference in PRR predicts an intensified mating com

  • 14. Ahola, Virpi
    et al.
    Lehtonen, Rainer
    Somervuo, Panu
    Salmela, Leena
    Koskinen, Patrik
    Rastas, Pasi
    Valimaki, Niko
    Paulin, Lars
    Kvist, Jouni
    Wahlberg, Niklas
    Tanskanen, Jaakko
    Hornett, Emily A.
    Ferguson, Laura C.
    Luo, Shiqi
    Cao, Zijuan
    de Jong, Maaike A.
    Duplouy, Anne
    Smolander, Olli-Pekka
    Vogel, Heiko
    McCoy, Rajiv C.
    Qian, Kui
    Chong, Wong Swee
    Zhang, Qin
    Ahmad, Freed
    Haukka, Jani K.
    Joshi, Aruj
    Salojarvi, Jarkko
    Wheat, Christopher W.
    Stockholm University, Faculty of Science, Department of Zoology.
    Grosse-Wilde, Ewald
    Hughes, Daniel
    Katainen, Riku
    Pitkanen, Esa
    Ylinen, Johannes
    Waterhouse, Robert M.
    Turunen, Mikko
    Vaharautio, Anna
    Ojanen, Sami P.
    Schulman, Alan H.
    Taipale, Minna
    Lawson, Daniel
    Ukkonen, Esko
    Makinen, Veli
    Goldsmith, Marian R.
    Holm, Liisa
    Auvinen, Petri
    Frilander, Mikko J.
    Hanski, Ilkka
    The Glanville fritillary genome retains an ancient karyotype and reveals selective chromosomal fusions in Lepidoptera2014In: Nature Communications, ISSN 2041-1723, Vol. 5, 4737- p.Article in journal (Refereed)
    Abstract [en]

    Previous studies have reported that chromosome synteny in Lepidoptera has been well conserved, yet the number of haploid chromosomes varies widely from 5 to 223. Here we report the genome (393 Mb) of the Glanville fritillary butterfly (Melitaea cinxia; Nymphalidae), a widely recognized model species in metapopulation biology and eco-evolutionary research, which has the putative ancestral karyotype of n = 31. Using a phylogenetic analyses of Nymphalidae and of other Lepidoptera, combined with orthologue-level comparisons of chromosomes, we conclude that the ancestral lepidopteran karyotype has been n = 31 for at least 140 My. We show that fusion chromosomes have retained the ancestral chromosome segments and very few rearrangements have occurred across the fusion sites. The same, shortest ancestral chromosomes have independently participated in fusion events in species with smaller karyotypes. The short chromosomes have higher rearrangement rate than long ones. These characteristics highlight distinctive features of the evolutionary dynamics of butterflies and moths.

  • 15.
    Alatalo, Rauno V
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Lundberg, Arne
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Sundberg, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Can Female Preference Explain Sexual Dichromatism In The Pied Flycatcher, Ficedula-Hypoleuca1990In: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 39, 244-252 p.Article in journal (Refereed)
    Abstract [en]

    How important female choice is for the evolution of male secondary sexual characteristics is controversial. Two field and one laboratory experiment, using the pied flycatcher, were performed to test the female choice aspect of sexual selection. In addition, non-manipulative data from 5 years are presented. The observational data suggest a slight preference for dark males by females but in field experiments in which males had territories at random sites (i.e. they did not choose a territory) or the colour of concurrently arriving males was altered, there was no preference for darker ones. Similarly, oestradiol-treated females did not prefer black or brown males in the laboratory. Thus, there is little support for the idea that female choice has been an important mechanism in the evolution of sexual dichromatism in the pied flycatcher.

  • 16.
    Alfredsson, Jessica
    Umeå University, Faculty of Social Sciences, Department of Psychology.
    INNOVATIVE TOOL-MODIFICATIONS AND TOOL SELECTIVITY IN NEW CALEDONIAN CROWS (CORVUS MONEDULOIDES)2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Tool-use and tool-manufacture are thought to require high cognitive skills and have been considered as an exclusive attribute to primates. Recent observations of New Caledonian crows (NCCs) challenge this assumption. In this study 13 NCCs were tested with two different tool production tasks. The NCC either had to straighten a hook or bend a stick to retrieve food from two different kinds of tree trunks. The result showed that 3/5 birds bent sticks and used them to retrieve food and 1/5 birds straightened hooks to retrieve food. The birds managed to solve both tasks but not the birds in the control group. This indicates that NCC's tool making is a flexible innovative act and not just an innate predisposition to bend flexible material. This finding is interesting given that recent studies on human children show that below 8 years of age children fail in similar innovative tool making tasks.

  • 17.
    Allander, Klas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Sundberg, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology.
    Temporal variation and reliability of blood parasite levels in captive Yellowhammer males Emberiza citrinella1997In: Journal of Avian Biology, ISSN 0908-8857, E-ISSN 1600-048X, Vol. 28, no 4, 325-330 p.Article in journal (Refereed)
    Abstract [en]

    The temporal variation of blood parasites in captive Yellowhammer males was studied in order to investigate possible costs of parasites. Birds were caught in the wild in early April and kept in aviaries during the study period. Blood samples were taken, body mass measured, and moult was scored twelve times for the same individuals from April to October. Blood parasites were detectable in smears during the whole study period with an intensity peak coinciding with breeding in the wild. Young birds had more parasites and a consistently higher body mass than older birds. There was no relationship between parasite intensity and mass in older birds but possibly one in young birds. Parasites did not seem to affect moult in either age class. Repeatability of parasite counts of smears from the same individual was very high and smears are therefore a reliable method for estimating parasite intensity. We conclude that blood parasites are probably most severe during, but occur in their hosts long after, the breeding season. Possible costs of parasites outside the breeding season require further study.

