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61.
ABSTRACT Distress calls are signals effective over a long distance. They are well known to evoke interspecific reactions. We suggest that the interspecificity phenomenon results from the use of similar laws of decoding by the species concerned. These laws must take into account the transmission channel which always has a great influence on long-range communication. We tested our hypothesis by broadcasting simplified synthetic calls to two species of birds: the herring gull and the starling. The various calls differed in terms of frequency modulation (FM). Two main conclusions emerged from this series of tests: 1. The parameters used for recognition are not sophisticated: a simple slope applied to a carrier frequency that corresponds to the acoustic shape of a distress call is sufficient to confer a distress meaning to the signal. The basic rules are the same for the gull and the starling, with differences only in the acceptance level of the species. 2. The system of recognition is based upon parameters not altered by the environment: the birds make use of the slow frequency modulations (FMI). In contrast, the fast frequency sweeps (FMII) which are modified during propagation do not seem to be utilised. The use of these characteristics of distress calls for recognition allows interspecificity and maximum efficiency for propagation over long distances.
RESUME
Une particularité des cris de détresse est leur action interspécifique. Nous suggérons que cette interspécificité résulte de l'emploi d'une loi de décodage qui est commune à plusieures espèces. Cette loi doit tenir compte des propriétés du canal car ce dernier a toujours une grande influence sur les signaux de longue portée acoustique, tels que les cris de détresse. Pour tester cette hypothèse, nous avons fait appel à deux espèces: le Goéland argenté (Larus argentatus) et l'Etourneau (Sturnus vulgaris). Les signaux que nous avons diffusés étaient obtenus par synthèse. Ils étaient plus simples que les signaux naturels et différaient par la modulation de fréquence (FM). Deux résultats principaux émergent de ces séries d'expériences: 1. Le procédé de décodage n'est pas sophistiqué: une simple pente appliquée à la porteuse est nécessaire et il suffit de mimer, meme approximativement, la pente rencontrée dans les signaux naturels, Cette règle fondamentale est commune au Goéland et à l'Etourneau. Les petites différences que l'on peut néanmoins observer sont relatives aux seuils de décodage. 2. Le décodage repose sur des paramètres qui ne sont pas altérés par le canal: l'oiseau utilise la modulation lente de fréquence. Par contre les excursions rapides de fréquence semblent n'étre d'aucune utilité lors du décodage. En conclusion, l'universalité des paramètres impliqués et de la loi de décodage est responsable de l'interspécificité des signaux de détresse. Les simplifications liées à cette universalité résultent des contraintes imposées par le canal. 相似文献
62.
63.
DNA staining with Hoechst 33258 allows us to visualize and to characterize amitotic division of Acanthamoeba castellanii in which the cell nucleus divides without DNA condensation and regular segregation of chromosomes. Amitosis involves several programmed and coordinated steps that exclude accidental cutting of the cell nucleus. 相似文献
64.
CLAUDINE MONTGELARD † YVES BENYAMIN† ‡ CLAUDE ROUSTAN‡ LOUIS THALER 《Biological journal of the Linnean Society. Linnean Society of London》1990,41(1-3):163-169
An immunological test that can be made on living animals is developed to identify M. m. musculus mice from the two other short-tailed mice ( M. spicilegus and M. spretoides ) occurring in Eastern Europe. This test uses fractionated albumin antiserum as an immunological marker and is performed using dot-blot immunoassay. One hundred and twelve animals belonging to the three species and originating from wild-caught mice and from laboratory strains were tested. All the M. m. musculus mice were correctly identified with this test. Owing to its simplicity and reliability, this test will be very useful in field surveys, particularly in the zone of sympatry between M. m. musculus and M. spicilegus . 相似文献
65.
TROY SORENSEN PHILIP D. MCLOUGHLIN DAVE HERVIEUX ELSTON DZUS JACK NOLAN BOB WYNES STAN BOUTIN 《The Journal of wildlife management》2008,72(4):900-905
Abstract: Direct and indirect effects of industrial development have contributed, in part, to the threatened status of boreal ecotype caribou (Rangifer tarandus caribou) in Alberta and Canada. Our goal was to develop a model that would allow managers to identify landscape-scale targets for industrial development, while ensuring functional habitat for sustainable caribou populations. We examined the relationship between functional habitat loss resulting from cumulative effects of natural and anthropogenic disturbance, and the rate of population change (Λ) for 6 populations of boreal caribou in Alberta, Canada. We defined functional habitat loss according to 2 variables for which we had a priori reasons to suspect causative associations with Λ: 1) percentage area of caribou range within 250 m of anthropogenic footprint, and 2) percentage of caribou range disturbed by wildfire within the last 50 years. Multiple regression coefficients for both independent variables indicated significant effects on Λ. The 2-predictor model explained 96% (R2) of observed variation in Λ among population units (F2,3 = 35.2, P = 0.008). The model may be used to evaluate plans for industrial development in relation to predicted wildfire rates and goals for caribou population growth rates. 相似文献
66.
