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  • 201.
    Jansson, Mija
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Ståhl, Ingvar
    Laikre, Linda
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    mPed: a computer program for converting pedigree data to a format used by the PMx-software for conservation genetic analysis2013In: Conservation Genetics Resources, ISSN 1877-7252, E-ISSN 1877-7260, Vol. 5, no 3, p. 651-653Article in journal (Refereed)
    Abstract [en]

    There is a growing need for conservation genetic management of animal populations when individual relatedness data (pedigrees) are available. Such data can be used to monitor rates of inbreeding and loss of genetic diversity. Traditionally, pedigree analysis for conservationmanagement has focused on zoo populations of threatened wild animals; available software has been developed in that context. Population Management x (PMx) is a free software for estimating genetic parameters including inbreeding, kinship, founder allele contribution and survival. PMx is an accessory program to the zoo studbook platform Single Population Analysis and Records Keeping System (SPARKS) and is not easily applied outside this platform, but such use is of interest for various domestic breeds or wild populations. We developed a converter program (mPed) for making pedigrees of any studbook format fitting the input requirements of PMx. mPed can be downloaded free at www.popgen.su.se/mped.php

  • 202.
    Janz, Niklas
    Stockholm University.
    Ecology and evolution of butterfly host plant range1999Doctoral thesis, comprehensive summary (Other academic)
  • 203.
    Janz, Niklas
    Stockholm University, Faculty of Science, Department of Zoology.
    Ehrlich and Raven Revisited: Mechanisms Underlying Codiversification of Plants and Enemies2011In: Annual Review of Ecology, Evolution and Systematics, ISSN 1543-592X, E-ISSN 1545-2069, Vol. 42, p. 71-89Article, review/survey (Refereed)
    Abstract [en]

    After almost 50 years of scrutiny, the ideas that Ehrlich and Raven presented in their classical paper on the coevolution between butterflies and plants are still very much alive. Much of this interest has involved the potential for codiversification, both in how the interaction itself diversifies and how the interaction affects modes and rates of speciation. Despite high levels of conservatism and specialization, diversification of the interaction appears to be mainly a consequence of host shifts, but this somewhat paradoxical conclusion can be understood by an appreciation of the ecological as well as genetic mechanisms behind host shifts. There are several ways that the interaction can influence speciation, with or without host-plant-based di-vergent selection on reproductive barriers. One current debate is over the relative importance of radiations following shifts to new adaptive zones and elevated rates of speciation in groups with plastic and diverse host use.

  • 204.
    Janz, Niklas
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Bergström, Anders
    Stockholm University, Faculty of Science, Department of Zoology.
    Johansson, Josefin
    Frequency dependence of host plant choice within and between patches: a large cage experiment2005In: Evolutionary Ecology, ISSN 0269-7653, E-ISSN 1573-8477, Vol. 19, no 3, p. 289-302Article in journal (Refereed)
    Abstract [en]

    Oviposition preference is considered to be one of the most important factors behind patterns of host use among herbivorous insects. However, preference is defined as host plant choice under equal host abundance and availability, and it is likely that frequency-dependent effects will alter the actual pattern of host use beyond what preference trials reveals. The effects of such alterations are poorly known but could be important for the understanding of specialization and host shifts. We investigated how changes in frequency of a preferred and a less preferred host affected movement patterns and egg deposition within and among patches in a polyphagous butterfly, Polygonia c-album. Two experiments were carried out in large (8 × 30 m) outdoor cages, artificially divided into distinct patches with different frequencies of the two hosts: one that allowed for limited movement between patches and one that did not. There was a clear effect of frequency on patch selection; females spent more time in and laid more eggs in patches with a high frequency of the preferred host, which will potentially have a large effect on host use by modifying encounter rates in favor of the preferred host. However, there was no significant frequency-dependent plant choice within patches in any experiment. Instead, results indicate that females are distributing their eggs among plants species according to specific likelihoods of oviposition, independent of encounter rates, which is compatible with a strategy of risk-spreading.

  • 205.
    Jaros, Peter P.
    et al.
    Rheinische Friedrich-Wilhelms-Universität, Germany.
    Dircksen, Heinrich
    Rheinische Friedrich-Wilhelms-Universität, Germany.
    Keller, Rainer
    Rheinische Friedrich-Wilhelms-Universität, Germany.
    Occurrence of immunoreactive enkephalins in a neurohemal organ and other nervous structures in the eyestalk of the shore crab, Carcinus maenas L. (Crustacea, Decapoda)1985In: Cell and Tissue Research, ISSN 0302-766X, E-ISSN 1432-0878, Vol. 241, no 1, p. 111-117Article in journal (Refereed)
    Abstract [en]

    Light-microscopical observations with immunofluorescence and peroxidase staining procedures revealed leu-enkephalin-like immunoreactivity in axon profiles of the sinus gland (SG) and in single small neurons in the optic ganglia of the eyestalk of Carcinus maenas. Electron microscopy of the SG showed reactivity to be associated with neurosecretory granules 82±23 nm in diameter. High performance liquid chromatography of SG-extracts revealed radioimmunoreactive substances with the retention times of synthetic met- and leu-enkephalin and met-enkephalin-Arg6-Phe7, respectively.

  • 206. Jensen, O. P.
    et al.
    Hansson, Sture
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Didrikas, T.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Stockwell, J. D.
    Hrabik, T. R.
    Axenrot, T.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Kitchell, J. F.
    Foraging, bioenergetic and predation constraints on diel vertical migration: field observations and modelling of reverse migration by young-of-the-year herring Clupea harengus2011In: Journal of Fish Biology, ISSN 0022-1112, E-ISSN 1095-8649, Vol. 78, no 2, p. 449-465Article in journal (Refereed)
    Abstract [en]

    Diel vertical migration (DVM) of young-of-the-year (YOY) herring Clupea harengus and one of their major predators, pikeperch Sander lucioperca, was examined using bottom-mounted hydroacoustics in Himmerfjarden, a brackish bay of the Baltic Sea, in summer. In contrast to previous studies on DVM of C. harengus aggregated across size and age classes, YOY C. harengus showed a reverse DVM trajectory, deeper at night and, on average, shallower during the day. This pattern was observed consistently on five acoustic sampling occasions in 3 years and was corroborated by two out of three trawl surveys. Large acoustic targets (target strength >-33 dB, probably piscivorous S. lucioperca > 45 cm) showed a classic DVM trajectory, shallow at night and deeper during the day. Variability in YOY C. harengus vertical distribution peaked at dawn and dusk, and their vertical distribution at midday was distinctly bimodal. This reverse DVM pattern was consistent with bioenergetic model predictions for YOY C. harengus which have rapid gut evacuation rates and do not feed at night. Reverse DVM also resulted in low spatial overlap with predators.

