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  • 1
    ISSN: 1432-1939
    Schlagwort(e): Key words Brood parasitism ; Clamator glandarius ; Coevolution ; Parasite counter-defences ; Pica pica
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A long-term study of the interactions between a brood parasite, the great spotted cuckoo Clamator glandarius, and its primary host the magpie Pica pica, demonstrated local changes in the distribution of both magpies and cuckoos and a rapid increase of rejection of both mimetic and non-mimetic model eggs by the host. In rich areas, magpies improved three of their defensive mechanisms: nest density and breeding synchrony increased dramatically and rejection rate of cuckoo eggs increased more slowly. A stepwise multiple regression analysis showed that parasitism rate decreased as host density increased and cuckoo density decreased. A logistic regression analysis indicated that the probability of changes in magpie nest density in the study plots was significantly affected by the density of magpie nests during the previous year (positively) and the rejection rate of mimetic model eggs (negatively). These results are consistent with a hypothesis (the intermittent arms race hypothesis) of spatially structured cyclic changes in parasitism. During periods of parasitism, host defences continuously improve, and as a consequence, the fitness gains for parasites decrease. When host defences against parasites reach a high level, dispersing parasites have a selective advantage if they are able to emigrate to areas of low resistance. Once parasites have left an area hosts will lose their defensive adaptations due to their cost in the absence of parasitism. The scene is then set for re-colonization by great spotted cuckoos.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    ISSN: 1432-1939
    Schlagwort(e): Key words Brood parasitism ; Clamator glandarius ; Egg laying ; Multiple parasitism ; Territory
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We analysed the spatial and temporal pattern of egg laying in great spotted cuckoo females using microsatellite typing to determine parentage of the eggs and nestlings found in host (magpie) nests. The results showed that there were no exclusive laying territories in the study area. Cases of multiparasitism could be due to single females laying two or more eggs in a nest, or to several females using the same nest. In the latter case multiparasitism was due to a shortage of available host nests. We argue that the need for very large laying areas and the likely small cost of sharing parental care for chicks make the costs of defending territories higher than the benefits, which has constrained the evolution of territoriality in this species.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    ISSN: 1432-0762
    Schlagwort(e): Brood parasitism ; Clamator glandarius ; Chick recognition ; Pica pica ; Supernormal stimulus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Hosts of brood parasites have evolved the ability to discriminate non-mimetic and even mimetic eggs, but not non-mimetic chicks. Here we demonstrate that the great spotted cuckoo Clamator glandarius does not provide its magpie Pica pica host with a super-normal stimulus that helps to avoid recognition, because single cuckoo chicks introduced into otherwise unparasitized magpie nests are not fed at a higher frequency than single magpie chicks introduced to parasitized magpie nests. Another series of experiments demonstrated that magpies have the ability to discriminate cuckoo chicks, mainly when these are introduced at the end of the nestling period, and especially when the cuckoo chick together with a magpie chick is presented to adult magpies outside the nest. This supports the idea that cuckoos exploit the obligatory reaction of magpies to feed all young that have been hatched in their nests and whose “signatures” they have learnt. Furthermore, the experimental cuckoo chicks in parasitized magpie nests were more likely to be accepted than they were in non-parasitized nests. This supports the hypothesis that magpies may learn to recognise their own nestlings as those present in the nest and may indicate that a comparison between cuckoo and magpie nestlings is the basis of discrimination.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Behavioral ecology and sociobiology 37 (1995), S. 243-248 
    ISSN: 1432-0762
    Schlagwort(e): Key words Brood parasitism ; Clamator glandarius ; Chick recognition ; Pica pica ; Supernormal stimulus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Hosts of brood parasites have evolved the ability to discriminate nonmimetic and even mimetic eggs, but not nonmimetic chicks. Here we demonstrate that the great spotted cuckoo Clamator glandarius does not provide its magpie Pica pica host with a supernormal stimulus that helps to avoid recognition, because single cuckoo chicks introduced into otherwise unparasitized magpie nests are not fed at a higher frequency than single magpie chicks introduced to parasitized magpie nests. Another series of experiments demonstrated that magpies have the ability to discriminate cuckoo chicks, mainly when these are introduced at the end of the nestling period, and especially when the cuckoo chick together with a magpie chick is presented to adult magpies outside the nest. This supports the idea that cuckoos exploit the obligatory reaction of magpies to feed all young that have been hatched in their nests and whose “signatures” they have learnt. Furthermore, the experimental cuckoo chicks in parasitized magpie nests were more likely to be accepted than they were in nonparasitized nests. This supports the hypothesis that magpies may learn to recognise their own nestlings as those present in the nest and may indicate that a comparison between cuckoo and magpie nestlings is the basis of discrimination.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    ISSN: 1432-0762
