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  • Springer  (298)
  • 2000-2004  (76)
  • 1975-1979  (109)
  • 1970-1974  (85)
  • 1965-1969  (28)
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  • 1
    Electronic Resource
    Electronic Resource
    Interdemic variation in mixed-species association patterns: common diurnal primates of Kibale National Park, Uganda (2000)
    Springer
    Behavioral ecology and sociobiology 47 (2000), S. 129-139 
    Details
    ISSN: 1432-0762
    Keywords: Key words Polyspecific associations ; Group living ; Ecological constraints model ; Food availability ; Group size ; Social organization ; Cercopithecines ; Colobines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We used interdemic variation in the tendency to form mixed-species groups to examine the costs and benefits of association among the primates of Kibale National Park, Uganda. A year-long survey of six sites revealed that the amount of time that the five common diurnal primates [red colobus (Procolobus tephrosceles), black-and-white colobus (Colobus guereza), redtail monkeys (Cercopithecus ascanius), blue monkeys (Cercopithecus mitis), and grey-cheeked mangabeys (Lophocebus albigena)] spent in mixed-species groups varied dramatically among sites. In many cases, the proportion of time that species associated was positively related to their densities. By using detailed behavioral observations of redtail monkeys and red colobus made over 4 years (2660 h) at four sites, we were able to reject the null hypothesis that associations occur by chance for only one of four sites. However, a correlative approach exploring the costs and benefits of association suggests that ecological variables do influence association patterns. We found that redtail monkeys and red colobus overlapped in diet (19.2% of their foraging effort) and traveled further when in mixed-species groups than when alone. Having demonstrated this, we examined the applicability of the ecological constraints model for predicting the proportion of the time spent in mixed-species groups based on food availability. For this analysis we concentrated on red colobus from the site with 35 months of observation and demonstrated that their tendency to be in mixed- species groups was related to food availability. We used two methods to examine if mixed-species associations function to decrease predation risk. First, chimpanzees are known to prey heavily on red colobus, but rarely kill other primates. The time red colobus spent in mixed-species groups was correlated to chimpanzee density, but it was not for the other monkey species, suggesting that mixed-species groups serve to decrease predation risk. Second, when red colobus groups contain more infants and are presumably at the greatest risk of predation, they form mixed-species groups most often. These results demonstrate that the costs and benefits of mixed-species associations vary dramatically over small spatial and temporal scales. If such variation is generally the case, then studies conducted at different locations or different times could easily highlight the importance of difference selective agents in favoring mixed-species associations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002650050003
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  • 2
    Electronic Resource
    Electronic Resource
    Constraints on Group Size in Red Colobus and Red-tailed Guenons: Examining the Generality of the Ecological Constraints Model (2000)
    Springer
    International journal of primatology 21 (2000), S. 565-585 
    Details
    ISSN: 1573-8604
    Keywords: colobus ; cercopithecine ; group size ; social organization ; food abundance ; day range ; diet ; group movement ; ecological constraints model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The ecological constraints model proposes that an increase in group size will increase intragroup feeding competition and thereby constrain group size. Although this model has received wide acceptance, tests of it are based only on a few studies of species that have similar ecological requirements and social organizations, and there are reasons to question the widespread acceptance of the assumptions underpinning it. Via a 2-year study, we explored determinants of group size in species that feed on markedly different types of foods: the folivorous red colobus (Procolobus pennantii) and the frugivorous/insectivorous red-tailed guenon (Cercopithecus ascanius). We established 