  • 207. Johanson, K.A.
    et al.
    Kjer, K
    Malm, Tobias
    Stockholm University, Faculty of Science, Department of Zoology.
    Testing the monophyly of the New Zealand and Australian endemic family Conoesucidae Ross based on combined molecular and morphological data (Insecta: Trichoptera: Sericostomatoidea)2009In: Zoologica Scripta, ISSN 0300-3256, E-ISSN 1463-6409, Vol. 38, no 6, p. 563-573Article in journal (Refereed)
    Abstract [en]

    Conoesucidae (Trichoptera, Insecta) are restricted to SE Australia, Tasmania and New Zealand. The family includes 42 described species in 12 genera, and each genus is endemic to either New Zealand or Australia. Although monophyly has been previously assumed, no morphological characters have been proposed to represent synapomorphies for the group. We collected molecular data from two mitochondrial genes (16S and cytochrome oxidase I), one nuclear gene (elongation factor 1-alpha) (2237-2277 bp in total), and 12 morphological characters to produce the first phylogeny of the family. We combined the molecular and morphological characters and performed both a maximum parsimony analysis and a Bayesian analysis to test the monophyly of the family, and to hypothesize the phylogeny among its genera. The parsimony analysis revealed a single most parsimonious tree with Conoesucidae being a monophyletic taxon and sistergroup to the Calocidae. The Bayesian inference produced a distribution of trees, the consensus of which is supported with posterior probabilities of 100% for 15 out of 22 possible ingroup clades including the most basal branch of the family, indicating strong support for a monophyletic Conoesucidae. The most parsimonious tree and the tree from the Bayesian analysis were identical except that the ingroup genus Pycnocentria changed position by jumping to a neighbouring clade. Based on the assumption that the ancestral conoesucid species was present on both New Zealand and Australia, a biogeographical analysis using the dispersal-vicariance criteria demonstrated that one or two (depending on which of the two phylogenetic reconstructions were applied) sympatric speciation events took place on New Zealand prior to a single, late dispersal from New Zealand to Australia.

  • 208.
    Johanson, Kjell Arne
    et al.
    Swedish Museum of Natural History, Department of Entomology.
    Espeland, Marianne
    Stockholm University, Faculty of Science, Department of Zoology.
    Phylogeny of the Ecnomidae (Insecta: Trichoptera)2010In: Cladistics, ISSN 0748-3007, E-ISSN 1096-0031, Vol. 26, no 1, p. 36-48Article in journal (Refereed)
    Abstract [en]

    Ecnomidae are a family of seven previously accepted extant genera having a typical Gondwanan distribution, except one genus (Ecnomus) being widely distributed also in the Oriental and Palearctic regions. We analysed a molecular data set of 3379 characters representing the sum of four different protein-coding genes (COI, CAD, EF-1a and POL-II). Six equally most parsimonious trees were generated from the combined data set, distributed into two distinct islands. In all maximum parsimony (MP) trees the Ecnomidae is monophyletic when the genus Zelandoptila (Psychomyiidae) is included. The sister group to Ecnomidae including Zelandoptila is Pseudoneureclipsis, previously classified in the other families. This sister-group relationship contradicts earlier findings that the Polycentropodidae are the sister group to Ecnomidae. A Bayesian analysis resulted in a monophyletic Ecnomidae when accepting inclusion of Pseudoneureclipsis, which contradicts the results from the MP analysis by leaving Zelandoptila as the sister group to Ecnomidae including Pseudoneureclipsis. In the majority rule tree from this analysis Polycentropodidae form the sister group to Ecnomidae. We were not able to obtain a monophyletic Ecnomus due to the inclusion of Psychomyillodes. We conclude that the genus Zelandoptila or Pseudoneureclipsis probably belongs to the Ecnomidae, and that Psychomyiellodes and Ecnomus are synonyms. Three additional, as yet undescribed monotypic genera from Australia and New Caledonia remain to be erected in Ecnomidae.

  • 209.
    Johansson, Agneta
    Stockholm University, Faculty of Science, Department of Zoology.
    Territorial dynamics and marking behaviour in male roe deer1996Doctoral thesis, comprehensive summary (Other academic)
  • 210.
    Johansson, Anna-Karin
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Sellström, Ulla
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Lindberg, Peter
    Bignert, Anders
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Environmental Chemistry.
    De Wit, Cynthia A
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Polybrominated diphenyl ether congener patterns, hexabromocyclododecane, and brominated biphenyl 153 in eggs of peregrine falcons (Falco peregrinus) breeding in Sweden.2009In: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 28, no 1, p. 9-17Article in journal (Refereed)
    Abstract [en]

    Previous analyses of 52 peregrine falcon (Falco peregrinus) eggs collected from two wild and one captive population in Sweden 1987 through 1999 were complemented by including additional polybrominated diphenyl ether (PBDE) congeners (BDE-35, -183, -184, -185, -196, -197, -203, and -207). In addition, 31 eggs not previously analyzed for hexabromocyclododecane (HBCD) and BDE-209 were analyzed for these. Geometric mean concentrations of BPBDEs, HBCD, and the hexabrominated biphenyl (BB-153) were 3,100, 140, and 81 ng/g of lipid weight for the southern population; 2,500, 110, and 84 ng/g of lipid weight for the northern population; and 47, not detected, and 8 ng/g of lipid weight for the captive population. The BDE congener pattern was dominated by BDE-153, -99, and -100. The results were used to investigate whether a difference in PBDE congener pattern could be distinguished between the two wild populations of peregrine falcons due to different diets, as the southern population preys mainly on birds belonging to the terrestrial food chain while the northern population preys more on aquatic birds. A multivariate t-test showed a subtle but significant (p < 0.001) difference in PBDE congener pattern between the two populations. However, our hypothesis that higher-brominated congeners of PBDEs would be present to a greater extent in the terrestrial food chain was not supported by principal component analysis. The average brood size for individual females from the southern population decreased with increasing concentrations of IPBDE in the eggs (log-linear regression p < 0.01).