  • 18.
    Alm Bergvall, Ulrika
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. Swedish University of Agricultural Sciences, Sweden.
    Svensson, Lisa
    Kjellander, Petter
    Vigilance adjustments in relation to long- and short term risk in wild fallow deer (Dama dama)2016In: Behavioural Processes, ISSN 0376-6357, Vol. 128, 58-63 p.Article in journal (Refereed)
    Abstract [en]

    The risk allocation hypothesis predicts that vigilance should be adjusted to the temporal variation in risk. We test this hypothesis in wild fallow deer exposed to short term (disturbance) and long term (presence of a fawn after parturition) changes in risk. We recorded the proportion, frequency and type of vigilance and size of used area before and after parturition, in GPS-collared wild female fallow deer. Vigilance was divided in two main groups: non-grazing vigilance and grazing vigilance. The latter group was divided into grazing vigilance while chewing and a grazing vigilance when chewing was interrupted. By recording external disturbance in form of passing cars, we were able to investigate if this altered the amount, and type of vigilance. We found that females increased the proportion and frequency of grazing vigilance stop chewing after parturition. The grazing vigilance chewing was unaffected, but non-grazing vigilance decreased. Disturbance increased the proportion grazing vigilance stop chewing to the same extent before and after parturition. We found a clear decrease in female home range size after parturition as a possible behavioural adjustment. The increase in grazing vigilance stop chewing after parturition is a rarely described but expected cost of reproduction.

  • 19.
    Almbro, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology.
    Weight Loading and Reproductive Status Affect the Flight Performance of Pieris napi Butterflies2012In: Journal of insect behavior, ISSN 0892-7553, E-ISSN 1572-8889, Vol. 25, no 5, 441-452 p.Article in journal (Refereed)
    Abstract [en]

    Weight-induced mobility reductions can have dramatic fitness consequences and winged animals are especially sensitive to the trade-off between mass and locomotion. Data on how natural weight fluctuations influence a flying insect's ability to take off are scarce. We therefore quantified take-off flight ability in Pieris napi butterflies in relation to reproductive status. Take-off flight ability (velocity and take-off angle) under suboptimal temperature conditions was recorded with a 3D-tracking camera system and was predicted to decrease with relatively larger weight loads. Our results show that relatively larger weight loads generally reduce flight speed in male butterflies and lower take-off angles in females. However, despite having a lower wing loading, mated male butterflies flew slower than unmated males. Our study suggests that retention of weight loads associated with reproduction impairs insect flight performance.

  • 20.
    Almbro, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Impaired escape flight ability in butterflies due to low flight muscle ratio prior to hibernation2008In: Journal of Experimental Biology, ISSN 0022-0949, Vol. 211, no 1, 24-28 p.Article in journal (Refereed)
  • 21.
    Amcoff, Mirjam
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Fishing for Females: Sensory Exploitation in the Swordtail Characin2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Mate choice plays an important role in sexual selection and speciation. The evolution of mate choice is intriguing in cases where choosy individuals gain little except for genetic material from the mate and where the trait used as a criterion for the choice is costly to its bearer. The sensory exploitation hypothesis is an interesting idea that applies to such cases because it suggests that sexual preferences may arise as side-effects of preferences that are under selection in other contexts. The role of mate choice in speciation is strong but is debated because the reasons for population divergence in mate preferences and sexual traits are sometimes hard to explain. Also in this context sensory exploitation offers a potential explanation in that a link between natural and sexual selection may result in divergence in sexual selection whenever populations differ in natural selection.

    In this thesis, I test several aspects of this hypothesis in a species of fish, the swordtail characin (Corynopoma riisei). In this species males display a flag-like ornament that grows from the operculum. Because females respond to this ornament by biting at it, it has been proposed to act as a food-mimic. By manipulating female food type and quantity, and testing the resulting female preference for the male ornament, I find support for the theory that the preference has evolved through sensory exploitation and that females indeed appear to relate the ornament to a food item. Furthermore, I show that sensory exploitation can lead to morphological divergence among natural populations in this species. Apart from the flag-ornament, other courtship signals are also investigated. The results show that the relative importance of different signals may vary depending on receiver motivation. This suggests that various aspects of both male courtship signals and the conditions during which they are being signalled should be considered to gain a full understanding of mate choice and its role in sexual selection and speciation.

