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  • 301.
    Kolodziejczyk, Agata
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Rieger, Dirk
    Helfrich-Förster, Charlotte
    Nässel, Dick
    Stockholm University, Faculty of Science, Department of Zoology.
    The GABAB receptor is expressed by PDF-producing clockneurons and modulates circadian locomotor activity in DrosophilaManuscript (preprint) (Other academic)
  • 302.
    Kolodziejczyk, Agata
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Sun, Xuejun
    Meinertzhagen, Ian A.
    Nässel, Dick R.
    Stockholm University, Faculty of Science, Department of Zoology.
    Glutamate, GABA and acetylcholine signaling components in the lamina of the Drosophila visual system2008In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 3, no 5, p. e2110-Article in journal (Refereed)
    Abstract [en]

    Synaptic connections of neurons in the Drosophila lamina, the most peripheral synaptic region of the visual system, have been comprehensively described. Although the lamina has been used extensively as a model for the development and plasticity of synaptic connections, the neurotransmitters in these circuits are still poorly known. Thus, to unravel possible neurotransmitter circuits in the lamina of Drosophila we combined Gal4 driven green fluorescent protein in specific lamina neurons with antisera to γ-aminobutyric acid (GABA), glutamic acid decarboxylase, a GABAB type of receptor, L-glutamate, a vesicular glutamate transporter (vGluT), ionotropic and metabotropic glutamate receptors, choline acetyltransferase and a vesicular acetylcholine transporter. We suggest that acetylcholine may be used as a neurotransmitter in both L4 monopolar neurons and a previously unreported type of wide-field tangential neuron (Cha-Tan). GABA is the likely transmitter of centrifugal neurons C2 and C3 and GABAB receptor immunoreactivity is seen on these neurons as well as the Cha-Tan neurons. Based on an rdl-Gal4 line, the ionotropic GABAA receptor subunit RDL may be expressed by L4 neurons and a type of tangential neuron (rdl-Tan). Strong vGluT immunoreactivity was detected in α-processes of amacrine neurons and possibly in the large monopolar neurons L1 and L2. These neurons also express glutamate-like immunoreactivity. However, antisera to ionotropic and metabotropic glutamate receptors did not produce distinct immunosignals in the lamina. In summary, this paper describes novel features of two distinct types of tangential neurons in the Drosophila lamina and assigns putative neurotransmitters and some receptors to a few identified neuron types.

  • 303.
    Kotrschal, Alexander
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology. Uppsala University, Sweden.
    Corral-Lopez, Alberto
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Amcoff, Mirjam
    Kolm, Niclas
    Stockholm University, Faculty of Science, Department of Zoology, Ethology. Uppsala University, Sweden.
    A larger brain confers a benefit in a spatial mate search learning task in male guppies2015In: Behavioral Ecology, ISSN 1045-2249, E-ISSN 1465-7279, Vol. 26, no 2, p. 527-532Article in journal (Refereed)
    Abstract [en]

    Brain size varies dramatically among vertebrates, and selection for increased cognitive abilities is thought to be the key force underlying the evolution of a large brain. Indeed, numerous comparative studies suggest positive relationships between cognitively demanding aspects of behavior and brain size controlled for body size. However, experimental evidence for the link between relative brain size and cognitive ability is surprisingly scarce and to date stems from a single study on brain size selected guppies (Poecilia reticulata), where large-brained females were shown to outperform small-brained females in a numerical learning assay. Because the results were inconclusive for males in that study, we here use a more ecologically relevant test of male cognitive ability to investigate whether or not a relatively larger brain increases cognitive ability also in males. We compared mate search ability of these artificially selected large-and small-brained males in a maze and found that large-brained males were faster at learning to find a female in a maze. Large-brained males decreased the time spent navigating the maze faster than small-brained males and were nearly twice as fast through the maze after 2 weeks of training. Our results support that relatively larger brains are better also for males in some contexts, which further substantiates that variation in vertebrate brain size is generated through the balance between energetic costs and cognitive benefits.

  • 304.
    Kotrschal, Alexander
    et al.
    Department of Ecology & Genetics/Animal Ecology, Uppsala University, Sweden.
    Lievens, Eva J. P.
    Dahlbom, Josefin
    Bundsen, Andreas
    Semenova, Svetlana
    Sundvik, Maria
    Maklakov, Alexei A.
    Winberg, Svante
    Panula, Pertti
    Kolm, Niclas
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Artificial selection on relative brain size reveals a positive genetic correlation between brain size and proactive personality in the guppy2014In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 68, no 4, p. 1139-1149Article in journal (Refereed)
    Abstract [en]

    Animal personalities range from individuals that are shy, cautious, and easily stressed (a reactive personality type) to individuals that are bold, innovative, and quick to learn novel tasks, but also prone to routine formation (a proactive personality type). Although personality differences should have important consequences for fitness, their underlying mechanisms remain poorly understood. Here, we investigated how genetic variation in brain size affects personality. We put selection lines of large- and small-brained guppies (Poecilia reticulata), with known differences in cognitive ability, through three standard personality assays. First, we found that large-brained animals were faster to habituate to, and more exploratory in, open field tests. Large-brained females were also bolder. Second, large-brained animals excreted less cortisol in a stressful situation (confinement). Third, large-brained animals were slower to feed from a novel food source, which we interpret as being caused by reduced behavioral flexibility rather than lack of innovation in the large-brained lines. Overall, the results point toward a more proactive personality type in large-brained animals. Thus, this study provides the first experimental evidence linking brain size and personality, an interaction that may affect important fitness-related aspects of ecology such as dispersal and niche exploration.

  • 305.
    Kress, Timm
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Harzsch, Steffen
    University of Greifswald, Germany.
    Dircksen, Heinrich
    Stockholm University, Faculty of Science, Department of Zoology, Functional Morphology.
    Neuroanatomy of the optic ganglia and central brain of the water flea Daphnia magna (Crustacea, Cladocera)2016In: Cell and Tissue Research, ISSN 0302-766X, E-ISSN 1432-0878, Vol. 363, no 3, p. 649-677Article in journal (Refereed)
    Abstract [en]

    We reveal the neuroanatomy of the optic ganglia and central brain in the water flea Daphnia magna by use of classical neuroanatomical techniques such as semi-thin sectioning and neuronal backfilling, as well as immunohistochemical markers for synapsins, various neuropeptides and the neurotransmitter histamine. We provide structural details of distinct neuropiles, tracts and commissures, many of which were previously undescribed. We analyse morphological details of most neuron types, which allow for unravelling the connectivities between various substructural parts of the optic ganglia and the central brain and of ascending and descending connections with the ventral nerve cord. We identify 5 allatostatin-A-like, 13 FMRFamide-like and 5 tachykinin-like neuropeptidergic neuron types and 6 histamine-immunoreactive neuron types. In addition, novel aspects of several known pigment-dispersing hormone-immunoreactive neurons are re-examined. We analyse primary and putative secondary olfactory pathways and neuronal elements of the water flea central complex, which displays both insect- and decapod crustacean-like features, such as the protocerebral bridge, central body and lateral accessory lobes. Phylogenetic aspects based upon structural comparisons are discussed as well as functional implications envisaging more specific future analyses of ecotoxicological and endocrine disrupting environmental chemicals.