  • 211.
    Johansson, Birgitta
    Stockholm University, Faculty of Science, Department of Zoology.
    Oxygen deficiency and the ecology of Baltic macrobenthos1997Doctoral thesis, comprehensive summary (Other academic)
  • 212.
    Johansson, Ulf. S.
    Stockholm University, Faculty of Science, Department of Zoology.
    Clades in the "higher land bird assemblage"2002Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis summarizes the results of several phylogenetic studies of birds included in the “higher land bird assemblage” (Anomalogonatae sensu Beddard 1898). The phylogenetic analyses are primarily based on gene sequences obtained from the nuclear genome (exons of the c-myc and RAG-1 genes and an intron of the myoglobin gene).  Monophyly of the “higher land bird assemblage” has previously been suggested based on the loss of the ambiens muscle in these birds. However, in agreement with other molecular studies, the results presented do not corroborate the monophyly of this group, although the tree is basically unresolved to due lack of statistical support (Bootstrap, parsimony jackknifing and Bayesian inference). Of the groups included in the “higher land bird assemblage”, Strigiformes (owls), Apodiformes (swifts and hummingbirds), Coliiformes (mousebirds), Trogoniformes (trogons), Piciformes (e.g., woodpeckers, barbets, toucans, puffbirds, jacamars) and Passeriformes (passerines) are supported as monophyletic, whereas Caprimulgiformes (e.g., nightjars, oilbird, and owletnightjars) and Coraciiformes (e.g., rollers, cuckoo-rollers, bee-eaters, kingfishers, hoopoes, hornbills) are not. Among the caprimulgiform birds, the owlet-nightjars (Aegothelidae) are found to be closer to the swifts and hummingbirds (Apodiformes) than to other caprimulgiforms.  In addition, the results indicate that the cuckoo-roller (Leptosomatidae) is not associated with rollers and ground-rollers as suggested by some previous studies. Instead, the rollers and ground-rollers (Coracioidea) are probably sister group to a clade containing todies, motmots, kingfishers, and bee-eaters (Alcedini). Hoopoes, woodhoopoes, and hornbills are monophyletic (Bucerotimorphae). As in many previous analyses, the relationships between Strigiformes, Apodiformes, Coliiformes, Trogoniformes, Piciformes, Passeriformes, Leptosomatidae, Coracioidea, Alcedini, and Bucerotimorphae are unresolved, which could indicate that these groups underwent a rapid evolution, probably in the late Cretaceous – early Tertiary.   

  • 213. Johard, Helena Anna Dagmar
    Neuropeptide signaling in insects: peptide binding sites, tachykinin receptors and SNAP-252003Doctoral thesis, comprehensive summary (Other academic)
  • 214. Johnen, Christa
    Dircksen, Heinrich
    Stockholm University, Faculty of Science, Department of Zoology, Functional Morphology.
    Changes in haemolymph ecdysteroid levels and CNS contents of crustacean cardioactive peptide-immunoreactivity during the moult cycle of the isopod Oniscus asellus1995In: Netherlands journal of zoology (Print), ISSN 0028-2960, E-ISSN 1568-542X, Vol. 45, p. 38-40Article in journal (Refereed)
    Abstract [en]

    By use of newly developed enzyme immunoassays for ecdysteroids (ECD) and crustacean cardioactive peptide (CCAP) it was found (1) that in the isopod Oniscus asellus a peak occurs of hemolymph (HL)-ECD contents in prcmoult stages followed by a second but smaller peak 1 h after posterior ecdysis, and (2) that concomitantly with a drop in the first ECD-peak, CCAP-contcnts of the ventral nerve cord rise tenfold basal level around posterior ecdysis. This suggests that CCAP plays a role in isopod moulting processes.

  • 215.
    Jorde, Per Erik
    Stockholm University, Faculty of Science, Department of Zoology, Population Genetics.
    Temporal allele frequency change in populations with overlapping generations: estimation of effective size of natural populations as exemplified using brown trout (Salmo trutta)1995Doctoral thesis, comprehensive summary (Other academic)
  • 216. Jormalainen, Veijo
    et al.
    Wikström, Sowa A.
    Stockholm University, Faculty of Science, Department of Botany.
    Honkanen, Tuija
    Fouling mediates grazing: intertwining of resistances to multiple enemies in the brown alga Fucus vesiculosus2008In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 155, no 3, p. 559-569Article in journal (Refereed)
    Abstract [en]

    Macroalgae have to cope with multiple natural enemies, such as herbivores and epibionts. As these are harmful for the host, the host is expected to show resistance to them. Evolution of resistance is complicated by the interactions among the enemies and the genetic correlations among resistances to different enemies. Here, we explored genetic variation in resistance to epibiosis and herbivory in the brown alga Fucus vesiculosus, both under conditions where the enemies coexisted and where they were isolated. F. vesiculosus showed substantial genetic variation in the resistance to both epibiosis and grazing. Grazing pressure on the alga was generally lower in the presence than in the absence of epibiota. Furthermore, epibiosis modified the susceptibility of different algal genotypes to grazing. Resistances to epibiosis and grazing were independent when measured separately for both enemies but positively correlated when both these enemies coexisted. Thus, when the enemies coexisted, the fate of genotypes with respect to these enemies was intertwined. Genotypic correlation between phlorotannins, brown-algal phenolic secondary metabolites, and the amount of epibiota was negative, indicating that these compounds contribute to resistance to epibiosis. In addition, phlorotannins correlated also with the resistance to grazing, but this correlation disappeared when grazing occurred in the absence of epibiota. This indicates that the patterns of selection for the type of the resistance as well as for the resistance traits vary with the occurrence patterns of the enemies.

  • 217.
    Kaby, Ulrika
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Lind, Johan
    Stockholm University, Faculty of Science, Department of Zoology.
    What limits predator detection in blue tits (Parus caeruleus): posture, task or orientation2003In: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 54, no 6, p. 534-538Article in journal (Refereed)
    Abstract [en]

    To detect threats and reduce predation risk prey animals need to be alert. Early predator detection and rapid anti-predatory action increase the likelihood of survival. We investigated how foraging affects predator detection and time to take-off in blue tits (Parus caeruleus) by subjecting them to a simulated raptor attack. To investigate the impact of body posture we compared birds feeding head-down with birds feeding head-up, but could not find any effect of posture on either time to detection or time to take-off. To investigate the impact of orientation we compared birds having their side towards the attacking predator with birds having their back towards it. Predator detection, but not time to take-off, was delayed when the back was oriented towards the predator. We also investigated the impact of foraging task by comparing birds that were either not foraging, foraging on chopped mealworms, or foraging on whole ones. Foraging on chopped mealworms did not delay detection compared to nonforaging showing that foraging does not always restrict vigilance. However, detection was delayed more than 150% when the birds were foraging on whole, live mealworms, which apparently demanded much attention and handling skill. Time to take-off was affected by foraging task in the same way as detection was. We show that when studying foraging and vigilance one must include the difficulty of the foraging task and prey orientation.