  • 22.
    Amininasab, Seyed Mehdi
    et al.
    Univ Groningen, Behav & Physiol Ecol, Groningen Inst Evolutionary Life Sci, POB 11103, NL-9700 CC Groningen, Netherlands.;Behbahan Khatam Alanbia Univ Technol, Dept Environm Sci, Behbahan, Iran..
    Xu, Charles C. Y.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology. Univ Groningen, Behav & Physiol Ecol, Groningen Inst Evolutionary Life Sci, POB 11103, NL-9700 CC Groningen, Netherlands..
    Kingma, Sjouke A.
    Univ Groningen, Behav & Physiol Ecol, Groningen Inst Evolutionary Life Sci, POB 11103, NL-9700 CC Groningen, Netherlands..
    Komdeur, Jan
    Univ Groningen, Behav & Physiol Ecol, Groningen Inst Evolutionary Life Sci, POB 11103, NL-9700 CC Groningen, Netherlands..
    Effect of tree logging on reproductive performance in Blue Tits (Cyanistes caeruleus)2017In: Journal of Ornithology = Journal fur Ornithologie, ISSN 0021-8375, E-ISSN 1439-0361, Vol. 158, no 1, 339-344 p.Article in journal (Refereed)
    Abstract [en]

    For birds, habitat quality is largely determined by local vegetation, and reproductive performance can therefore be negatively influenced by anthropogenic activities. A tree logging event enabled us to examine the effect of removing trees of different maturities and types on the reproductive performance of Blue Tits (Cyanistes caeruleus). Against expectations, only the logging of small coniferous trees, but not larger and deciduous trees, was associated with a reduction in the number of eggs laid, whereas logging had no significant effect on lay date. Therefore, we conclude that modest logging activity has no or limited negative influence on Blue Tit reproductive performance.

  • 23. Amundin, Mats
    et al.
    Eklund, Robert
    Hållsten, Henrik
    Karlgren, Jussi
    KTH, School of Computer Science and Communication (CSC), Theoretical Computer Science, TCS.
    Molinder, Lars
    A proposal to use distributional models to analyse dolphin vocalization2017In: 1st International Workshop on Vocal Interactivity in-and-between Humans, Animals and Robots, 2017, 2017Conference paper (Refereed)
    Abstract [en]

    This paper gives a brief introduction to the starting points of an experimental project to study dolphin communicative behaviour using distributional semantics, with methods implemented for the large scale study of human language.

  • 24.
    Ananthakrishnan, Gopal
    et al.
    Centre for Speech Technology, KTH, Stockholm, Sweden.
    Eklund, Robert
    Linköping University, Department of Computer and Information Science, NLPLAB - Natural Language Processing Laboratory. Linköping University, The Institute of Technology.
    Peters, Gustav
    Forschungsinstitut Alexander Koenig, Bonn, Germany.
    Mabiza, Evans
    Antelope Park, Gweru, Zimbabwe.
    An acoustic analysis of lion roars. II: Vocal tract characteristics2011In: Proceedings from Fonetik 2011, Quarterly Progress and Status Report TMH-QPSR, Volume 51, 2011, 2011, 5-8 p.Conference paper (Other academic)
    Abstract [en]

    This paper makes the first attempt to perform an acoustic-to-articulatory inversion of a lion (Panthera leo) roar. The main problems that one encounters in attempting this, is the fact that little is known about the dimensions of the vocal tract, other than a general range of vocal tract lengths. Precious little is also known about the articulation strategies that are adopted by the lion while roaring. The approach used here is to iterate between possible values of vocal tract lengths and vocal tract configurations. Since there seems to be a distinct articulatory changes during the process of a roar, we find a smooth path that minimizes the error function between a recorded roar and the simulated roar using a variable length articulatory model.

  • 25.
    Andersen, Emelie
    et al.
    Halmstad University, School of Business, Engineering and Science.
    Nilsson, Bertil
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), MPE-lab.
    Sahlén, Göran
    Halmstad University, School of Business, Engineering and Science, Biological and Environmental Systems (BLESS).
    Survival possibilities of the dragonfly Aeshna viridis (Insecta, Odonata) in southern Sweden predicted from dispersal possibilities2016In: Journal of Insect Conservation, ISSN 1366-638X, E-ISSN 1572-9753, Vol. 20, no 2, 179-188 p.Article in journal (Refereed)
    Abstract [en]

    We use public records from 1980 to 2014 to analyse survival of the EU Annex IV species Aeshna viridis in Sweden, a dragonfly strongly associated with the plant Stratiotes aloides. We clustered localities with S. aloides based on assumed dispersal abilities of A. viridis, using a dispersing radius of 2–100 km, calculating the proportion of sites with S. aloides that A. viridis is able to reach. If mean dispersal capability is high (40 km or above) 92.6 % or more of the localities are connected. For a good disperser, the probability of long-time survival is good. We further analysed the species richness of other Odonata and aquatic plants at 98 localities from the dataset. A. viridis co-occurred with more Odonata in the presence of S. aloides and running water but not in lakes. S. aloides sites had a higher number of other aquatic plants. Area had no impact on the occurrence of the species. For the present situation we surveyed 32 localities with known occurrence of the species. Only half of the sites for S. aloides contained any specimens while A. viridis occurred in the same number of sites. The species co-occurred in only 8 of 32 sites. In four sites A. viridis larvae appeared among Menyanthes trifoliata, Phragmites australis, Potamogeton natans and Sphagnum spp., indicating that at high latitudes A. viridis breeds among other species. Indirect monitoring based only on S. aloides would underestimate the number of populations of the dragonfly. © 2016 Springer International Publishing Switzerland

  • 26.
    Andersson, Anastasia
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Laikre, Linda
    Stockholm University, Faculty of Science, Department of Zoology.
    Bergvall, Ulrika A.
    Stockholm University, Faculty of Science, Department of Zoology. Swedish University of Agricultural Sciences, Sweden.
    Two shades of boldness: novel object and anti-predator behavior reflect different personality dimensions in domestic rabbits2014In: Journal of ethology, ISSN 0289-0771, E-ISSN 1439-5444, Vol. 32, no 3, 123-136 p.Article in journal (Refereed)
    Abstract [en]