  • 306.
    Kuang, Wen
    Stockholm University.
    Genetic and Functional Analysis of Cell Adhesion in Muscle1998Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Skeletal muscle is one of the most abundant tissues in the body, and its main function is to generate the force for movement. The mature muscle cell is a giant, elongated, multinucleated cell surrounded by a specialized, extracellular matrix (ECM), the basement membrane (BM). The BM in muscle, as in other tissues, is composed of laminin, type IV collagen, entactin/nidogen and heparan sulphate proteoglycan. One major component of the BM in muscle is laminin-2, which is composed of a heavy chain laminina2 and two light chains,b1 and lamining1. Laminin-2 is predominantly expressed in skeletal muscle and peripheral nerve but is also found in other tissues.

    Cell adhesion to the basement membrane is mediated by cell surface receptors, which thereby link the BM to the cytoskeleton. This linkage is thought to be important for generating the force required for movement. Mutations in adhesion molecules in muscle cause muscular dystrophy, proving the importance of cell adhesion in muscle.

    In order to analyze the molecular mechanisms of cell adhesion in muscle, we have analyzed laminin-2 and two other muscle adhesion proteins, laminina-sarcoglycan and tetranectin, in muscle development and regeneration. Most importantly, we have developed in vitro and in vivo models for laminin-2 deficient muscular dystrophy.

    We generated several lines of mutant embryonic stem (ES) cell with disruption of the laminin- laminina2 chain gene. We found that homozygous null mutant ES cells differentiate normally in vitro, giving rise to cardiomyocytes, myotubes, and smooth muscle cells in addition to many other cell types. However, the myotubes that are formed are unstable. They detach, collapse, and degenerate, a process which is initiated at the appearance of the mature, contractile phenotype of the cells. We propose that the detachment and death of contracting myotubes in vitro has its counterpart in vivo, and that contraction-induced myofiber damage, along with the lack of survival cues provided by laminin-2/merosin, is a significant contribution to muscle degeneration in merosin-deficient muscular dystrophy.

    We used laminin laminina2 mutant mice to study the expression of laminin-2 in development and regeneration using the lacZ gene as a reporter for the lama2 gene. We found that the lacZ/lama2 gene is highly expressed in the early stages of myogenesis and is down regulated when myogenesis is completed. Most importantly, the gene is up-regulated early in muscle regeneration, suggesting that laminin-2 plays an important role in this process. Despite the prominent expression of lama2 in normal development, laminina2 null mutant mice have no obvious developmental defect. Instead, they develop muscular dystrophy two weeks after birth. We found extensive apoptosis in null mutant mice, and this cell death is dramatically reduced in mice in which laminin-2 expression is restored in skeletal muscle by expression of a wild type LAMA2 transgene. Most of the apoptotic cells in null mutant mice are newly formed myofibers, suggesting that laminin-2 is needed for maturation and survival of regenerated myotubes. The apparent abortive muscle regeneration in laminin-2 deficiency suggests that the severe disease of MCMD is caused by insufficient regeneration after muscle damage.

    We have expressed a human LAMA2 transgene under the regulation of a muscle-specific creatine kinase promoter in mice with complete or partial deficiency of merosin. The transgene restored the synthesis and localization of laminin-2 in skeletal muscle, and greatly improved muscle morphology and integrity and the health and longevity of the mice. However, the transgenic mice share with the non-transgenic dystrophic mice a progressive lameness of hind legs, suggesting a nerve defect. These results indicate that the absence of merosin in tissues other than the muscle, such as nervous tissue, is a critical component of MCMD.

    We have cloned and characterized, a-sarcoglycan/adhalin, a member of the dystrophin associated sarcoglycan complex in muscle. We showed that a-sarcoglycan is expressed very late in myogenic differentiation both in vitro and in vivo. In fact, the expression is associated with the capacity of muscle cells to contract. The sarcoglycans may therefore have a role in muscle contraction. We also analyzed an ECM-associated molecule, tetranectin. We showed that expression of tetranectin is closely associated with skeletal muscle development and regeneration, and with muscle cell differentiation in vitro.

    In summary, our studies show the importance of laminin-2 in skeletal muscle. We have provided new information on three markers for different stages of myogenic differentiation, laminin laminina2, laminina-sarcoglycan, and tetranectin. In addition, our studies contribute to a better understanding of the mechanism of human disease caused by laminin-2 deficiency.

  • 307.
    Kubrak, Olga I.
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Kucerova, Lucie
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Theopold, Ulrich
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Nylin, Sören
    Stockholm University, Faculty of Science, Department of Zoology.
    Nässel, Dick R.
    Stockholm University, Faculty of Science, Department of Zoology.
    Characterization of Reproductive Dormancy in Male Drosophila melanogaster2016In: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 7, article id 572Article in journal (Refereed)
    Abstract [en]

    Insects are known to respond to seasonal and adverse environmental changes by entering dormancy, also known as diapause. In some insect species, including Drosophila melanogaster, dormancy occurs in the adult organism and postpones reproduction. This adult dormancy has been studied in female flies where it is characterized by arrested development of ovaries, altered nutrient stores, lowered metabolism, increased stress and immune resistance and drastically extended lifespan. Male dormancy, however, has not been investigated in D. melanogaster, and its physiology is poorly known in most insects. Here we show that unmated 3-6 h old male flies placed at low temperature (11 degrees C) and short photoperiod (10 Light:14 Dark) enter a state of dormancy with arrested spermatogenesis and development of testes and male accessory glands. Over 3 weeks of diapause we see a dynamic increase in stored carbohydrates and an initial increase and then a decrease in lipids. We also note an up-regulated expression of genes involved in metabolism, stress responses and innate immunity. Interestingly, we found that male flies that entered reproductive dormancy do not attempt to mate females kept under non-diapause conditions (25 degrees C, 1 2L:1 2D), and conversely non-diapausing males do not mate females in dormancy. In summary, our study shows that male D. melanogaster can enter reproductive dormancy. However, our data suggest that dormant male flies deplete stored nutrients faster than females, studied earlier, and that males take longer to recover reproductive capacity after reintroduction to non-diapause conditions.

  • 308.
    Kugelberg, Otto
    Stockholm University.
    Food relations of a seed feeding insect, Lygaeus equestris (L.)(Heteroptera, Lygaeidae)1977Doctoral thesis, comprehensive summary (Other academic)
  • 309.
    Kullander, Sven O.
    Stockholm University.
    Taxonomic studies on the percoid freshwater fish family Cichlidae in South America1983Doctoral thesis, monograph (Other academic)
  • 310.
    Kullberg, Cecilia
    Stockholm University, Faculty of Science, Department of Zoology.
    Behaviour under predation risk in birds1998Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Predation is a major selective force in the evolution of both morphological and behavioural characters in animals. The flexibility in behavioural traits according to perceived predation risk has received much attention in recent years. Since resources often are limited, prey animals face a trade-off between the risk of predation and other energy demanding activities in life. This thesis investigates the effect of predation risk on some behavioural traits in birds. The two main topics under study are predation risk and niche use in the genus Parus, and mass-dependent predation risk in birds.

    In a field study investigating hunting behaviour in relation to prey choice in wild pygmy owls, Glaucidium passerinum, I found that when hunting for birds, owls used a hunting strategy attacking the birds with a height advantage from ambush. This observation suggests that birds foraging high in the tree and close to the trunk, sheltered by branches, face a lower predation risk than birds foraging further out and lower down in the tree. In a laboratory experiment with wild caught willow tits, Parus montanus, I investigated the use of foraging sites in the tree according to perceived predation risk. The tits adjusted foraging behaviour to the present predation risk by choosing more sheltered foraging sites after the presentation of a model raptor. Since the hunting strategy of pygmy owls lead to selective predation of birds foraging in the outer parts of branches, the pygmy owl might acts as a keystone predator enabling coexistence of tit species that are separated in their foraging niches. The coexistence of willow tits, crested tits, Parus cristatus, and coal tits, P. ater, could be a result of a two-way asymmetric interaction between species competing for food and predator safe foraging sites.