  • 218.
    Kahrl, Ariel F.
    et al.
    Stockholm University, Faculty of Science, Department of Zoology. University of Virginia, USA.
    Cox, Robert M.
    Consistent Differences in Sperm Morphology and Testis Size between Native and Introduced Populations of Three Anolis Lizard Species2017In: Journal of Herpetology, ISSN 0022-1511, E-ISSN 1937-2418, Vol. 51, no 4, p. 532-537Article in journal (Refereed)
    Abstract [en]

    Sperm morphology can be highly variable among individuals and across species, but less is known about its variation among populations. Within the past 20-80 yr, several species of Anolis lizards have been introduced to Miami, Florida, USA from different source islands in the Caribbean, thereby permitting comparisons of sperm morphology between native and introduced populations of multiple species. We collected sperm samples from native populations of Anolis sagrei (Bahamas), Anolis distichus (Dominican Republic), and Anolis cristatellus (Puerto Rico) and compared them to samples from introduced populations of each species that are now sympatric in Miami. In each of these three species, lizards from introduced populations had sperm with shorter tails and larger midpieces relative to lizards from native populations. We also measured testis size in A. distichus and A. cristatellus and found that introduced populations of each species had smaller testes for a given body size relative to their native counterparts. The consistency of these differences across species argues against random genetic drift as an explanation, suggesting instead that sperm morphology and testis size may exhibit predictable phenotypic plasticity or genetic adaptation in response to the process of introduction and/or the shared local environment in Florida. Though these population differences in male reproductive physiology and morphology may be repeatable, their underlying causes require further study.

  • 219.
    Kahsai, Lily
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Carlsson, Mikael A.
    Stockholm University, Faculty of Science, Department of Zoology.
    Winther, Åsa M.
    Stockholm University, Faculty of Science, Department of Zoology.
    Nässel, Dick R.
    Stockholm University, Faculty of Science, Department of Zoology.
    Distribution of metabotropic receptors of serotonin, dopamine, GABA, glutamate, and short neuropeptide F in the central complex of Drosophila2012In: Neuroscience, ISSN 0306-4522, E-ISSN 1873-7544, Vol. 208, p. 11-26Article in journal (Refereed)
    Abstract [en]

    The central complex is a prominent set of midline neuropils in the insect brain, known to be a higher locomotor control center that integrates visual inputs and modulates motor outputs. It is composed of four major neuropil structures, the ellipsoid body (EB), fan-shaped body (FB), noduli (NO), and protocerebral bridge (PB). In Drosophila different types of central complex neurons have been shown to express multiple neuropeptides and neurotransmitters; however, the distribution of corresponding receptors is not known. Here, we have mapped metabotropic, G-protein–coupled receptors (GPCRs) of several neurotransmitters to neurons of the central complex. By combining immunocytochemistry with GAL4 driven green fluorescent protein, we examined the distribution patterns of six different GPCRs: two serotonin receptor subtypes (5-HT1B and 5-HT7), a dopamine receptor (DopR), the metabotropic GABAB receptor (GABABR), the metabotropic glutamate receptor (DmGluRA) and a short neuropeptide F receptor (sNPFR1). Five of the six GPCRs were mapped to different neurons in the EB (sNPFR1 was not seen). Different layers of the FB express DopR, GABABR, DmGluRA, and sNPFR1, whereas only GABABR and DmGluRA were localized to the PB. Finally, strong expression of DopR and DmGluRA was detected in the NO. In most cases the distribution patterns of the GPCRs matched the expression of markers for their respective ligands. In some nonmatching regions it is likely that other types of dopamine and serotonin receptors or ionotropic GABA and glutamate receptors are expressed. Our data suggest that chemical signaling and signal modulation are diverse and highly complex in the different compartments and circuits of the Drosophila central complex. The information provided here, on receptor distribution, will be very useful for future analysis of functional circuits in the central complex, based on targeted interference with receptor expression.

  • 220. Kaikusalo, A.
    et al.
    Angerbjörn, Anders
    Stockholm University, Faculty of Science, Department of Zoology.
    The Arctic Fox Population in Finnish Lapland During 30 Years, 1964-931995In: Annales Zoologici Fennici, ISSN 0003-455X, E-ISSN 1797-2450, Vol. 32, no 1, p. 69-77Article in journal (Refereed)
    Abstract [en]

    We have monitored the number of arctic foxes and microtine rodents in northern Finland for 30 years. Arctic fox densities were estimated by inventories at den sites, and microtine abundance by snap trapping. Time series analyses showed that the arctic fox population fluctuated widely but always close together with the microtines in a five year cycle. However, there was no time lag in the numerical response of foxes on microtines. The strong dependence on microtines was confirmed by analyses of faecal droppings and food remains at dens. In summer time microtines consisted in average of 45% of the diet and reindeer 30%, but during winters reindeer was the most important food source with 45% compared to 15% for microtines. There was a surprising positive correlation between number of voles and reindeer carcasses, suggesting competition or alternatively an external correlation from e.g. weather. Mean litter size of the arctic fox was also highly dependent on microtine abundance but decreased during the study period despite that food resources had not changed. Further, when microtines had high densities during two consecutive years, arctic foxes only responded to the first year. A feeding experiment resulted in an increase in number of red foxes but had no or little effect on arctic foxes. So, it is difficult to single out one explanation to the decline and second year effect. Food was probably not involved and we do not know if diseases and parasites have been involved. However, both competition and predation, primarily from the red fox, may be responsible together with climatic or weather changes.