    It is increasingly common to quantify and describe behavioral variation in domestic and wild animals in terms of personality. Correlating behavioral traits are referred to as personality dimensions or factors and different dimensions have been reported in different species. Boldness is a well-described personality dimension in several species, although some issues remain unclear. Previous models of boldness include both novelty and risk taking, but recent studies indicate that these types of behaviors may reflect separate personality dimensions. In this study, we developed a behavioral test battery for domestic rabbits, and recorded behaviors of 61 individuals in four different situations (novel object, novel arena, social, and predator interactions). We used domestic rabbits as a model because behavioral variation in rabbits has rarely been quantified in terms of personality dimensions, although rabbit behavior is described. We also wanted to investigate behavioral variation in a Swedish rabbit breed of conservation concern - the Gotland rabbit. Factor analysis of the behavioral test measures suggested three personality dimensions: exploration, boldness, and anxiety. Novel object scores clustered in the exploration and boldness factors, whereas scores associated with predator interactions were explained by anxiety, indicating that novel object and anti-predator behavior reflect different personality dimensions in rabbits.

  • 27.
    Andersson, Gunnar
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Evolutionary Biology, Comparative Physiology.
    Differentiation and Pathogenicity within the Saprolegniaceae: Studies on Physiology and Gene Expression Patterns in Saprolegnia parasitica and Aphanomyces astaci2001Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Saprolegnia parasitica and Aphanomyces astaci are parasitic water moulds belonging to the Oomycetes. Despite their importance as parasites they are very little studied at the molecular level and the work described in this thesis was aimed at increasing the molecular knowledge of these organisms by cloning and characterising genes of potential importance for reproduction and pathogenicity.

    Stage-specific transcripts from Saprolegnia parasitica were isolated by differential display RT-PCR. One of the markers, puf1 encodes a putative mRNA binding protein which may be involved in post-transcriptional regulation of gene expression. S. parasitica puf1 is expressed exclusively in spore cysts that have not been determined for germination or repeated zoospore emergence indicating that the cyst stage has two phases, of about equal duration, which are physiologically and transcriptionally distinct. A similar expression pattern is observed in Aphanomyces spp. with different regulation of spore development and in the transcript is detected in both primary and secondary cysts.

    A putative chitinase AaChi1, was cloned from the crayfish plague fungus, Aphanomyces astaci. Analysis of chitinase activity and AaChi1 expression showed that chitinase in A. astaci is constitutively expressed in growing and sporulating mycelia, but absent in zoospores, a pattern which reflects the infectious life cycle of A. astaci. This expression pattern is conserved between the four known genotypes of A. astaci, in contrast to saprophytic and fish-pathogenic Aphanomyces spp.

    Genetic and physiological analysis were conducted on five strains of Aphanomyces, isolated from suspected outbreaks of crayfish plague in Spain and Italy. The strains are not virulent against freshwater crayfish, and RAPD PCR and ITS sequence analysis show that they are unrelated to the crayfish plague fungus, A. astaci.

  • 28. Andersson, J.
    et al.
    Dahl, J.
    Johansson, A.
    Karås, P.
    Nilsson, J.
    Sandström, O.
    Svensson, P. Andreas
    Utslagen fiskrekrytering och sviktande fiskbestånd i Kalmar läns kustvatten. (English title: Recruitment failure and decreasing fish stocks in the coastal areas of Kalmarsund.)2000Report (Refereed)
  • 29.
    Andersson, Julia
    Halmstad University, School of Business, Engineering and Science.
    Does clearcutting as a method for forestry impact the aquatic life in lakes nearby?2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Clearcutting is the most common method for forestry in Sweden. However research shows that this type of intense management can have a negative impact on biological biodiversity as it interferes with an area’s natural characteristics. Previous studies have mainly focused on biological effects on land. In this study dragonflies were used as biological indicators to investigate the impact of clearcutting in aquatic environments. The result from this study indicate that the use of clearcutting as a method for forestry can, with a certain postponement in time, negatively affect the species diversity of Odonata, and thus also the aquatic biodiversity in lakes in the immediate surroundings of a clearcut area, although it is still unclear exactly how and by which mechanisms. It is also uncertain if the effects are only temporarily, or long-term. If Sweden is to reach the environmental goal of Flourishing Lakes and Streams, it is essential to adopt further safety measures when conducting clearcutting near waters to avoid negative impact on the aquatic biological diversity.

  • 30. Andersson, Ki
    et al.
    Norman, David
    Werdelin, Lars
    Swedish Museum of Natural History, Department of Paleobiology.
    Sabertoothed carnivores and the killing of large prey2011In: PLoS ONE, ISSN 1932-6203, Vol. 6, no 10, e24971- p.Article in journal (Refereed)
    Abstract [en]