    Laboratory experiments investigating take-off ability in relation to diurnal body mass increase ((8%) in wintering willow tits and great tits, Parus major, showed no measurable effect on flight ability, indicating that the small energy reserves accumulated during a day in wintering tits do not increase predation risk as a consequence of reduced take-off ability. However in a similar experiment studying migratory fuel load (up to 59% of lean body mass) in blackcaps, Sylvia atricapilla, a reduction in both velocity and angle of ascent was found suggesting that the large fuel loads needed for migration place the birds at an increased risk of predation. The study of alarmed take-off flights in great tits further suggests that great tits adjust take-off strategy to the attack trajectory of an attacking raptor, indicating that the trade-off between velocity and angle of ascent during take-off is affected by the nature of the predator attack.

  • 311.
    Kullberg, Cecilia
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology.
    Kaby, Ulrika
    Stockholm University, Faculty of Science, Department of Zoology.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    Impaired flight ability prior to egg laying: A cost of being a capital breeder2005In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 19, no 1, p. 98-101Article in journal (Refereed)
    Abstract [en]
    • 1To investigate flight ability in captive Zebra Finches during reproduction we compared change in escape take-off ability and wing load of reproducing females with their mates and non-reproducing females when attacked by a model raptor.
    • 2Initially females had 18% higher wing load than males. Non-reproducing females and females that had started egg-laying flew slower than males. Reproducing females reduced wing load during egg-laying and flew faster when the clutch was completed. Non-breeding females remained on high wing load and flow slower than breeding females that had completed their clutch.
    • 3The increase in flight speed of breeding females was explained by a reduction in wing load during egg-laying.
    • 4Zebra Finches use accumulated reserves to produce eggs and pay a cost in terms of reduced flight ability, but then regain flight performance when the clutch is laid, probably demonstrating a predation cost of capital breeding in birds.
  • 312.
    Kullberg, Cecilia
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    An experimental study of predator recognition in great tit fledglings2002In: Ethology, ISSN 0179-1613, E-ISSN 1439-0310, Vol. 108, no 5, p. 429-441Article in journal (Refereed)
    Abstract [en]

    Studies of naturally predator-naïve adult birds (finches on predator-free islands) and birds experimentally hand reared in isolation from predators indicate that birds can recognise predators innately; that is, birds show anti-predator behaviour without former experience of predators. To reduce predation risk efficiently during the vulnerable fledgling period, we would predict an innate response to be fully developed when the chicks leave the nest. However, 30-day-old naïve great tit fledglings (Parus major) did not respond differently to a model of a perched predator than to a similarly sized model of a non-predator. Although chicks showed distress responses such as warning calls and freezing behaviour, they did not differentiate between the stimuli. In contrast, wild-caught first-year birds (4 mo old) and adults responded differentially to the two stimuli. Lack of recognition of a perched predator might be one explanation for the high mortality rate found in newly fledged great tits. Our results imply that parental care is not only important for food provisioning, but also to reduce predation risk during the time when fledglings are most vulnerable

  • 313.
    Kullberg, Cecilia
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    Fransson, Thord
    Naturhistoriska Riksmuseet.
    Vallin, Adrian
    Stockholm University, Faculty of Science, Department of Zoology.
    Magnetic cues and time of season affect fuel deposition in migratory thrush nightingales (Luscinia luscinia)2003In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 270, no 1513, p. 373-378Article in journal (Refereed)
    Abstract [en]

    Bird migration requires high energy expenditure, and long–distance migrants accumulate fat for use as fuel during stopovers throughout their journey. Recent studies have shown that long–distance migratory birds, besides accumulating fat for use as fuel, also show adaptive phenotypic flexibility in several organs during migration. The migratory routes of many songbirds include stretches of sea and desert where fuelling is not possible. Large fuel loads increase flight costs and predation risk, therefore extensive fuelling should occur only immediately prior to crossing inhospitable zones. However, despite their crucial importance for the survival of migratory birds, both strategic refuelling decisions and variation in phenotypic flexibility during migration are not well understood. First–year thrush nightingales (Luscinia luscinia) caught in the early phase of the onset of autumn migration in southeast Sweden and exposed to a magnetic treatment simulating a migratory flight to northern Egypt increased more in fuel load than control birds. By contrast, birds trapped during the late phase of the onset of autumn migration accumulated a high fuel load irrespective of magnetic treatment. Furthermore, early birds increased less in flight–muscle size than birds trapped later in autumn. We suggest that the relative importance of endogenous and environmental factors in individual birds is affected by the time of season and by geographical area. When approaching a barrier, environmental cues may act irrespective of the endogenous time programme.

  • 314.
    Kvarnemo, C.
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Mobley, K. B.
    Partridge, C.
    Jones, A. G.
    Ahnesjo, I.
    Evidence of paternal nutrient provisioning to embryos in broad-nosed pipefish Syngnathus typhle2011In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 78, no 6, p. 1725-1737Article in journal (Refereed)
    Abstract [en]

    In two experiments, radioactively labelled nutrients (either (3)H-labelled amino-acid mixture or (14)C-labelled glucose) were tube-fed to brooding male Syngnathus typhle. Both nutrients were taken up by the males and radioactivity generally increased in the brood pouch tissue with time. Furthermore, a low but significant increase of (3)H-labelled amino acids in embryos was found over the experimental interval (48 h), whereas in the (14)C-glucose experiment the radioactivity was taken up by the embryos but did not increase over the experimental time (320 min). Uptake of radioisotopes per embryo did not differ with embryo size. A higher uptake mg(-1) tissue of both (3)H-labelled amino acids and (14)C-labelled glucose was found in smaller embryos, possibly due to a higher relative metabolic rate or to a higher surface-area-to-volume ratio compared to larger embryos. Uptake in embryos was not influenced by male size, embryonic developmental advancement or position in the brood pouch. It is concluded that brooding males provide amino acids, and probably also glucose, to the developing embryos in the brood pouch. (C) 2011 The Authors Journal of Fish Biology (C) 2011 The Fisheries Society of the British Isles

  • 315.
    Kånneby, Tobias
    Stockholm University, Faculty of Science, Department of Zoology, Systematic Zoology.
    New species and new records of freshwater Chaetonotida (Gastrotricha) from Sweden2011In: Zootaxa, ISSN 1175-5326, E-ISSN 1175-5334, Vol. 3115, p. 29-55Article in journal (Refereed)
    Abstract [en]

    Gastrotricha is a small phylum of acoelomatic aquatic invertebrates common in both marine and freshwater environments. The freshwater gastrotrich fauna of Sweden is poorly known and to date only twenty species have been reported. In this study two species of the genus Heterolepidoderma: Heterolepidoderma joermungandri n. sp. and H. trapezoidum n. sp. are described as new to science. Moreover nine species are presented as new to the Swedish fauna. Additional taxonomic information is also given for four species previously reported from the country. In total 7 genera spanning two families, Chaetonotidae and Dasydytidae, are presented and the number of reported freshwater gastrotrichs from the country is increased to 31.