  • 221.
    Kapan, Neval
    Stockholm University, Faculty of Science, Department of Zoology.
    Peptide and GABA regulation of Peptide Hormone Release in the Drosophila Brain2010Licentiate thesis, comprehensive summary (Other academic)
  • 222.
    Karlsson, Bengt
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Extended season for northern butterflies2014In: International journal of biometeorology, ISSN 0020-7128, E-ISSN 1432-1254, Vol. 58, no 5, p. 691-701Article in journal (Refereed)
    Abstract [en]

    Butterflies are like all insects temperature sensitive and a changing climate with higher temperatures might affect their phenology. Several studies have found support for earlier flight dates among the investigated species. A comparative study including 66 species of Swedish butterflies in Sweden was undertaken and the result confirms that most butterfly species will now fly earlier during the season. This is especially evident for butterflies overwintering as adults or as pupae. However, the advancement in phenology is correlated with flight date and some late season species show no advancement or have even postponed their flight dates and are now flying later in the season. The result also showed that latitude had a strong effect on the adult flight date, and the majority of the investigated species showed significantly later flights towards the north. Species flying early in the season were more affected by temperature than species flying later in the season and species overwintering in their late stages (as pupae or adults) were more influenced by temperature compared to species overwintering in their early stages (as larvae or eggs). In essence, a climate with earlier springs and longer growing seasons seems not to change the appearance patterns in a one way direction. We now see butterflies on the wings both earlier and later in the season and some consequences of these understudied and complex patterns are discussed. So far, studies have concentrated mostly on early season butterfly – plant interactions but also late season studies are needed for a better understanding of long term population consequences.

  • 223. Karlsson, Sten
    et al.
    Hagen, Merethe
    Eriksen, Line
    Hindar, Kjetil
    Jensen, Arne J.
    de Leaniz, Carlos Garcia
    Cotter, Deirdre
    Guðbergsson, Guðni
    Kahilainen, Kimmo
    Guðjónsson, Sigurður
    Romakkaniemi, Atso
    Ryman, Nils
    Stockholm University, Faculty of Science, Department of Zoology.
    A genetic marker for the maternal identification of Atlantic salmon x brown trout hybrids2013In: Conservation Genetics Resources, ISSN 1877-7252, E-ISSN 1877-7260, Vol. 5, no 1, p. 47-49Article in journal (Refereed)
    Abstract [en]

    Interspecific hybridization between Atlantic salmon and brown trout is well documented, but why it should vary so much among populations is not clear. Determining the maternal origin of hybrids can provide insights into the mechanisms underlying interspecific hybridization, but this information is lacking in many studies. Here we present a species-specific mitochondrial DNA marker for the identification of the maternal origin of hybrids. This marker involves only one PCR step followed by fragment analysis, can be integrated within PCR multiplexing for existing nuclear markers for hybrid identification, and is therefore faster and more cost-effective than previous methods.

  • 224.
    Kautsky, Ulrik
    Stockholm University, Faculty of Science, Department of Zoology.
    Ecosystem processes in coastal areas of the Baltic sea1995Doctoral thesis, comprehensive summary (Other academic)
  • 225.
    Kazemi, Baharan
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Gamberale-Stille, Gabriella
    Stockholm University, Faculty of Science, Department of Zoology.
    Leimar, Olof
    Stockholm University, Faculty of Science, Department of Zoology.
    Multi-trait mimicry and the relative salience of individual traits2015In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 282, no 1818, article id 20152127Article in journal (Refereed)
    Abstract [en]

    Mimicry occurs when one species gains protection from predators by resembling an unprofitable model species. The degree of mimic-model similarity is variable in nature and is closely related to the number of traits that the mimic shares with its model. Here, we experimentally test the hypothesis that the relative salience of traits, as perceived by a predator, is an important determinant of the degree of mimic-model similarity required for successful mimicry. We manipulated the relative salience of the traits of a two-trait artificial model prey, and subsequently tested the survival of mimics of the different traits. The unrewarded model prey had two colour traits, black and blue, and the rewarded prey had two combinations of green, brown and grey shades. Blue tits were used as predators. We found that the birds perceived the black and blue traits similarly salient in one treatment, and mimic-model similarity in both traits was then required for high mimic success. In a second treatment, the blue trait was the most salient trait, and mimic-model similarity in this trait alone achieved high success. Our results thus support the idea that similar salience of model traits can explain the occurrence of multi-trait mimicry.

  • 226. Kelehear, Crystal
    et al.
    Webb, JK
    Hagman, Mattias
    Univ Sydney, Sch Biol Sci A08, Sydney, NSW 2006, Australia.
    Shine, Rick
    Interactions between infective helminth larvae and their anuran host2011In: Herpetologica, ISSN 0018-0831, E-ISSN 1938-5099, Vol. 67, no 4, p. 378-385Article in journal (Refereed)
    Abstract [en]

    Detailed observations on interactions between parasites and prospective hosts during the infection process can clarify (1) the routes by which parasites enter the host and (2) the ability of prospective hosts to detect, avoid, or resist potential parasites. Such information can clarify determinants of host vulnerability. Infective larvae of the nematode Rhabdias pseudosphaerocephala entered the bodies of their anuran host the Cane Toad (Rhinella marina, formerly Bufo marinus) primarily through the orbit (i.e., by crawling over the surface of the toad's eye) rather than by burrowing through the skin (believed to be the usual route of infection for rhabditid parasites). In our experimental infections, metamorph Cane Toads detected infective R. pseudosphaerocephala larvae but did not avoid them, nor did they manage to restrict rates of infective larvae penetration by using behavioral means (the toads kicked at infective larvae but failed to dislodge them). Rhabdias pseudosphaerocephala cause damage to their toad host during the process of host entry and throughout the ensuing infection. Despite the high cost of infection and the low cost of avoidance, metamorph Cane Toads seem to lack effective parasite avoidance strategies.