    Sabre-like canines clearly have the potential to inflict grievous wounds leading to massive blood loss and rapid death. Hypotheses concerning sabretooth killing modes include attack to soft parts such as the belly or throat, where biting deep is essential to generate strikes reaching major blood vessels. Sabretoothed carnivorans are widely interpreted as hunters of larger and more powerful prey than that of their present-day nonsabretoothed relatives. However, the precise functional advantage of the sabretooth bite, particularly in relation to prey size, is unknown. Here, we present a new point-to-point bite model and show that, for sabretooths, depth of the killing bite decreases dramatically with increasing prey size. The extended gape of sabretooths only results in considerable increase in bite depth when biting into prey with a radius of less than ~10 cm. For sabretooths, this size-reversed functional advantage suggests predation on species within a similar size range to those attacked by present-day carnivorans, rather than “megaherbivores” as previously believed. The development of the sabretooth condition appears to represent a shift in function and killing behaviour, rather than one in predator-prey relations. Furthermore, our results demonstrate how sabretoothed carnivorans are likely to have evolved along a functionally continuous trajectory: beginning as an extension of a jaw-powered killing bite, as adopted by present-day pantherine cats, followed by neck-powered biting and thereafter shifting to neck-powered shear-biting. We anticipate this new insight to be a starting point for detailed study of the evolution of pathways that encompass extreme specialisation, for example, understanding how neck-powered biting shifts into shear-biting and its significance for predator-prey interactions. We also expect that our model for point-to-point biting and bite depth estimations will yield new insights into the behaviours of a broad range of extinct predators including therocephalians (gorgonopsian + cynodont, sabretoothed mammal-like reptiles), sauropterygians (marine reptiles) and theropod dinosaurs.

  • 31. Andersson, Ki
    et al.
    Werdelin, Lars
    Swedish Museum of Natural History, Department of Paleobiology.
    Carnivora from the Late Miocene of Lantian, China2005In: Vertebrata PalAsiatica, Vol. 43, 256-271 p.Article in journal (Refereed)
    Abstract [en]

    Sediments of the Bahe and Lantian formations, Lantian area, Shaanxi Province, China, have produced a large number of mammalian fossils. This Late Miocene sequence provides evidence for a period of major changes in the physical environment of the region. The carnivoran fossils are described and analyzed herein. The following species are present: lctitherium viverrinum, Hyaenictitherium cf . H. wongii and Adcrocuta eximia ( Hyaenidae) , cf. Metailurus major and cf. Metailurus parvulus ( Felidae) . Although a difference in the composition of the carnivoran fauna is noted towards the boundary between the Bahe Formation (lower) and Lantian Formation (upper), the cause of this is yet to be determined.

  • 32.
    Andersson, Måns Sverker
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Animal Ecology. zooekologi.
    Gustafsson, Lars
    Glycosylated haemoglobin: a new measure of condition in birds1995In: Proceedings of the Royal Society of London, no 260, 299-303 p.Article in journal (Refereed)
    Abstract [en]

    Abstract: The influence of condition on time of breeding and reproductive success has been discussed since Darwin first suggested a relation in 1871. We used a novel method to investigate the influence of condition on the timing of breeding and reproductive success by measuring a relatively inert physiological parameter - the amount of glycosylated haemoglobin - in blood samples taken from the collared flycatcher Ficedula albicollis. The percentage of glycosylated haemoglobin (%HbG) was assumed to be proportional to the average blood glucose level, during the 3-5 weeks before the blood sampling. The %HbG was influenced neither by sex nor age. Date of arrival at the breeding ground was negatively correlated with %HbG so that early-arriving birds had significantly higher %HbG than those arriving later. Clutch size, corrected for the effect of laying date, correlated positively with %HbG in females, as did the number of fledged young, corrected for the effect of laying date, for both sexes. We found no correlation between body mass and the %HbG. We suggest that prebreeding condition influences the timing of breeding and subsequent reproductive performance and that %HbG can be used as an indicator of prebreeding-condition in migrating birds.

  • 33.
    Andersson, Ulf
    Stockholm University, Faculty of Science, The Wenner-Gren Institute , Physiology.
    On the biosynthesis of ATP synthase1998Doctoral thesis, comprehensive summary (Other academic)
  • 34. Angerbjorn, Anders
    et al.
    Eide, Nina E.
    Dalen, Love
    Elmhagen, Bodil
    Hellstrom, Peter
    Ims, Rolf A.
    Killengreen, Siw
    Landa, Arild
    Meijer, Tomas
    Mela, Matti
    Niemimaa, Jukka
    Noren, Karin
    Tannerfeldt, Magnus
    Yoccoz, Nigel G.
    Henttonen, Heikki
    Carnivore conservation in practice: replicated management actions on a large spatial scale2013In: Journal of Applied Ecology, ISSN 0021-8901, E-ISSN 1365-2664, Vol. 50, no 1, 59-67 p.Article in journal (Refereed)
  • 35.
    Angerbjörn, Anders
    Stockholm University, Faculty of Science, Department of Zoology.
    Reproduction of Mountain Hares (Lepus-Timidus) in Relation to Density and Physical Condition1986In: Journal of Zoology, Vol. 208, no 4, 559-568 p.Article in journal (Refereed)
    Abstract [en]

    Population estimates of Mountain hares were done on three islands off the west coast of Sweden. Three different relative measures of hare reproduction were negatively related to density. Most of this relationship was accounted for through a positive correlation with body condition. However, there was no significant density trend in litter size or number of litters. The start of the reproductive season each year was related to mean air temperature during spring, so when spring was early so was conception.