  • 316.
    Kånneby, Tobias
    et al.
    The Swedish Museum of Natural History .
    Todaro, M. Antonio
    Jondelius, Ulf
    The Swedish Museum of Natural History.
    A Phylogenetic approach to species delimitation in freshwater Gastrotricha from Sweden2012In: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 683, no 1, p. 185-202Article in journal (Refereed)
    Abstract [en]

    Gastrotricha is a cosmopolitan group of aquatic invertebrates. To date approximately 765 species have been described. This study is the first to deal with species delimitation and cryptic species of freshwater Gastrotricha. Three commonly encountered species, Heterolepidoderma ocellatum, Lepidochaetus zelinkai and Lepidodermella squamata, are investigated for cryptic speciation. Most of the material is based on Swedish specimens but closely related species from other parts of the world are also included. Taxonomic revisions are supported by phylogenies based on 18S rRNA, 28S rRNA and COI mtDNA of freshwater Chaetonotidae from several genera and inferred from Bayesian and maximum likelihood approaches. Heterolepidoderma ocellatum f. sphagnophilum is raised to species level, becoming H. acidophilum n. sp. Moreover, genetic data based on COI indicates high variation between two morphologically very similar groups of Lepidodermella squamata. The extent of cryptic speciation in L. zelinkai appears low. Based on the phylogenetic hypothesis presented in this paper the new species, Lepidodermella intermedia n. sp., from northernSweden is also described. The phylogenetic hypothesis generated show that Chaetonotidae is a non-monophyletic group.  

  • 317.
    Kånneby, Tobias
    et al.
    Naturhistoriska riksmuseet, Enheten för evertebratzoologi.
    Todaro, M. Antonio
    Jondelius, Ulf
    Naturhistoriska riksmuseet, enheten för evertebratzoologi.
    One new species and records of Ichthydium Ehrenberg, 1830 (Gastrotricha: Chaetonotida) from Sweden with a key to the genus2009In: Zootaxa, ISSN 1175-5326, E-ISSN 1175-5334, no 2278, p. 26-46Article in journal (Refereed)
    Abstract [en]

    The freshwater gastrotrich fauna of Sweden is poorly known. Only seven species of freshwater gastrotrichs have been reported so far. This paper is the first in a series of contributions about the Swedish freshwater gastrotrich fauna. Here we describe one new species, Ichthydium skandicum n. sp., from Jamtland, northern Sweden. The new species falls within the boundary of the subgenus Forficulichthys and is morphologically closest to Ichthydium tanytrichum from which it can be differentiated based on the presence of four pairs of dorsal, keeled scales in the posterior trunk region. Moreover, we provide morphometric data for three additional Ichthydium species: I. diacanthum, I. squamigerum and I. tanytrichum, Italian species all of which are reported for the first time outside Italy. Considering the accompanying fauna, a total of thirteen freshwater Gastrotricha are reported for the first time from Sweden. Finally we present a dichotomous key for Ichthydium along with distributional data of the species considered.

  • 318.
    Kånneby, Tobias
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Systematic Zoology.
    Todaro, M. Antonio
    Jondelius, Ulf
    Stockholm University, Faculty of Science, Department of Zoology, Systematic Zoology.
    Phylogeny of Chaetonotidae (Gastrotricha) inferred from nuclear and mitochondrial genesManuscript (preprint) (Other academic)
    Abstract [en]

    Chaetonotidae is the largest family within Gastrotricha with almost 400 nominal species, represented in both freshwater and marine habitats. The group is probably non-monophyletic and suffers from a troubled taxonomy. Current classification is to a great extent based on shape and distribution of cuticular structures, characters that are highly variable. We present the most densely sampled molecular study so far where 17 out of 31 genera belonging to Chaetonotida are represented. Bayesian and maximum likelihood approaches based on 18S rDNA, 28S rDNA and COI mtDNA are used to reconstruct relationships within Chaetonotidae. The use of cuticular structures for supra-specific classification within the group is evaluated and the question of dispersal between marine and freshwater habitats is addressed. Moreover the subgeneric classification of Chaetonotus is tested in a phylogenetic context. Our results show high support for a clade containing Dasydytidae nested within Chaetonotidae. Within this clade only 3 genera are monophyletic following current classification. Genera containing both marine and freshwater species never form monophyletic clades and group with other species according to habitat. Marine members of Aspidiophorus appear to be the sister group of all other Chaetonotidae and Dasydytidae, indicating a marine origin of the clade. Halichaetonotus and marine Heterolepidoderma form a monophyletic group in a sister group relationship to freshwater species, pointing towards a secondary invasion to marine environments of these taxa. Our study shows the problems of current classification based on cuticular structures, characters that show homoplasy for deeper relationships.

  • 319. Küker, Susanne
    et al.
    Huber, Nikolaus
    Evans, Alina
    Kjellander, Petter
    Bergvall, Ulrika A
    Department of Ecology, Swedish University of Agricultural Sciences, Grimsö Wildlife Research Station, Riddarhyttan, Sweden.
    Jones, Krista L
    Arnemo, Jon M
    Hematology, serum chemistry, and serum protein electrophoresis ranges for free-ranging roe deer (Capreolus capreolus) in Sweden.2015In: Journal of Wildlife Diseases, ISSN 0090-3558, E-ISSN 1943-3700, Vol. 51, no 1, p. 269-73Article in journal (Refereed)
    Abstract [en]

    We present the first reference ranges for hematology (n = 35 animals), serum biochemistry (n = 62), and serum protein electrophoresis (n = 32) in physically restrained free-ranging roe deer (Capreolus capreolus). Animals were captured in box traps and physically restrained for blood sampling during the winter in Sweden, 2011-13. No clinically significant sex or age differences were found.

  • 320.
    Lagerholm, Vendela K.
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. Swedish Museum of Natural History, Sweden; University of St Andrews, UK.
    Norén, Karin
    Stockholm University, Faculty of Science, Department of Zoology. University of California Davis, USA.
    Ehrich, Dorothee
    Ims, Rolf A.
    Killengreen, Siw T.
    Abramson, Natalia I.
    Niemaa, Jukka
    Angerbjörn, Anders
    Stockholm University, Faculty of Science, Department of Zoology.
    Henttonen, Heikki
    Dalén, Love
    Run to the hills: gene flow among mountain areas leads to low genetic differentiation in the Norwegian lemming2017In: Biological Journal of the Linnean Society, ISSN 0024-4066, E-ISSN 1095-8312, Vol. 121, no 1, p. 1-14Article in journal (Refereed)
    Abstract [en]

    The endemic Norwegian lemming (Lemmus lemmus) is an icon for cyclic species, famous since the Middle Ages for its enormous population outbreaks and mass movements. Although the drivers behind this cyclicity have been intensively investigated, virtually nothing is known about the extent to which long-distance dispersal during population peaks actually lead to gene flow among mountain tundra areas. In this article, we use nine microsatellite markers to address this question and analyse range-wide genetic diversity and differentiation between Fennoscandian sub-regions. The results revealed a high genetic variation with a surprisingly weak population structure, comparable to that of much larger mammals. The differentiation was mainly characterized as a genetic cline across the species' entire distribution, and results from spatial autocorrelation analyses suggested that gene flow occurs with sufficiently high frequency to create a genetic patch size of 100 km. Further, we found that for the equivalent distances, the southern sub-regions were genetically more similar to each other than those in the north, which indicates that the prolonged periods of interrupted lemming cyclicity recorded in the northern parts of Fennoscandia have led to increased isolation and population differentiation. In summary, we propose that mass movements during peak years act as pulses of gene flow between mountain tundra areas, and that these help to maintain genetic variation and counteract differentiation over vast geographic distances.