    Schlagwort(e): Brood parasitism ; Clamator glandarius ; Food allocation ; Pica pica ; Supernormal stimulus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Adult magpies Pica pica provide parasitic great spotted cuckoo Clamator glandarius nestlings with a diet very similar to that fed to their own chicks. In both naturally and experimentally parasitized nests, great spotted cuckoo chicks were fed at a higher rate than magpie chicks in the same nest. This preferential allocation of food by magpie parents to great spotted cuckoo chicks is consistent with the supernormal stimulus hypothesis, because this result implies that cuckoo chicks provide stronger stimuli for parental care than host chicks. Great spotted cuckoo chicks receive most of the food brought to the nest by the foster parents, because they exploit a series of stimuli which jointly (or sometimes individually) operate as a supernormal stimulus. This hypothesis predicts that if any stimulus is masked, the efficiency of the cuckoo in eliciting parental care will decrease. Here, we analyze experimentally the effects of two of these stimuli, preferential feeding of large nestlings and of nestlings with conspicuous palatal papillae. Firstly, when we experimentally introduced one medium-sized (7–9 days) cuckoo chick into an unparasitized magpie nest where the largest magpie chick was 12–15 days old, the cuckoo did not receive significantly more food than the average or the largest magpie chick. Secondly, when unparasitized nests were experimentally parasitized with a cuckoo chick that had its gape painted to mimic that of magpie chicks, the parasitic cuckoo received less food than the average magpie chick.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    ISSN: 1432-0762
    Schlagwort(e): Key words Brood parasitism ; Clamator glandarius ; Food allocation ; Pica pica ; Supernormal stimulus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Adult magpies Pica pica provide parasitic great spotted cuckoo Clamator glandarius nestlings with a diet very similar to that fed to their own chicks. In both naturally and experimentally parasitized nests, great spotted cuckoo chicks were fed at a higher rate than magpie chicks in the same nest. This preferential allocation of food by magpie parents to great spotted cuckoo chicks is consistent with the supernormal stimulus hypothesis, because this result implies that cuckoo chicks provide stronger stimuli for parental care than host chicks. Great spotted cuckoo chicks receive most of the food brought to the nest by the foster parents, because they exploit a series of stimuli which jointly (or sometimes individually) operate as a supernormal stimulus. This hypothesis predicts that if any stimulus is masked, the efficiency of the cuckoo in eliciting parental care will decrease. Here, we analyze experimentally the effects of two of these stimuli, preferential feeding of large nestlings and of nestlings with conspicuous palatal papillae. Firstly, when we experimentally introduced one medium-sized (7–9 days) cuckoo chick into an unparasitized magpie nest where the largest magpie chick was 12–15 days old, the cuckoo did not receive significantly more food than the average or the largest magpie chick. Secondly, when unparasitized nests were experimentally parasitized with a cuckoo chick that had its gape painted to mimic that of magpie chicks, the parasitic cuckoo received less food than the average magpie chick.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Publikationsdatum: 1999-08-07
    Beschreibung: There is a long-standing controversy regarding the mechanisms that generate the functional subdivisions of the cerebral neocortex. One model proposes that thalamic axonal input specifies these subdivisions; the competing model postulates that patterning mechanisms intrinsic to the dorsal telencephalon generate neocortical regions. Gbx-2 mutant mice, whose thalamic differentiation is disrupted, were investigated. Despite the lack of cortical innervation by thalamic axons, neocortical region-specific gene expression (Cadherin-6, EphA-7, Id-2, and RZR-beta) developed normally. This provides evidence that patterning mechanisms intrinsic to the neocortex specify the basic organization of its functional subdivisions.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Miyashita-Lin, E M -- Hevner, R -- Wassarman, K M -- Martinez, S -- Rubenstein, J L -- NS34661-01A1/NS/NINDS NIH HHS/ -- R01 MH49428-01/MH/NIMH NIH HHS/ -- R01 MH51561-01A1/MH/NIMH NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1999 Aug 6;285(5429):906-9.