  • 36.
    Angerbjörn, Anders
    Stockholm University, Faculty of Science, Department of Zoology.
    Gigantism in Island Populations of Wood Mice (Apodemus) in Europe1986In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 47, no 1, 47-56 p.Article in journal (Refereed)
    Abstract [en]

    Many rodents have large body sizes on islands, and there are many hypotheses that try to explain this observed pattern. Using body size data on Apodemus in Europe as an example, I try to evaluate the main hypotheses. These can be divided in four different categories. 1) Hypotheses assuming climatic differences between islands and mainland: no trend in body size on islands in the Mediterranean, in Britain or in the Baltic area is observed. 2) Hypotheses based on island size: no trend is observed in the data analysed. 3) Hypotheses based on distance to mainland: no general effect is found, although there is an effect in the British material. 4) Hypotheses based on faunistic differences: consistent relationships are found in all areas. A. sylvaticus shows larger body size when lacking competition from A. flavicollis or Clethrionomys glareolus or when predation is absent. A. flavicollis is larger when predators are lacking, and smaller when no competitors are present. This is in agreement with character displacement theory

  • 37.
    Angerbjörn, Anders
    Stockholm University, Faculty of Science, Department of Zoology.
    The Evolution of Body Size in Mammals on Islands - Some Comments1985In: American Naturalist, ISSN 0003-0147, E-ISSN 1537-5323, Vol. 125, no 2, 304-309 p.Article in journal (Refereed)
  • 38.
    Angerbjörn, Anders
    Stockholm University, Faculty of Science, Department of Zoology.
    The Effect of Red Fox Predation on Mountain Hare Populations on Islands1986In: Mammal Review, ISSN 0305-1838, E-ISSN 1365-2907, Vol. 16, no 3-4, 198-198 p.Article in journal (Refereed)
    Abstract [en]

    The population dynamics of Mountain Hares on islands have been monitored during 10 years. In some years Red Foxes have been present on some islands. The intensity of predation on the hares is given from the reduction of the known hare densities, and from the foxes’ diet (scat analysis). The effect of predation on the hare populations was found to be density dependent, but also dependent on the alternative food available.

    [Complete text from journal]

  • 39.
    Angerbjörn, Anders
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Arvidson, Bengt
    Stockholm University, Faculty of Science, Department of Zoology.
    Norén, Erik
    Strömgren, Lasse
    The Effect of Winter Food on Reproduction in the Arctic Fox, Alopex-Lagopus - a Field Experiment1991In: Journal of Animal Ecology, Vol. 60, no 2, 705-714 p.Article in journal (Refereed)
    Abstract [en]

    (1) The population of arctic foxes in Fennoscandia is very small and has been so for around 60 years in spite of total protection for over half a century. The reasons why the arctic fox population has not increased to its former size are unknown. The population numbers fluctuate highly in relation to vole numbers. There is also very high interannual variation in reproduction among arctic foxes. (2) To determine the effect of winter food availability on reproductive success, we carried out a feeding experiment. The study area is situated above the treeline from an altitude of 700 m to mountains of 1600 m in Swedish Lapland. We added food (reindeer and moose carcasses) to dens during the winter months, January-April 1985-89. To determine the effect of this extra food on reproduction, we made inventories at both food-manipulated dens and control dens. These inventories of dens took place during July so we could check not only if dens were occupied, but also whether a litter was born and assess the number of cubs appearing outside the den. (3) The proportion of occupied dens in the experimental group was significantly higher than in the control group. The number of cubs at weaning in the food-manipulated dens was also higher than in control dens in each year. However, no effect on litter size was found. (4) From these results we conclude that the larger number of cubs produced in dens with extra winter food shows that reproduction under present dietary poor conditions was limited by available food. Many canid species show this close relation between reproduction and food availability, with pregnancy rates and litter sizes declining with the abundance of the main food.

  • 40.
    Angerbjörn, Anders
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Börjesson, Patrik
    Stockholm University, Faculty of Science, Department of Zoology.
    Brandberg, K.
    Stable isotope analysis of harbour porpoises and their prey from the Baltic and Kattegat/Skagerrak Seas2006In: Marine Biology Research, ISSN 1745-1000, Vol. 2, no 6, 411-419 p.Article in journal (Refereed)
    Abstract [en]

    The by-caught harbour porpoises in commercial fisheries have raised concerns over their conservation status in the Baltic region. One important aspect for management purposes is porpoise movements within the region. We measured stable isotopes in cod, herring and hagfish, species that are important prey for harbour porpoises in the Baltic region. Bone collagen in fish from the marine Kattegat/Skagerrak was significantly enriched in C-13 compared with collagen in fish from the brackish Baltic Sea. However, despite the isotopic variation seen in their prey, we found no difference in C-13 in harbour porpoise collagen from the two areas. In fact, only eight of 24 porpoises had isotope signatures corresponding to those estimated for the diet in the area where they were caught. Our general conclusion is that porpoises move between the Baltic and Kattegat/Skagerrak Seas. Future studies are needed to evaluate the magnitude of these movements.

  • 41.
    Angerbjörn, Anders
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Hjernquist, B.
    A Rapid Summer Decline in a Mountain Hare Population on an Island1984In: Acta Theriologica, ISSN 0001-7051, Vol. 29, no 1-10, 63-75 p.Article in journal (Refereed)
  • 42.
    Angerbjörn, Anders
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Pehrson, A.
    Factors Influencing Winter Food Choice by Mountain Hares (Lepus-Timidus L) on Swedish Coastal Islands1987In: Canadian Journal of Zoology, ISSN 0008-4301, E-ISSN 1480-3283, Vol. 65, no 9, 2163-2167 p.Article in journal (Refereed)
    Abstract [en]

    In mainland areas, mountain hares seem unable to survive on a single browse species. However, mountain hares on islands off the west coast of Sweden rely almost entirely on a plain heather diet during winter. Herein, we give as a possible explanation for this phenomenon that the high concentration of sodium in the heather in the coastal areas can buffer the high sodium excretion otherwise observed in hares feeding on heather under experimental conditions. Furthermore, hares selected heather with the highest nitrogen and phosphorus contents. We argue that the pattern of food choice exhibited by the hares in the coastal area is to be expected in homogenous habitats where hares rely on one dominant food species. In heterogenous habitats, the possibility of food selection on a nutritional level is to a considerable extent overridden by effects of digestibility and concentration of secondary compounds in the different food plants available.