  • 321.
    Lagerholm, Vendela K.
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. Swedish Museum of Natural History, Sweden.
    Sandoval-Castellanos, Edson
    Stockholm University, Faculty of Science, Department of Zoology. Swedish Museum of Natural History, Sweden.
    Ehrich, Dorothee
    Abramson, Natalia I.
    Nadachowski, Adam
    Kalthoff, Daniela C.
    Germonpre, Mietje
    Angerbjörn, Anders
    Stockholm University, Faculty of Science, Department of Zoology.
    Stewart, John R.
    Dalén, Love
    On the origin of the Norwegian lemming2014In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 23, no 8, p. 2060-2071Article in journal (Refereed)
    Abstract [en]

    The Pleistocene glacial cycles resulted in significant changes in species distributions, and it has been discussed whether this caused increased rates of population divergence and speciation. One species that is likely to have evolved during the Pleistocene is the Norwegian lemming (Lemmus lemmus). However, the origin of this species, both in terms of when and from what ancestral taxon it evolved, has been difficult to ascertain. Here, we use ancient DNA recovered from lemming remains from a series of Late Pleistocene and Holocene sites to explore the species' evolutionary history. The results revealed considerable genetic differentiation between glacial and contemporary samples. Moreover, the analyses provided strong support for a divergence time prior to the Last Glacial Maximum (LGM), therefore likely ruling out a postglacial colonization of Scandinavia. Consequently, it appears that the Norwegian lemming evolved from a small population that survived the LGM in an ice-free Scandinavian refugium.

  • 322.
    Laikre, Linda
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Jansson, Mija
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Allendorf, Fred W.
    Jakobsson, Sven
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Ryman, Nils
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Hunting Effects on Favourable Conservation Status of Highly Inbred Swedish Wolves2013In: Conservation Biology, ISSN 0888-8892, E-ISSN 1523-1739, Vol. 27, no 2, p. 248-253Article in journal (Refereed)
    Abstract [en]

    The wolf (Canis lupus) is classified as endangered in Sweden by the Swedish Species Information Centre, which is the official authority for threat classification. The present population, which was founded in the early 1980s, descends from 5 individuals. It is isolated and highly inbred, and on average individuals are more related than siblings. Hunts have been used by Swedish authorities during 2010 and 2011 to reduce the population size to its upper tolerable level of 210 wolves. European Union (EU) biodiversity legislation requires all member states to promote a concept called “favourable conservation status” (FCS) for a series of species including the wolf. Swedish national policy stipulates maintenance of viable populations with sufficient levels of genetic variation of all naturally occurring species. Hunting to reduce wolf numbers in Sweden is currently not in line with national and EU policy agreements and will make genetically based FCS criteria less achievable for this species. We suggest that to reach FCS for the wolf in Sweden the following criteria need to be met: (1) a well-connected, large, subdivided wolf population over Scandinavia, Finland, and the Russian Karelia-Kola region should be reestablished, (2) genetically effective size (Ne) of this population is in the minimum range of Ne = 500–1000, (3) Sweden harbors a part of this total population that substantially contributes to the total Ne and that is large enough to not be classified as threatened genetically or according to IUCN criteria, and (4) average inbreeding levels in the Swedish population are <0.1.

  • 323.
    Laikre, Linda
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Larsson, Lena C.
    Stockholm University, Faculty of Science, Department of Zoology.
    Palmé, Anna
    Stockholm University, Faculty of Science, Department of Zoology.
    Charlier, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    Josefsson, Melanie
    Ryman, Nils
    Stockholm University, Faculty of Science, Department of Zoology.
    Potentials for monitoring gene level biodiversity: using Sweden as an example2008In: Biodiversity and Conservation, ISSN 0960-3115, E-ISSN 1572-9710, Vol. 17, no 4, p. 893-910Article in journal (Refereed)
    Abstract [en]

    Programs for monitoring biological diversity over time are needed to detect changes that can constitute threats to biological resources. The convention on biological diversity regards effective monitoring as necessary to halt the ongoing erosion of biological variation, and such programs at the ecosystem and species levels are enforced in several countries. However, at the level of genetic biodiversity, little has been accomplished, and monitoring programs need to be developed. We define “conservation genetic monitoring” to imply the systematic, temporal study of genetic variation within particular species/populations with the aim to detect changes that indicate compromise or loss of such diversity. We also (i) identify basic starting points for conservation genetic monitoring, (ii) review the availability of such information using Sweden as an example, (iii) suggest categories of species for pilot monitoring programs, and (iv) identify some scientific and logistic issues that need to be addressed in the context of conservation genetic monitoring. We suggest that such programs are particularly warranted for species subject to large scale enhancement and harvest—operations that are known to potentially alter the genetic composition and reduce the variability of populations.

  • 324.
    Laikre, Linda
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Nilsson, T
    Länsstyrelsen Värmland.
    Primmer, CR
    University of Turku, Finland.
    Ryman, Nils
    Stockholm University, Faculty of Science, Department of Zoology.
    Allendorf, FW
    University of Montana, USA.
    Importance of Genetics in the Interpretation of Favourable Conservation Status2009In: Conservation Biology, ISSN 0888-8892, E-ISSN 1523-1739, Vol. 23, p. 1378-1381Article in journal (Refereed)
    Abstract [en]

    “Favourable Conservation Status” (FCS) is a central concept in the biodiversity conservation legislation of the European Union (EU). Here, we highlight the importance of incorporating aspects of conservation genetics in interpretation of this concept. Recent documents from the EU Commission indicate that knowledge of conservation genetics has so far been lacking among those who have tried to employ the concept. We think it is crucial that aspects of conservation genetics be incorporated in discussion of this concept and that this be done before the EU Court of Justice takes a position on the legal interpretation of FCS.

  • 325.
    Laikre, Linda
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Palmé, Anna
    Stockholm University, Faculty of Science, Department of Zoology.
    Larsson, Lena C
    Stockholm University, Faculty of Science, Department of Zoology.
    Charlier, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    Ryman, Nils
    Stockholm University, Faculty of Science, Department of Zoology.
    Effekter av spridning av genetiskt främmande populationer: en kartläggning av förutsättningarna för uppföljande studier av utsättningar av djur och växter i Sverige2008Report (Other academic)
  • 326. Lamichhaney, Sangeet
    et al.
    Barrio, Alvaro Martinez
    Rafati, Nima
    Sundström, Görel
    Rubin, Carl-Johan
    Gilbert, Elizabeth R.
    Berglund, Jonas
    Wetterbom, Anna
    Laikre, Linda
    Stockholm University, Faculty of Science, Department of Zoology.
    Webster, Matthew T.
    Grabherr, Manfred
    Ryman, Nils
    Stockholm University, Faculty of Science, Department of Zoology.
    Andersson, Leif
    Population-scale sequencing reveals genetic differentiation due to local adaptation in Atlantic herring2012In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 109, no 47, p. 19345-19350Article in journal (Refereed)
    Abstract [en]

    The Atlantic herring (Clupea harengus), one of the most abundant marine fishes in the world, has historically been a critical food source in Northern Europe. It is one of the few marine pecies that can reproduce throughout the brackish salinity gradient of the Baltic Sea. Previous studies based on few genetic markers have revealed a conspicuous lack of genetic differentiation between geographic regions, consistent with huge population sizes and minute genetic drift. Here, we present a cost-effective genome-wide study in a species that lacks a genome sequence. We first assembled a muscle transcriptome and then aligned genomic reads to the transcripts, creating an “exome assembly,” capturing both exons and flanking sequences. We then resequenced pools of fish from a wide geographic range, including the Northeast Atlantic, as well as different regions in the Baltic Sea, aligned the reads to the exome assembly, and identified 440,817 SNPs. The great majority of SNPs showed no appreciable differences in allele frequency among populations; however, several thousand SNPs showed striking differences, some approaching fixation for different alleles. The contrast between low genetic differentiation at most loci and striking differences at others implies that the latter category primarily reflects natural selection. A simulation study confirmed that the distribution of the fixation index FST deviated significantly from expectation for selectively neutral loci. This study provides insights concerning the population  structure of an important marine fish and establishes the Atlantic herring as a model for population genetic studies of adaptation and natural selection.