GUOQING DING GABRIELLE MAUME MARIE-LOUISE MILAT CLAUDE HUMBERT JEAN-PIERRE BLEIN BERNARD F. MAUME 《Cell biology international》1996,20(8):523-530
The proliferation of GM16 and 4CDTras-transformed newborn rat adrenocortical (RTAC) cells and Y1 mouse adrenal tumor cells was inhibited by beticolins, the fungal toxins extracted fromCercospora beticola, at submicromolar concentrations in a dose-dependent manner. Inhibitory concentrations for half the maximum inhibition were 150, 75 and 25 nm for beticolin-1 and 230, 150 and 50 nm for beticolin-2 in GM16, 4CDT and Y1 cells respectively. Beticolins strongly inhibited the production of 11β-hydroxysteroids on the second and third days of treatment in a dose-dependent manner between 0.1 and 1 μm . Beticolins were shown by confocal microscopy to be localized in cytoplasmic organelles about 30–40 min after treatment. This finding favors a direct action of beticolins on mitochondrial steroid 11β-hydroxylase albeit another less direct mechanism involving a cytoplasmic signaling pathway cannot be excluded. 相似文献
67.
PATRICK ZABORSKI MIREILLE DORIZZI CLAUDE PIEAU 《Differentiation; research in biological diversity》1982,22(1-3):73-78
H-Y antigen has been used as a marker for the heterogametic sex and is assumed to be an organizing factor for the heterogametic gonad. In the turtle Emys orbicularis , H-Y antigen is restricted to the female cells, indicating a female heterogamety (ZZ/ZW) sex-determining mechanism. Moreover, the sexual differentiation of the gonads is temperature sensitive, and complete sex reversal can be obtained at will. In this framework the relationships between H-Y antigen, temperature, and gonadal phenotype were studied. Mouse H-Y antiserum was absorbed with blood and gonadal cells of control wild male and female adults, and with blood and gonadal cells from three lots of young turtles from eggs incubated at 25–26°C (100% phenotypic males), at 30–30.5°C (100% phenotypic females), or at 28.5–29°C (majority of females with some males and intersexes). The residual activity of H-Y antiserum was then estimated using an immunobacterial rosette technique. In adults, both blood cells and gonadal cells were typed as H-Y negative in males and as H-Y positive in females. In each of the three lots of young, blood cells were H-Y negative in some individuals and H-Y positive in others. The proposed interpretation is that the H-Y negative individuals were genotypic males (ZZ) and the H-Y positive were genotypic females (ZW). The gonads of these animals were then pooled in different sets according to their sexual phenotype and to the presumed genotypic sex (i.e., blood H-Y phenotype). Testicular cells were typed as H-Y negative in genotypic males as well as in the presumed sex-reversed genotypic females; likewise, ovarian cells were typed as H-Y positive in genotypic females as well as in the presumed sex-reversed genotypic males. These results provide additional evidence that H-Y antigen expression is closely associated with ovarian structure in vertebrates displaying a ZZ/ZW sex-determining mechanism. 相似文献
68.
JEAN‐CLAUDE WALSER MICHAEL B. EVGENEV MARTIN E. FEDER 《Molecular ecology resources》2006,6(2):563-567
We adapted a recently developed nonrestrictional, nonligational genome walking method, Universal Fast Walking (UFW), for detection of length polymorphism in the proximal promoter region of genes. We demonstrate its efficacy at discovering naturally occurring transposition into heat‐shock genes of wild Drosophila and show that it surmounts limitations of simple polymerase chain reaction (PCR) approaches. We further present modifications to the standard UFW protocol and provide some guidelines to improve specificity. Although the resultant banding pattern of a standard UFW can be regarded as a DNA fingerprint, many amplicons result from false priming and not real polymorphisms. We describe ways to distinguish between UFW amplicons and false priming products in a high‐throughput assay. 相似文献
69.
Differential Staining Patterns of Heterochromatin in Man 总被引:1,自引:0,他引:1
QUINACRINE staining1 can be used to distinguish between different heterochromatic segments in various organisms and Giemsa staining has been used to locate constitutive heterochromatin in human chromosomes2. In using both these techniques on human chromosome preparations we have found certain specific staining properties of hetero-chromatic segments which suggest the existence of at least two different constitutive heterochromatins. 相似文献
70.
Helical replicative forms, but not the persistent non-replicative forms, of Spiroplasma taiwanense Abalain-Colloc et al. (isolated from the mosquito Anopheles sinensis Wiedemann in Taiwan) were shown to reduce significantly the survival of Aedes aegypti (L.) mosquito larvae reared in 10 ml of water with 0.3 ml of S.taiwanense suspensions added on days 0 and 3. The suspensions contained, respectively, helical forms at a concentration of 10(9) Colour Change Units (CCU)/ml and persistent forms at 10(6) CCU/ml. It is suggested that S.taiwanense, or toxins produced from it, are potentially useful for use in integrated mosquito control programmes. 相似文献