  • 43.
    Angerbjörn, Anders
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Tannerfeldt, M.
    Stockholm University, Faculty of Science, Department of Zoology.
    Bjärvall, A.
    Ericson, M.
    From, J.
    Noren, E.
    Dynamics of the Arctic Fox Population in Sweden1995In: Annales Zoologici Fennici, Vol. 32, no 1, 55-68 p.Article in journal (Refereed)
    Abstract [en]

    Arctic fox populations fluctuate widely with the abundance of prey, i.e. lemmings and voles (Arvicolinae). We have investigated the patterns and mechanisms of these fluctuations in arctic fox numbers through den inventories during 20 years (1974-1993) in Sweden. Time series analyses confirmed a four-year cyclicity in both arctic fox numbers and litter size. However, the different geographical regions were not in synchrony. The fox population in the southern parts of the distribution range has shown regular peaks during the whole period, whereas those in the northern and middle parts of Sweden have declined since 1982. In the northernmost county, also litter sizes have decreased. These differences coincided with an absence of vole and lemming peaks in the north. Experimental feeding confirmed that food availability had a direct impact on breeding success and litter size, thereby limiting the population. We conclude that the total number of arctic foxes in Sweden in 1994 is as low as 40-80 animals.

  • 44.
    Angerbjörn, Anders
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Tannerfeldt, Magnus
    Stockholm University, Faculty of Science, Department of Zoology.
    Erlinge, S.
    Predator-prey relationships: Arctic foxes and lemmings1999In: Journal of Animal Ecology, Vol. 68, no 1, 34-49 p.Article in journal (Refereed)
    Abstract [en]

    1. The number of breeding dens and litter sizes of arctic foxes Alopex lagopus were recorded and the diet of the foxes was analysed during a ship-based expedition to 17 sites along the Siberian north coast. At the same time the cyclic dynamics of coexisting lemming species were examined. 2. The diet of arctic foxes was dominated by the Siberian lemming Lemmus sibiricus (on one site the Norwegian lemming L. lemmus), followed by the collared lemming Dicrostonyx torquatus. 3. The examined Lemmus sibiricus populations were in different phases of the lemming cycle as determined by age profiles and population densities. 4. The numerical response of arctic foxes to varying densities of Lemmus had a time lag of 1 year, producing a pattern of limit cycles in lemming-arctic fox interactions, Arctic fox litter sizes showed no time lag, but a linear relation to Lemmus densities. We found no evidence for a numerical response to population density changes in. Dicrostonyx. 5. The functional or dietary response of arctic foxes followed a type II curve for Lemmus, but a type III response curve for Dicrostonyx. 6. Arctic foxes act as resident specialist for Lemmus and may increase the amplitude and period of their population cycles. For Dicrostonyx, on the other hand, arctic foxes act as generalists which suggests a capacity to dampen oscillations.

  • 45.
    Angerbjörn, Anders
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Tannerfeldt, Magnus
    Stockholm University, Faculty of Science, Department of Zoology.
    Lundberg, Håkan
    Stockholm University, Faculty of Science, Department of Zoology.
    Geographical and temporal patterns of lemming population dynamics in Fennoscandia2001In: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 24, no 3, 298-308 p.Article in journal (Refereed)
    Abstract [en]

    There is a long-lasting debate in ecology on cyclicity, synchrony and time lags of lemming population fluctuations. We have analysed 137 yr of previously published population data on the Norwegian lemming Lemmus lemmus in ten geographic regions of Fennoscandia. The dominating pattern was synchronous 4-yr cycles. There was no support for the hypothesis of a north-south gradient in cycle length. However. we found periods of prolonged interruptions in the cyclicity, which were more common in northern areas. Wa found a high degree of synchrony between regions. with only a weak relationship to distance, The observed pattern in lemming population dynamics was more consistent with effects from extrinsic factors, such as climate. than intrinsic factors. such as dispersal.

  • 46. Antonopoulou, Efthimia
    et al.
    Swanson, Penny
    Borg, Bertil
    Stockholm University, Faculty of Science, Department of Zoology.
    Effects of aromatase inhibitors and different doses of testosterone on gonadotropins in one year old male Atlantic salmon (Salmo salar).2009In: Comparative biochemistry and physiology. Part A, Molecular & integrative physiology, ISSN 1531-4332, Vol. 153, no 4, 408-16 p.Article in journal (Refereed)
    Abstract [en]

    The effects of different doses of testosterone (T), the aromatase inhibitors 1,4,6-androstatriene-3,17-dione (ATD) and 4-hydroxy-4-androstene-3,17-dione (4OH), and the combined treatment of T and ATD on luteinizing hormone (LH) and follicle-stimulating hormone (FSH) at the onset of puberty in juvenile Atlantic salmon males were investigated. T always increased pituitary LH. Also, ATD increased pituitary LH, though to a lesser extent than T. However, ATD combined with T diminished pituitary LH levels compared to T alone, indicating an aromatase-dependent positive feedback of T on LH in immature males. 4OH, which was less effective than ATD as an aromatase inhibitor, increased LH content. ATD treatment resulted in increased pituitary FSH levels, similar to those of mature controls. Positive effects of ATD on plasma FSH were found, indicating the presence of an aromatase-dependent negative feedback. The 4OH effects on FSH levels were inconsistent. T exerted both positive and negative effects on pituitary FSH and testes growth, depending on dose and season, with the positive effects being more pronounced with the low doses and the negative effects with the high doses. The treatment of T combined with ATD did not affect the positive effect of T alone on pituitary and plasma FSH, indicating the presence of an aromatase-independent positive feedback on FSH. There was a positive correlation between FSH and gonadosomatic index, especially during summer when gonadal development occurs.