  • 327. Landergren, Peter
    Sea trout, Salmo trutta L., in small streams on Gotland: the coastal zone as a growth habitat for parr2001Doctoral thesis, comprehensive summary (Other academic)
  • 328.
    Landin, Jan
    Stockholm University.
    Habitats, life histories, migration and dispersal by flight in water beetles (Hydrophilidae and Hydraenidae)1980Doctoral thesis, comprehensive summary (Other academic)
  • 329.
    Lange, Henrik
    Stockholm University, Faculty of Science, Department of Zoology.
    Social dominance and agonistic communication in the great tit2003Doctoral thesis, comprehensive summary (Other academic)
  • 330.
    Lappalainen, Annikki
    Stockholm University.
    On the ecology of shallow sandy bottoms in the Baltic Sea with special reference to mud snails (Hydrobiidae)1980Doctoral thesis, comprehensive summary (Other academic)
  • 331.
    Larsdotter Mellström, Helena
    Stockholm University, Faculty of Science, Department of Zoology.
    A life history perspective on mating behaviour in the butterfly Pieris napi2009Licentiate thesis, comprehensive summary (Other academic)
  • 332.
    Larsdotter Mellström, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Friberg, Magne
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Borg-Karlson, Anna-Karin
    KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry.
    Murtazina, Rushana
    KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry.
    Palm, Mikael
    KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    Seasonal polyphenism in life history traits: Time costs of direct development in a butterfly2010In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 64, p. 1377-1383Article in journal (Refereed)
    Abstract [en]

    Insects with two or more generations per year will generally experience different selection regimes depending on the season, and accordingly show seasonal polyphenisms. In butterflies, seasonal polyphenism has been shown with respect to morphology, life history characteristics and behaviour. In temperate bivoltine species, the directly developing generation is more time-constrained than the diapause generation and this may affect various life history traits, such as mating propensity (time from eclosion to mating). Here we test whether mating propensity differs between generations in Pieris napi, along with several physiological parameters, for males sex pheromone synthesis, and for females ovigeny index and fecundity.

    As predicted, individuals of the directly developing generation – who have shorter time for pupal development - are more immature at eclosion; males take longer to synthesize the male sex pheromone after eclosion and also take longer to mate than diapause generation males. Females show the same physiological pattern, the directly developing females lay fewer eggs than diapausing females during the first days of their life. Nevertheless, the directly developing females mate faster after eclosion than diapausing females, indicating substantial adult time stress in this generation and possibly an adaptive value of shortening the pre-reproductive period.

    Our study highlights how time-stress can be predictably different between generations, affecting both life history and behaviour. By analyzing several life history traits simultaneously we adopt a multi-trait approach to examining how adaptations and developmental constraints likely interplay to shape these seasonal polyphenisms.

  • 333.
    Larsdotter Mellström, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Males use sex pheromone assessment to tailor ejaculates to risk of sperm competition in a butterfly2009In: Behavioral Ecology, ISSN 1045-2249, E-ISSN 1465-7279, Vol. 20, no 5, p. 1147-1151Article in journal (Refereed)
    Abstract [en]

    In polyandrous butterflies males transfer a large, nutritious ejaculate at mating. Larger ejaculates delay female remating and confer an advantage in sperm competition. However, large ejaculates are costly, potentially selecting for male adjustment of ejaculate size to the risk of sperm competition. Here, we test if male ejaculate size in the butterfly Pieris napi varies with male density, and whether males assess sperm competition risk using the male sex pheromone citral as a cue. The results conform to sperm competition theory and showed that male P. napi tailored their reproductive investment in response to the risk of sperm competition; ejaculates transferred by males in the high male density treatments were on average 23% larger than ejaculates transferred at low male densities. The results also show for the first time, that the sex pheromone citral was used by males to assess male density; ejaculates transferred by males in presence of added male sex-pheromone were 19% larger than ejaculates transferred in the control. In conclusion, the study shows how the sex pheromone not only facilitates female acceptance when dispensed by courting males, but also allows males to assess the degree of male competition for matings.

  • 334.
    Larsdotter Mellström, Helena
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology.
    What affects mating rate?: Polyandry is higher in the directly developing generation of the butterfly Pieris napi2010In: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 80, p. 413-418Article in journal (Refereed)
    Abstract [en]

    Polyandry is common among insects and female insects in general gain directly from mating multiply in terms of increased lifetime reproductive success. Nevertheless, polyandry is not rampant, suggesting that realized polyandry is the outcome of costs and benefits associated with multiple matings. In the bivoltine green-veined white butterfly Pieris napi, females gain from mating multiply as males transfer a substantial nuptial gift along with the sperm at mating. Nonetheless, lifetime number of matings varies between 1 and 6 and 12 % of females mate only once. Here, we explore the reason for this variation and test (1) whether female polyandry is contingent on environmental conditions, specifically whether females can compensate for adverse conditions by mating more often, and (2) whether the level of polyandry differs between the diapausing generation that flies after pupal hibernation, and the directly developing generation, specifically whether females in the more time-constrained summer generation are more polyandrous, possibly as a result of selection for early high mating propensity and thereby shorter pre-reproductive period. Results showed that (1) females do not compensate for adverse conditions by mating more often, and (2) the level of polyandry was higher in the directly developing generation than in the diapause generation. Hence, we argue that differences in time stress and mating propensity between generations interplay in shaping mating frequency, and that the difference in polyandry between generations highlights the importance of integrating developmental pathway and life history.

  • 335.
    Larsson, Håkan
    Stockholm University, Faculty of Science, The Wenner-Gren Institute.
    Profilactin and the regulation of actin assembly and disassembly1985Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Actin filament assembly and disassembly are believed to be fundamental steps in the mechanism of cell motility in non-muscle cells. Profilactin is a complex between monomeric actin and a small protein, profilin, which inhibits the polymerization of the actin. It is assumed that profilactin is an unpolymerized storage form of actin in the cell and that profilin is of central importance to the regulation of actin physiology. Previously, biochemical characterization of calf spleen profilactin has been difficult because of a disturbing variability in the stability between different preparations of the complex.

    This thesis demonstrates that the major reason for the variation in the stability of profilactin was the presence of minute amounts of contaminating protein factors that affect actin polymerization, presumably by binding specifically to one of the ends of the actin polymer. Conditions for the removal of these contaminating factors have been worked out and for the isolation of intact homogeneous profilin and actin. It is shown that the properties of the reconstituted complex are essentially the same as those of the isolated 'native' complex. The effects of profilin on spleen actin assembly and disassembly have been studied and apparent dissociation constants have been determined for the spleen complex as well as for the heterologous complex formed between spleen profilin and actin isolated from rabbit skeletal muscle. Finally, it has been shown that the spleen proteins, both separately and as a complex, specifically interact with detergents and the hydrophobic probe DPH.