  • 227.
    Kempe Lagerholm, Vendela
    Stockholm University, Faculty of Science, Department of Zoology. Swedish Museum of Natural History, Department of Bioinformatics and Genetics.
    Animal movement on short and long time scales and the effect on genetic diversity in cold-adapted species2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The genetic diversity in modern species is strongly affected by contemporary gene flow between populations, which in turn is governed by individual dispersal capacities and barriers in the landscape. However, current patterns of variation have also been shaped by movement over longer time-scales, such as the successive shifts in species distributions that have occurred during past climate changes. This thesis is focused on cold-adapted species, and one parameter that has greatly influenced their current genetic diversity is how they coped with climate warming at the last glacial/interglacial transition, ca 11.7 thousand years ago. I examined this in three different small herbivore taxa; true lemmings (Lemmus), ptarmigan (Lagopus) and hares (Lepus), whose modern distributions stretch from the exposed tundra to the subarctic moorlands and taiga. In the first paper, I investigated contemporary genetic structure in the cyclic Norwegian lemming (Lemmus lemmus) and proposed that mass movements during peak years act as pulses of gene flow between mountain areas, which homogenise the gene pool over surprisingly vast geographic distances. However, when I used ancient DNA to analyse the lemmings’ ability for long-term directional movement, I found that the Ice Age populations that inhabited the former midlatitude European tundra-steppe appear to have been incapable of shifting their distribution northwards following post-glacial climate warming. Instead, the results suggest that the endemic Norwegian lemming descends from an isolated population that survived the last glacial maximum in situ in a restricted ice free refugium. In contrast to the glacial lemmings, as well the majority of previously studied mammals, the ptarmigan (L. lagopus and L. muta) and hare (L. timidus) analyses revealed a long-term genetic continuity in Europe, where the midlatitude populations were able to keep pace with the rapidly changing climate at the last glacial/interglacial transition, enabling them to shift their ranges to northern and high-alpine regions. These different outcomes might be explained by ptarmigans’ flight capability that allows a less restricted dispersal across fragmented landscapes, and that the generalist nature of mountain hares makes them less vulnerable to habitat alterations. Species distribution modelling, however, indicated that continued climate warming will make some isolated regions unsuitable in the future, thereby forcing populations to adapt the new environmental conditions in order to avoid local extinctions.

  • 228.
    Khalil, Hussein
    et al.
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Pasanen Mortensen, Marianne
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Elmhagen, Bodil
    Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    The relationship between wolverine and larger predators, lynx and wolf, in a historical ecosystem context2014In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 175, no 2, p. 625-637Article in journal (Refereed)
    Abstract [en]

    Apex predators play an important role in shaping ecosystem structure. They may suppress smaller predators (mesopredators) but also subsidize scavengers via carrion provisioning. However, the importance of these interactions can change with ecosystem context. The wolverine (Gulo gulo) is a cold-adapted carnivore and facultative scavenger. It has a circumboreal distribution, where it could be either suppressed or subsidized by larger predators. In Scandinavia, the wolverine might interact with two larger predators, wolf (Canis lupus) and lynx (Lynx lynx), but human persecution decimated the populations in the nineteenth and early twentieth century. We investigated potential relationships between wolverine and the larger predators using hunting bag statistics from 15 Norwegian and Swedish counties in 1846-1922. Our best models showed a positive association between wolverine and lynx trends, taking ecological and human factors into account. There was also a positive association between year-to-year fluctuations in wolverine and wolf in the latter part of the study period. We suggest these associations could result from positive lynx-wolverine interactions through carrion provisioning, while wolves might both suppress wolverine and provide carrion with the net effect becoming positive when wolf density drops below a threshold. Wolverines could thus benefit from lynx presence and low-to-intermediate wolf densities.

  • 229. Klepsatel, Peter
    et al.
    Nagaraj Girish, Thirnahalli
    Dircksen, Heinrich
    Stockholm University, Faculty of Science, Department of Zoology, Functional Morphology.
    Gáliková, Martina
    Stockholm University, Faculty of Science, Department of Zoology, Functional Morphology. Slovak Academy of Sciences, Slovakia.
    Reproductive fitness of Drosophila is maximised by optimal developmental temperature2019In: Journal of Experimental Biology, ISSN 0022-0949, E-ISSN 1477-9145, Vol. 222, no 10, article id 202184Article in journal (Refereed)
    Abstract [en]

    Whether the character of developmental plasticity is adaptive or non-adaptive has often been a matter of controversy. Although thermal developmental plasticity has been studied in Drosophila for several traits, it is not entirely clear how it affects reproductive fitness. We, therefore, investigated how developmental temperature affects reproductive performance (early fecundity and egg-to-adult viability) of wild-caught Drosophila melanogaster. We have tested competing hypotheses on the character of developmental thermal plasticity using a full factorial design with three developmental and adulthood temperatures within the natural thermal range of this species. To account for potential intraspecific differences, we examined flies from tropical (India) and temperate (Slovakia) climate zones. Our results show that flies from both populations raised at intermediate developmental temperature (25°C) have comparable or higher early fecundity and fertility at all tested adulthood temperatures, while lower (17°C) or higher developmental temperatures (29°C) did not entail any advantage under the tested thermal regimes. Importantly, the superior thermal performance of flies raised at 25°C is apparent even after taking two traits positively associated with reproductive output into account – body size and ovariole number. Thus, in Drosophila melanogaster, development at a given temperature does not necessarily provide any advantage at this thermal environment in terms of reproductive fitness. Our findings strongly support the optimal developmental temperature hypothesis which claims that at different thermal environments the highest fitness is achieved when an organism is raised at its optimal developmental temperature.

  • 230.
    Kodandaramaiah, Ullasa
    Stockholm University, Faculty of Science, Department of Zoology.
    Effects of Wolbachia on Butterfly Life History and Ecology2011In: Advances in Medicine and Biology. Volume 16 / [ed] Leon V. Berhardt, New York: Nova Publishers , 2011Chapter in book (Other academic)
  • 231.
    Kodandaramaiah, Ullasa
    Stockholm University, Faculty of Science, Department of Zoology.
    Tectonic calibrations in molecular dating2011In: Current Zoology, Vol. 57, no 1, p. 116-124Article in journal (Refereed)
    Abstract [en]

    Molecular dating techniques require the use of calibrations, which are usually fossil or geological vicariance-based. Fossil calibrations have been criticised because they result only in minimum age estimates. Based on a historical biogeographic perspective, I suggest that vicariance-based calibrations are more dangerous. Almost all analytical methods in historical biogeography are strongly biased towards inferring vicariance, hence vicariance identified through such methods is unreliable. Other studies, especially of groups found on Gondwanan fragments, have simply assumed vicariance. Although it was previously believed that vicariance was the predominant mode of speciation, mounting evidence now indicates that speciation by dispersal is common, dominating vicariance in several groups. Moreover, the possibility of speciation having occurred before the said geological event cannot be precluded. Thus, geological calibrations can under- or overestimate times, whereas fossil calibrations always result in minimum estimates. Another major drawback of vicariant calibrations is the problem of circular reasoning when the resulting estimates are used to infer ages of biogeographic events. I argue that fossil-based dating is a superior alternative to vicariance, primarily because the strongest assumption in the latter, that speciation was caused by the said geological process, is more often than not the most tenuous. When authors prefer to use a combination of fossil and vicariant calibrations, one suggestion is to report results both with and without inclusion of the geological constraints. Relying solely on vicariant calibrations should be strictly avoided.