  • 47.
    Aplin, L. M.
    et al.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England.;Univ Calif Davis, Dept Anthropol, Davis, CA 95616 USA..
    Firth, J. A.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Farine, D. R.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England.;Univ Calif Davis, Dept Anthropol, Davis, CA 95616 USA.;Smithsonian Trop Res Inst, Ancon, Italy..
    Voelkl, B.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Crates, R. A.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Culina, A.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Garroway, C. J.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Hinde, C. A.
    Wageningen Univ, Dept Anim Sci, Behav Ecol Grp, NL-6700 AP Wageningen, Netherlands..
    Kidd, L. R.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Psorakis, I.
    Univ Oxford, Math Inst, Oxford, England..
    Milligan, N. D.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Radersma, R.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England.;Lund Univ, Dept Biol, Evolutionary Ecol Unit, Lund, Sweden..
    Verhelst, B. L.
    Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Sheldon, B. C.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics. Univ Oxford, Dept Zool, Edward Grey Inst Field Ornithol, Oxford OX1 3PS, England..
    Consistent individual differences in the social phenotypes of wild great tits, Parus major2015In: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 108, 117-127 p.Article in journal (Refereed)
    Abstract [en]

    Despite growing interest in animal social networks, surprisingly little is known about whether individuals are consistent in their social network characteristics. Networks are rarely repeatedly sampled; yet an assumption of individual consistency in social behaviour is often made when drawing conclusions about the consequences of social processes and structure. A characterization of such social phenotypes is therefore vital to understanding the significance of social network structure for individual fitness outcomes, and for understanding the evolution and ecology of individual variation in social behaviour more broadly. Here, we measured foraging associations over three winters in a large PIT-tagged population of great tits, and used a range of social network metrics to quantify individual variation in social behaviour. We then examined repeatability in social behaviour over both short (week to week) and long (year to year) timescales, and investigated variation in repeatability across age and sex classes. Social behaviours were significantly repeatable across all timescales, with the highest repeatability observed in group size choice and unweighted degree, a measure of gregariousness. By conducting randomizations to control for the spatial and temporal distribution of individuals, we further show that differences in social phenotypes were not solely explained by within-population variation in local densities, but also reflected fine-scale variation in social decision making. Our results provide rare evidence of stable social phenotypes in a wild population of animals. Such stable social phenotypes can be targets of selection and may have important fitness consequences, both for individuals and for their social-foraging associates.

  • 48. Arganda, S.
    et al.
    Nicolis, Stamatios C.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Mathematics.
    Perochain, A.
    Pechabadens, C.
    Latil, G.
    Dussutour, A.
    Collective choice in ants: The role of protein and carbohydrates ratios2014In: Journal of insect physiology, ISSN 0022-1910, E-ISSN 1879-1611, Vol. 69, 19-26 p.Article in journal (Refereed)
    Abstract [en]

    In a foraging context, social insects make collective decisions from individuals responding to local information. When faced with foods varying in quality, ants are known to be able to select the best food source using pheromone trails. Until now, studies investigating collective decisions have focused on single nutrients, mostly carbohydrates. In the environment, the foods available are a complex mixture and are composed of various nutrients, available in different forms. In this paper, we explore the effect of protein to carbohydrate ratio on ants' ability to detect and choose between foods with different protein characteristics (free amino acids or whole proteins). In a two-choice set up, Argentine ants Linepithema humile were presented with two artificial foods containing either whole protein or amino acids in two different dietary conditions: high protein food or high carbohydrate food. At the collective level, when ants were faced with high carbohydrate foods, they did not show a preference between free amino acids or whole proteins, while a preference for free amino acids emerged when choosing between high protein foods. At the individual level, the probability of feeding was higher for high carbohydrates food and for foods containing free amino acids. Two mathematical models were developed to evaluate the importance of feeding probability in collective food selection. A first model in which a forager deposits pheromone only after feeding, and a second model in which a forager always deposits pheromone, but with greater intensity after feeding. Both models were able to predict free amino acid selection, however the second one was better able to reproduce the experimental results suggesting that modulating trail strength according to feeding probability is likely the mechanism explaining amino acid preference at a collective level in Argentine ants.

  • 49.
    Arnqvist, Göran
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Sexual selection and intersexual conflicts in water striders1992Doctoral thesis, comprehensive summary (Other academic)
  • 50.
    Arnqvist, Göran
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal ecology.
    Rowe, Locke
    The shape of preference functions and what shapes them: a comment on Edward2015In: Behavioral Ecology, ISSN 1045-2249, E-ISSN 1465-7279, Vol. 26, no 2, 325-325 p.Article in journal (Other academic)
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