  • 336.
    Larsson, Lena C.
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Charlier, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    Laikre, Linda
    Stockholm University, Faculty of Science, Department of Zoology.
    Ryman, Nils
    Stockholm University, Faculty of Science, Department of Zoology.
    Statistical power for detecting genetic divergence–organelle versus nuclear markers2009In: Conservation Genetics, ISSN 1566-0621, E-ISSN 1572-9737, Vol. 10, no 5, p. 1255-1264Article in journal (Refereed)
    Abstract [en]

    Statistical power is critical in conservation for detecting genetic differences in space or time from allele frequency data. Organelle and nuclear genetic markers have fundamentally different transmission dynamics; the potential effect of these differences on power to detect divergence have been speculated on but not investigated. We examine, analytically and with computer simulations, the relative performance of organelle and nuclear markers under basic, ideal situations. We conclude that claims of a generally higher resolving power of either marker type are not correct. The ratio R = FST,organelle/FST,nuclear varies between 1 and 4 during differentiation and this greatly affects the power relationship. When nuclear FST is associated with organelle differentiation four times higher, the power of the organelle marker is similar to two nuclear loci with the same allele frequency distribution. With large sample sizes (n C 50) and several populations or many alleles per locus (C5), the power difference may typically be disregarded when nuclear FST[0.05. To correctly interpret observed patterns of genetic differentiation in practical situations, the expected FSTs and the statistical properties (i.e., power analysis) of the genetic markers used should be evaluated, taking the observed allele frequency distributions into consideration.

  • 337.
    Larsson, Per-Olov
    Stockholm University.
    Some characteristics of the Baltic salmon (Salmo salar) L., population: individual growth, exploitation pattern and total mortality, from the smolt stage, as revealed by Swedish smolt taggings1983Doctoral thesis, comprehensive summary (Other academic)
  • 338.
    Larsson, Ulf
    Stockholm University.
    The pelagic microheterotrophic food web in the Baltic Sea: bacteria and their dependence on phytoplankton1986Doctoral thesis, comprehensive summary (Other academic)
  • 339. Lecoeur, Julien
    et al.
    Dacke, Marie
    Floreano, Dario
    Baird, Emily
    Stockholm University, Faculty of Science, Department of Zoology. Lund University, Sweden.
    The role of optic flow pooling in insect flight control in cluttered environments2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 7707Article in journal (Refereed)
    Abstract [en]

    Flight through cluttered environments, such as forests, poses great challenges for animals and machines alike because even small changes in flight path may lead to collisions with nearby obstacles. When flying along narrow corridors, insects use the magnitude of visual motion experienced in each eye to control their position, height, and speed but it is unclear how this strategy would work when the environment contains nearby obstacles against a distant background. To minimise the risk of collisions, we would expect animals to rely on the visual motion generated by only the nearby obstacles but is this the case? To answer this, we combine behavioural experiments with numerical simulations and provide the first evidence that bumblebees extract the maximum rate of image motion in the frontal visual field to steer away from obstacles. Our findings also suggest that bumblebees use different optic flow calculations to control lateral position, speed, and height.

  • 340.
    Lehmann, Philipp
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. University of Jyväskylä, Finland.
    Kaunisto, Sirpa
    Kostal, Vladimir
    Margus, Aigi
    Zahradnickova, Helena
    Lindström, Leena
    Comparative Ecophysiology of Cold-Tolerance-Related Traits: Assessing Range Expansion Potential for an Invasive Insect at High Latitude2015In: Physiological and Biochemical Zoology, ISSN 1522-2152, E-ISSN 1537-5293, Vol. 88, no 3, p. 254-265Article in journal (Refereed)
    Abstract [en]

    Survival at high latitude requires the capability to cope with seasonally imposed stress, such as low winter temperatures or large temperature fluctuations. The Colorado potato beetle, Leptinotarsa decemlineata, is an invasive pest of potato that has rapidly spread from low latitudes to higher latitudes. During the last 30 years, a decrease in range expansion speed is apparent in Europe. We use a comparative approach to assess whether this could be due to an inability of L. decemlineata to cope with the harsher winters encountered at high latitude, when compared to two native northern chrysomelid beetles with similar overwintering ecology. We investigated several cold-tolerance-related physiological traits at different time points during winter. Cold tolerance followed a latitudinal pattern; the northern species were more tolerant to short-term subzero temperatures than the invasive L. decemlineata. The other northern species, the knotgrass leaf beetle, Chrysolina polita, was found to tolerate internal freezing. Interestingly, the pattern for overwinter survival at 5 degrees C was the opposite and higher in L. decemlineata than the northern species and could be related to behavioral differences between species in overwintering location selection and a potential physiological trade-off between tolerance to cold shock and to chronic cold exposure. Furthermore, while the northern species accumulated large amounts of different sugars and polyols with probable cryoprotectant functions, none were detected in L. decemlineata at high concentrations. This lack of cryoprotectant accumulation could explain the difference in cold tolerance between the species and also suggests that a lack of physiological capacity to tolerate low temperatures could slow further latitudinal range expansion of L. decemlineata.

  • 341.
    Lehmann, Philipp
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. University of Jyväskylä, Finland.
    Lyytinen, Anne
    Piiroinen, Saija
    Lindström, Leena
    Is a change in juvenile hormone sensitivity involved in range expansion in an invasive beetle?2015In: Frontiers in Zoology, ISSN 1742-9994, E-ISSN 1742-9994, Vol. 12, article id 20Article in journal (Refereed)
    Abstract [en]

    Introduction: It has been suggested that rapid range expansion could proceed through evolution in the endocrinological machinery controlling life-history switches. Based on this we tested whether the Colorado potato beetle, Leptinotarsa decemlineata, which has rapidly expanded its range across latitudinal regions in Europe, and shows photoperiodic adaptation in overwintering initiation, has different sensitivities to juvenile hormone (JH) manipulation along a latitudinal gradient. Results: A factorial experiment where beetles were reared either under a long or short day photoperiod was performed. Hormone levels were manipulated by topical applications. An allatostatin mimic, H17, was used to decrease and a juvenile hormone III analogue, pyriproxyfen, was used to increase the hormone levels. The effects of photoperiod and hormone manipulations on fecundity and overwintering related burrowing were monitored. Application of H17 decreased fecundity but did not induce overwintering related burrowing. Manipulation with pyriproxyfen increased fecundity and delayed burrowing. While small population-dependent differences in responsiveness to the topical application treatments were observed in fecundity, none were seen in overwintering related burrowing. Conclusions: The results indicate that the rapid photoperiodic adaptation manifested in several life-history and physiological traits in L. decemlineata in Europe is unlikely a result of population dependent differences in JH III sensitivity. While other endocrine factors cannot be ruled out, more likely mechanisms could be genetic changes in upstream elements, such as the photoperiodic clock or the insulin signaling pathway.