  • 232.
    Kodandaramaiah, Ullasa
    Stockholm University, Faculty of Science, Department of Zoology.
    The evolutionary significance of butterfly eyespots2011In: Behavioral Ecology, ISSN 1045-2249, E-ISSN 1465-7279, Vol. 22, no 6, p. 1264-1271Article in journal (Refereed)
    Abstract [en]

    Numerous butterflies have circular patterns called eyespots on their wings. Explanations for their functional value have until recently remained hypothetical. However, several studies in the last few years have supported long-standing hypotheses, and the current paper reviews these recent advances. Large and conspicuous eyespots are thought to be effective by being intimidating to predators and thus reducing predation. This hypothesis has received strong support in different studies. It has been shown that eyespots are intimidating because of their conspicuousness, but experimental support for the idea that eyespots are effective by mimicking vertebrate eyes is at the moment lacking. Studies have also tested the deflection hypothesis, where smaller marginal eyespots are thought to deflect attacks away from the body of the prey, increasing chances of survival with a torn wing. Despite previous negative results, recent work has shown that eyespots can indeed deflect attacks toward themselves under specific conditions. Furthermore, data show that dorsal eyespots are used by males and females as signals during courtship. How the diversity in ventral eyespot patterning has evolved remains a mystery. Future directions and further challenges in understanding the adaptive value of eyespots are discussed.

  • 233.
    Kodandaramaiah, Ullasa
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Weingartner, Elisabet
    Stockholm University, Faculty of Science, Department of Zoology.
    Janz, Niklas
    Stockholm University, Faculty of Science, Department of Zoology.
    Leski, Michael
    Slove, Jessica
    Stockholm University, Faculty of Science, Department of Zoology.
    Warren, Andrew
    McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida.
    Validity of the subspecies paradigm - a case study of the nymphalid butterfly Polygonia faunusIn: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203Article in journal (Refereed)
    Abstract [en]

    Subspecies are commonly used taxonomic units to formally describe intraspecific geographic variation in morphological traits. However, the concept of subspecies is not clearly defined, and there is little agreement about what they represent in terms of evolutionary units, and whether they can be used as reliably useful units in conservation, evolutionary theory and taxonomy. Although the validity of subspecies has been tested using a multi-marker genetic approach in vertebrates, such studies have been rare in invertebrates. We here test the validity of well-characterized subspecies in the butterfly Polygonia faunus using a combination of mitochondrial sequences and eight microsatellites. We have also investigated the phylogeographic Structure of P. faunus and test whether similarities in host-plant use among populations is related to genetic similarity. Neither the nuclear nor the mitochondrial dataset corroborated subspecies groupings. We found three welldefined genetic clusters corresponding to California, Arizona and (New Mexico + Colorado). There was little structuring among the remaining populations, probably due to gene flow across populations. We found no support for the hypothesis that similarities in host use are related to genetic proximity. The results indicate that the species underwent a recent rapid expansion, probably from two glacial refugia in western North America. The mitochondrial haplotype network indicates at least two independent expansion phases into eastern North America. Ourresults clearly demonstrate that subspecies in P. faunus do not conform to the structuring of genetic variation. More studies on insects and other invertebrates are needed to understand how widespread this phenomenon is. Results in this study will be crucial in designing further experiments to understand the evolution of host plant utilization in this species.

  • 234.
    Kodandaramaiah, Ullasa
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Weingartner, Elisabet
    Stockholm University, Faculty of Science, Department of Botany.
    Janz, Niklas
    Stockholm University, Faculty of Science, Department of Zoology.
    Leski, Michael
    Slove, Jessica
    Stockholm University, Faculty of Science, Department of Zoology.
    Warren, Andrew
    Nylin, Sören
    Stockholm University, Faculty of Science, Department of Zoology.
    Investigating concordance among genetic data, subspecies circumscriptions and hostplant use in the nymphalid butterfly polygonia faunus2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 7, p. e41058-Article in journal (Refereed)
    Abstract [en]

    Subspecies are commonly used taxonomic units to formally describe intraspecific geographic variation in morphological traits. However, the concept of subspecies is not clearly defined, and there is little agreement about what they represent in terms of evolutionary units, and whether they can be used as reliably useful units in conservation, evolutionary theory and taxonomy. We here investigate whether the morphologically well-characterized subspecies in the North American butterfly Polygonia faunus are supported by genetic data from mitochondrial sequences and eight microsatellite loci. We also investigate the phylogeographic structure of P. faunus and test whether similarities in host-plant use among populations are related to genetic similarity. Neither the nuclear nor the mitochondrial data corroborated subspecies groupings. We found three well defined genetic clusters corresponding to California, Arizona and (New Mexico+Colorado). There was little structuring among the remaining populations, probably due to gene flow across populations. We found no support for the hypothesis that similarities in host use are related to genetic proximity. The results indicate that the species underwent a recent rapid expansion, probably from two glacial refugia in western North America. The mitochondrial haplotype network indicates at least two independent expansion phases into eastern North America. Our results clearly demonstrate that subspecies in P. faunus do not conform to the structuring of genetic variation. More studies on insects and other invertebrates are needed to better understand the scope of this phenomenon. The results of this study will be crucial in designing further experiments to understand the evolution of hostplant utilization in this species.

  • 235.
    Koivisto, Ari
    Stockholm University, Faculty of Science.
    Nonselective cation channels in brown fat cells: adrenergic and NO regulation1997Doctoral thesis, comprehensive summary (Other academic)
  • 236.
    Koivisto, Sanna
    Stockholm University, Faculty of Science.
    Toxicity testing from an ecological perspective: life history and food web studies with cladocerans1996Doctoral thesis, comprehensive summary (Other academic)
  • 237.
    Kolodziejczyk, Agata
    Stockholm University, Faculty of Science, Department of Zoology.
    Chemical circuitry in the visual system of the fruitfly, Drosophila melanogaster2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Signal processing in the visual system is mediated by classic neurotransmission and neuropeptidergic modulatory pathways. In Dipteran insects, especially in the fruitfly Drosophila melanogaster, the morphology of the visual system is very well described. However neurotransmitter and neuropeptidergic circuits within the optic lobe neuropil are only partially known.