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Nina Ireland Laboratory of Developmental Neurobiology, Department of Psychiatry, School of Medicine, University of California San Francisco, San Francisco, CA 94143-0984, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/10436162" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; Axons/chemistry/*physiology ; Cadherins/genetics ; Calbindin 2 ; Carbocyanines ; DNA-Binding Proteins/genetics ; Gene Expression ; Homeodomain Proteins/genetics/physiology ; Immunohistochemistry ; In Situ Hybridization ; Inhibitor of Differentiation Proteins ; Lymphoid Enhancer-Binding Factor 1 ; Mice ; Mutation ; Neocortex/anatomy & histology/*embryology/growth & development/metabolism ; Nerve Fibers/physiology/ultrastructure ; Proteins/genetics ; Receptors, Cell Surface/genetics ; Receptors, Cytoplasmic and Nuclear/genetics ; Receptors, Melatonin ; S100 Calcium Binding Protein G/analysis ; Steroid 17-alpha-Hydroxylase/analysis ; Telencephalon/embryology/growth & development/physiology ; Thalamus/anatomy & histology/*embryology/growth & development/metabolism ; Transcription Factors/genetics
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
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    Unbekannt
    American Association for the Advancement of Science (AAAS)
    Publikationsdatum: 1999-05-08
    Beschreibung: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Martinez-Zaguilan, R -- New York, N.Y. -- Science. 1999 Apr 16;284(5413):433-4.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/10232985" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Angiostatins ; Cell Membrane/*enzymology/metabolism ; Endothelium, Vascular/cytology/*enzymology/metabolism ; Humans ; Hydrogen-Ion Concentration ; Neovascularization, Pathologic ; Peptide Fragments/*metabolism ; Plasminogen/*metabolism ; Proton Pumps ; Proton-Translocating ATPases/*metabolism ; *Vacuolar Proton-Translocating ATPases
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Publikationsdatum: 1998-02-07
    Beschreibung: Rab guanosine triphosphatases regulate vesicular transport and membrane traffic within eukaryotic cells. Here, a kinesin-like protein that interacts with guanosine triphosphate (GTP)-bound forms of Rab6 was identified. This protein, termed Rabkinesin-6, was localized to the Golgi apparatus and shown to play a role in the dynamics of this organelle. The carboxyl-terminal domain of Rabkinesin-6, which contains the Rab6-interacting domain, inhibited the effects of Rab6-GTP on intracellular transport. Thus, a molecular motor is a potential effector of a Rab protein, and coordinated action between members of these two families of proteins could control membrane dynamics and directional vesicular traffic.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Echard, A -- Jollivet, F -- Martinez, O -- Lacapere, J J -- Rousselet, A -- Janoueix-Lerosey, I -- Goud, B -- New York, N.Y. -- Science. 1998 Jan 23;279(5350):580-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Unite Mixte de Recherche CNRS 144 et 168, Institut Curie, 26 rue d'Ulm, 75248 Paris Cedex 05, France.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/9438855" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Adenosine Triphosphatases/metabolism ; Alkaline Phosphatase/metabolism ; Amino Acid Sequence ; Biological Transport ; Carrier Proteins/*metabolism ; Endoplasmic Reticulum/metabolism ; Golgi Apparatus/chemistry/*metabolism/ultrastructure ; Guanosine Triphosphate/metabolism ; HeLa Cells ; Humans ; Kinesin/analysis/chemistry/genetics/*metabolism ; Microtubules/metabolism/ultrastructure ; Molecular Sequence Data ; Molecular Weight ; *rab GTP-Binding Proteins ; ras Proteins/*metabolism
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Publikationsdatum: 1997-08-22
    Beschreibung: It has been suggested that European Middle Pleistocene humans, Neandertals, and prehistoric modern humans had a greater sexual dimorphism than modern humans. Analysis of body size variation and cranial capacity variation in the large sample from the Sima de los Huesos site in Spain showed instead that the sexual dimorphism is comparable in Middle Pleistocene and modern populations.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Arsuaga, J L -- Carretero, J M -- Lorenzo, C -- Gracia, A -- Martinez, I -- Bermudez de Castro, J M -- Carbonell, E -- New York, N.Y. -- Science. 1997 Aug 22;277(5329):1086-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Departamento de Paleontologia, Instituto de Geologia Economica, Facultad de Ciencias Geologicas, Universidad Complutense de Madrid, Ciudad Universitaria 28040 Madrid, Spain.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/9262474" target="_blank"〉PubMed〈/a〉
    Schlagwort(e): Animals ; *Body Constitution ; Female ; *Fossils ; Hominidae/*anatomy & histology ; Humans ; Male ; *Sex Characteristics ; Skull/*anatomy & histology ; Spain
    Print ISSN: 0036-8075
    Digitale ISSN: 1095-9203
    Thema: Biologie , Chemie und Pharmazie , Informatik , Medizin , Allgemeine Naturwissenschaft , Physik
    Standort Signatur Erwartet Verfügbarkeit
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