  • 342.
    Leimar, Olof
    Stockholm University, Faculty of Science, Department of Zoology.
    Evolutionary analysis of animal fighting1988Doctoral thesis, comprehensive summary (Other academic)
  • 343.
    Leimar, Olof
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Norberg, Ulf
    Stockholm University, Faculty of Science, Department of Zoology, Ethology.
    Wiklund, Christer
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Habitat preference and habitat exploration in two species of satyrine butterflies2003In: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 26, p. 474-480Article in journal (Refereed)
  • 344.
    Leimar, Olof
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Sasaki, Akira
    Doebeli, Michael
    Dieckmann, Ulf
    Limiting similarity, species packing, and the shape of competition kernels2013In: Journal of Theoretical Biology, ISSN 0022-5193, E-ISSN 1095-8541, Vol. 339, p. 3-13Article in journal (Refereed)
    Abstract [en]

    A traditional question in community ecology is whether species' traits are distributed as more-or-less regularly spaced clusters. Interspecific competition has been suggested to play a role in such structuring of communities. The seminal theoretical work on limiting similarity and species packing, presented four decades ago by Robert MacArthur, Richard Levins and Robert May, has recently been extended. There is now a deeper understanding of how competitive interactions influence community structure, for instance, how the shape of competition kernels can determine the clustering of species' traits. Competition is typically weaker for greater phenotypic difference, and the shape of the dependence defines a competition kernel. The clustering tendencies of kernels interact with other effects, such as variation in resource availability along a niche axis, but the kernel shape can have a decisive influence on community structure. Here we review and further extend the recent developments and evaluate their importance.

  • 345.
    Liao, Sifang
    Stockholm University, Faculty of Science, Department of Zoology.
    The role of insulin signaling during development, reproductive diapause and aging in Drosophila Melanogaster2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The insulin/insulin-like growth factor signaling pathway exists from invertebrates to vertebrates and it can regulate various biological processes, including development, metabolism, stress resistance and lifespan. In Drosophila, eight insulin-like peptides (DILP1-8) have been found. The specific function of each DILP is not fully known, especially for DILP1. In paper I, we found that dilp1 is specifically expressed in the brain insulin producing cells (IPCs), and it is mainly expressed from early pupa until few days of adult life, which correspond to non-feeding stages. The expression of dilp1 can last for at least 9 weeks of adult life when newborn virgin flies are induced to enter reproductive diapause. In addition, we found that the expression of dilp1 is under regulation by other dilps. Also larva-derived fat body, short neuropeptide F (sNPF) and juvenile hormone can affect dilp1 expression. We found that mutation of dilp1 affects female reproduction and starvation resistance. In paper II, we found that reproductive diapause can extend Drosophila life span, and at the same time ameliorate behavioral senescence, including negative geotaxis, activity rhythms and exploratory walking. Age-related changes in neuromuscular junction (NMJ) in abdominal muscle cannot be found in diapause-induced aging flies. The levels of several neuromodulators in the brain, including pigment dispersion factor (PDF), tyrosine hydroxylase (TH) and short neuropeptide F (sNPF), decreased significantly in normally aging flies, but less so in diapausing flies. In paper III, we show that mutation of dilp1 leads to a reduced organismal bodyweight, whereas overexpression increases it during the nonfeeding pupal stage. Overexpression of dilp1 additionally increases body size of flies, but reduces stores of larval-derived energy. This results in decreased starvation tolerance and increased feeding in newborn flies. In paper IV, we found that dilp1 expression is needed to extend lifespan in dilp2 mutant flies. Single dilp1 mutation has no effect on female lifespan, whereas transgene expression of dilp1 in flies with dilp1-dilp2 double mutant genetic background increased the lifespan. Furthermore, dilp1 and dilp2 interact to control circulating sugar, starvation resistance in a redundant or synergistic way.

  • 346.
    Liao, Te-Yu
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Kullander, Sven O.
    Fang, Fang
    Phylogenetic position of rasborin cyprinids and monophyly of major lineages among the Danioninae, based on morphological characters (Cypriniformes: Cyprinidae)2011In: Journal of Zoological Systematics and Evolutionary Research, ISSN 0947-5745, E-ISSN 1439-0469, Vol. 49, no 3, p. 224-232Article in journal (Refereed)
    Abstract [en]

    The cyprinid subfamily Danioninae is one of the most important fish groups due to its inclusion of the model fish, Danio rerio. Molecular investigations have shown that species traditionally placed in the Danioninae are non-monophyletic, divided into two groups corresponding to the Danioninae and Opsariichthyinae. The Danioninae are further divided into three lineages, i.e. chedrins, danionins and rasborins. However, morphological characters determining the foregoing groups are unknown. To investigate the interrelationships among major lineages within the Danioninae, a phylogenetic analysis based on 43 morphological characters from 34 taxa was conducted. Parsimony analysis recovers the Danioninae and Opsariichthyinae to be distinguished by the Y-shaped ligament, absent in the Danioninae while present in the Opsariichthyinae. The Danioninae are divided into two tribes, Danionini and Rasborini. The Rasborini, including Boraras, Brevibora, Horadandia, Kottelatia, Rasbora, Rasboroides, Rasbosoma, Trigonopoma and Trigonostigma, are diagnosed by presence of dark supra-anal pigment and subpeduncular streak as well as presence of the rasborin process on epibranchial 4. The Danionini are composed of two subtribes, Danionina and Chedrina, the Danionina including Chela, Danio, Devario, Microdevario and Microrasbora, and the Chedrina comprising Chelaethiops, Esomus, Luciosoma, Megarasbora, Mesobola, Nematabramis, Opsarius, Raiamas and Salmophasia. The Danionina are diagnosed by the unossified interhyal and presence of the danionin foramen in the horizontal limb of the cleithrum while the Chedrina are characterized by the postcleithrum absent or greatly reduced and approximately normal to abdominal ribs when present.

  • 347.
    Liao, Te-Yu
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Ünlü, Erhan
    Kullander, Sven
    Western boundary of the subfamily Danioninae in Asia (Teleostei, Cyprinidae): derived from the systematic position of Barilius mesopotamicus based on molecular and morphological data2011In: Zootaxa, ISSN 1175-5326, E-ISSN 1175-5334, no 2880, p. 31-40Article in journal (Refereed)
  • 348.
    Liljeblad, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    Phylogeny and evolution of gall wasps: (Hymenoptera: Cynipidae)2002Doctoral thesis, comprehensive summary (Other academic)
  • 349.
    Liljestrand Rönn, Johanna L.
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Hotzy, Cosima
    Do longer genital spines in male seed beetles function as better anchors during mating?2012In: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 83, no 1, p. 75-79Article in journal (Refereed)
    Abstract [en]

    In a wide variety of taxa, males are equipped with harmful structures on their genitalia such as hooks, barbs or spines. The proximate function of these structures and the evolutionary forces behind their evolution have been discussed and investigated during the last few decades. One model system in which these structures have attracted particular attention is the Callosobruchus seed beetle group. The main suggestion for the occurrence of genital spines in this group of species has been that their primary function is to act as an anchor during mating, to aid the male in staying attached to the female. This would prevent females terminating copulation prematurely, or would hinder take-overs by rival males. We used five populations of Callosobruchus seed beetles, with differing lengths of the male genital spines, to test whether longer spines provide males with an enhanced attachment during mating. This was tested both with and without male competition in the form of rival males present or not during focal copulations. We found that males from populations with longer spines did not stay in copula for longer than males from populations with shorter spines. In addition, females mating with males with longer genital spines suffered a fitness cost in terms of lower lifetime offspring production. In conclusion, we did not find any support for the hypothesis that the primary function of genital spines in seed beetles is to serve as an anchor.

  • 350.
    Lind, Johan
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution.
    Bivarg Philanthus triangulum2017In: Fauna och flora : populär tidskrift för biologi, ISSN 0014-8903, Vol. 112, no 3, p. 42-42Article in journal (Other (popular science, discussion, etc.))
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