    Using several transgenic fly lines and antibodies we determined the localization of the classical neurotransmitters GABA, acetylcholine and glutamate in the visual system, and their putative targets via detecting several neurotransmitter receptors. We paid particular attention to the peripheral neuropil layer called the lamina, where the light signals are filtered, channeled and amplified (Paper I).

    We discovered four new types of efferent tangential neurons branching distally to the lamina. Among them was the first neuropeptidergic neuron (LMIo) in this region of Drosophila. The LMIo expresses myoinhibitory peptide (MIP) and has its cell body located close to the main lateral clock neurons that express the neuropeptide pigment-dispersing factor (PDF)(Paper II).

    Since in other Dipteran species PDF is expressed in processes distally to the lamina, we performed comparative anatomical studies of the MIP, PDF, Ion Transport Peptide (ITP) and serotonin (5-HT) distribution in the visual system of the flies Drosophila and Calliphora. Our data suggest that PDF signaling distal to the lamina of the blowfly might be replaced by MIP signaling in the fruitfly, while ITP and 5-HT expression is conserved in the two species (Paper III).

    Serotonin is crucial in light adaptation during the daily light-dark cycles. We analyzed putative serotonergic circuits in the lamina. We found that LMIo neurons express the inhibitory receptor 5-HT1A, while 5-HT1B and 5-HT2 are both expressed in the epithelial glia of the lamina. Another novel wide-field neuron with lamina branches expresses the excitatory serotonin receptor 5-HT7. Our studies have identified a fairly complex neuronal circuitry in the tangential plexus above the lamina. (Paper IV).

    Finally we tested circadian locomotor activity rhythms in flies with the GABAB receptor knocked down on the lateral PDF-expressing clock neurons. We observed significant changes in the activity periods and diminished strength of rhythmicity during DD suggesting a modulatory role of GABA in clock function (Paper V).

  • 238.
    Kolodziejczyk, Agata
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Nichols, Charles
    Nässel, Dick
    Stockholm University, Faculty of Science, Department of Zoology.
    Distribution of serotonin receptors in the visual system of the DrosophilaManuscript (preprint) (Other academic)
  • 239.
    Kolodziejczyk, Agata
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Nässel, Dick R.
    Stockholm University, Faculty of Science, Department of Zoology.
    A novel wide-field neuron with branches in the lamina of the Drosophila visual system expresses myoinhibitory peptide and may be associated with the clock2011In: Cell and Tissue Research, ISSN 0302-766X, E-ISSN 1432-0878, Vol. 343, no 2, p. 357-369Article in journal (Refereed)
    Abstract [en]

    Although neuropeptides are widespread throughout the central nervous system of the fruifly Drosophila, no records exist of peptidergic neurons in the first synaptic region of the visual system, the lamina. Here, we describe a novel type of neuron that has wide-field tangential arborizations just distal to the lamina neuropil and that expresses myoinhibitory peptide (MIP). The cell bodies of these neurons, designated lateral MIP-immunoreactive optic lobe (LMIo) neurons, lie anteriorly at the base of the medulla of the optic lobe. The LMIo neurons also arborize in several layers of the medulla and in the dorso-lateral and lateral protocerebrum. Since the LMIo resemble LN(v) clock neurons, we have investigated the relationships between these two sets of neurons by combining MIP-immunolabeling with markers for two of the clock genes, viz., Cryptochrome and Timeless, or with antisera to two peptides expressed in clock neurons, viz., pigment-dispersing factor and ion transport peptide. LMIo neurons do not co-express any of these clock neuron markers. However, branches of LMIo and clock neurons overlap in several regions. Furthermore, the varicose lamina branches of LMIo neurons superimpose those of two large bilateral serotonergic neurons. The close apposition of the terminations of MIP- and serotonin-producing neurons distal to the lamina suggests that they have the same peripheral targets. Our data indicate that the LMIo neurons are not bona fide clock neurons, but they may be associated with the clock system and regulate signaling peripherally in the visual system.

  • 240.
    Kolodziejczyk, Agata
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Nässel, Dick R.
    Stockholm University, Faculty of Science, Department of Zoology.
    Myoinhibitory peptide (MIP) immunoreactivity in the visual system of the blowfly Calliphora vomitoria in relation to putative clock neurons and serotonergic neurons2011In: Cell and Tissue Research, ISSN 0302-766X, E-ISSN 1432-0878, Vol. 345, no 1, p. 125-135Article in journal (Refereed)
    Abstract [en]

    A few types of peptidergic clock neurons have been identified in the fruitfly Drosophila, whereas in blowflies, only pigment-dispersing factor (PDF)-immunoreactive lateral ventral clock neurons (LNvs) have been described. In blowflies, but not Drosophila, a subset of these PDF-expressing neurons supplies axon branches to a region outside the synaptic layer of the lamina, the most peripheral optic lobe neuropil. In Drosophila, similar lamina processes are instead supplied by non-clock neurons (LMIo) that express myoinhibitory peptide (MIP). We have investigated the distribution of MIP-immunoreactive neurons in the visual system of the blowfly Calliphora vomitoria and found neurons resembling the three LMIos, but without processes to the lamina. In Calliphora, PDF-immunoreactive processes of LNvs in the lamina closely impinge on branching serotonin-immunoreactive axon terminations in the same region. We have also identified, in the blowfly, two types of putative clock neurons that label with an antiserum to ion-transport peptide (ITP). The presence of serotonin-immunoreactive neurons supplying processes to the lamina seems to be a conserved feature in dipteran flies. The morphology of the two types of ITP-immunoreactive clock neurons might also be conserved. However, peptidergic neurons with branches converging on the serotonin-immunoreactive neurons in the lamina are of different morphological types and express PDF in blowflies and MIP in Drosophila. The central circuitry of these PDF- and MIP-expressing neurons probably differs; consequently, whether their convergence on serotonergic neurons subserves similar functions in the two species is unclear.

  • 241.
    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)
  • 242.
    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.

  • 243.
    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.

  • 244.
    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.

  • 245.
    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.

  • 246.
    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.

  • 247.
    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.

  • 248.
    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.

  • 249.
    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.
  • 250.
    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

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