4 study sites approximately 15 km apart in Kibale National Park, Uganda, to examine the relationship between average group size and food availability. In both species, we quantified interdemic variation in diet, density of food trees, rate of travel, and group size. Red colobus at all sites relied heavily on leaf resources (75.5%–86.9%), but fruit (6.4%–13.9%) and flowers (2.0%–13.9%) were important in some populations. In general, red-tailed guenons fed on fruit (35.7%–59.7%), insects (14.5%–17.6%), and young leaves (12.2%–32.8%), but the amount of time allocated to these foods varied among sites. Average monthly density of trees bearing food items ranged among sites from 45 to 79 trees/ha for red colobus and from 19.6 to 67.3 trees/ha for red-tailed guenons. For both species, rate of travel was similar among sites, with one exception for red colobus. Average red colobus group size varied among sites from 14 to 40 (28 groups counted). Red-tailed guenon group size varied among sites from 11 to 24 (16 groups counted). As predicted by the ecological constraints model, group size increased with food tree density across sites for both species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005557002854
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  • 3
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    Unknown
    Unfavorable successional pathways and the conservation value of logged tropical forest (2004)
    Springer
    Details
    Publication Date: 2004-10-01
    Print ISSN: 0960-3115
    Electronic ISSN: 1572-9710
    Topics: Biology
    Published by Springer
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    PAPER CURRENT
  • 4
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    Unknown
    Abstracts (1977)
    Springer
    Details
    Publication Date: 1977-01-01
    Print ISSN: 0364-152X
    Electronic ISSN: 1432-1009
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering
    Published by Springer
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    PAPER CURRENT
  • 5
    Electronic Resource
    Electronic Resource
    Field studies of hearing in teleost fish (1973)
    Springer
    Helgoland marine research 24 (1973), S. 371-390 
    Details
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary 1. Field measurements of hearing in haddock,Melanogrammus aeglefinus, pollack,Pollachius pollachius and ling,Molva molva, show that they are sensitive to sounds in the frequency range from 30 to 500 Hz, with greatest sensitivity from 100 to 300 Hz. 2. At the most sensitive frequencies the thresholds varied between — 15 to — 25 dB relative to a sound pressure of 1µbar. 3. In all three species, the thresholds at some frequencies were affected by the level of ambient sea noise. A direct correlation between the thresholds and the spectrum level of sea noise was obtained in haddock and pollack. 4. The masking effect of sea noise was confirmed in some experiments on cod,Gadus morbua and haddock, where the background noise level was raised artificially. It was found that the masking of a tone signal was reduced by about 8 dB when the tone and noise were from different directions (85° apart), suggesting that directional discrimination may be well developed in these fish.
    Notes: Kurzfassung Versuche über das Hörvermögen verschiedener mariner Fische — des Schellfischs(Melanogrammus aeglefinus), des Pollacks(Pollachius pollachius), des Kabeljaus(Gadus morhua) und des Lengs(Molva molva) — wurden im Biotop, und zwar in 20 m Tiefe bei Loch Torridon (Schottland) durchgeführt. Die Reaktionen der Fische wurden mit Hilfe einer besonderen Dressurtechnik getestet, wobei dem Tonreiz ein leichter elektrischer Schock folgte; wurde das akustische Signal wahrgenommen, traten Veränderungen im Elektrokardiogramm der Fische auf. Alle 4 Arten wiesen ein ähnliches Hörvermögen auf. Im Niederfrequenzbereich von etwa 60–300 Hz wurde die höchste Empfindlichkeit registriert. Bei höheren Frequenzen stellte sich eine Verminderung der Empfindlichkeit ein; nurMolva molva konnte zuverlässig auf einen Ton von 550 Hz abgerichtet werden. Im Bereich niederer Frequenzen waren alle Fische äußerst empfindlich; es ergaben sich Hinweise, daß die Hörschwellen vom Eigenrauschen des Meeres maskiert wurden. Dies wurde durch Versuche bestätigt, bei denen die Intensität des Eigenrauschens vergrößert wurde, die Mithörschwellen aber in konstantem Abstand zum Störpegel blieben. Ferner wurde festgestellt, daß die Verdeckung reiner Töne wesentlich vermindert wurde, wenn Ton und Störpegel aus verschiedenen Richtungen (im rechten Winkel zueinander) abgestrahlt wurden. Daraus ist zu schließen, daß die Fähigkeit, die Richtung der Schallquellen zu unterscheiden, gut entwickelt sein dürfte.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01609527
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  • 6
    Electronic Resource
    Electronic Resource
    Microanatomy of the cubopolyp,Tripedalia cystophora (Class Cubozoa) (1978)
    Springer
    Helgoland marine research 31 (1978), S. 128-168 
    Details
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The microanatomy of a cubopolyp (polypoid stage of Cubomedusae) is described for the first time. The 0.5–1.0 mm long polyp ofTripedialia cystophora has an oral cone with special lip cells at the mouth. Next is a baggy calyx occasionally followed by a slender stalk. The basal region is surrounded by a thin periderm. A single row of tentacles is at the oral cone/calyx junction. The mesoglea is thin and non-cellular. The muscular system of the ectoderm is composed of smooth longitudinal epitheliomuscular cells in the oral cone, tentacle, stalk and calyx. The calyx ectoderm also sends longitudinal muscle fibers into the mesoglea. The mesogleal muscle fibers seem to contain paramyosin and perhaps are doubly innervated: one set of neurites for contraction and one for relaxation. A circular endodermal system of filaments, probably actin, is found in all regions. The tentacles have a solid core of a single row of endodermal cells capable of phagocytosis. The ectodermal tip is swollen with longitudinally aligned nematocysts. The distal part of the tentacle contains striated ectodermal myofibers. The nervous system is unique in having an endodermal/ectodermal nerve ring pair at the calyx/oral cone junction. Ganglion cells are not apparent. Presumed sense cells have complicated microvilli and no flagellar rootlet. A cell fitting the description of a neurosecretory neurone is especially prominent in the oral cone's endoderm. It has a major process reaching the coelenteron. Round macrogranular cells corresponding to the amoebocytes of the Scyphozoa and Anthozoa are found. There are no interstitial cells. The oral cone's flagellated endoderm is made up of mucous cells, cells with small dark granules, cells with large granules and rodlets in the cytoplasm, and a few absorptive cells. The calyx endoderm is very thick (120 μm) and is made up of flagellated absorptive, mucous and granular cells. Ingested food is transformed into basal droplets. 4 size and shape types of the microbasic eurytele category make up the cnidome. The largest nematocyst types are found at the tentacle's tip. Like a hydropolyp, the cubopolyp lacks gastral septa and is in other features radially symmetrical. Like a scyphopolyp, the cubopolyp has mesogleal muscles and no interstitial cells. Unique histological features are the nerve rings and tentacular striated muscles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02296994
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of parasitism on a nucleopolyhedrovirus amplified in Spodoptera frugiperda larvae parasitized by Campoletis sonorensis (2000)
    Springer
    Entomologia experimentalis et applicata 97 (2000), S. 257-264 
    Details
    ISSN: 1570-7458
    Keywords: fall armyworm ; baculovirus ; serial passage ; virulence ; genotypic variants ; per capita virus production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We evaluated the consequences of parasitism by the solitary ichneumonid endoparasitoid Campoletis sonorensis(Cameron) towards the replication, genetic composition and virulence of a nucleopolyhedrovirus (Baculoviridae) originating from Spodoptera frugiperda(J. E. Smith) larvae. Parasitism by C. sonorensisand viral infection of third and fourth instar S. frugiperdalarvae resulted in reduced growth compared with nonparasitized control larvae. A positive correlation was observed between virus yield and larval instar at the moment of infection. When larvae were virus-inoculated in the fourth instar, parasitism resulted in a significant reduction in mean per capita virus yield compared to the virus yield from nonparasitized larvae. In an experiment involving 10 serial passages of virus in both parasitized and nonparasitized larvae, restriction endonuclease analysis of viral DNA amplified in nonparasitized larvae revealed the presence of the wild-type virus as well as three additional variants (A, B, and C) diagnosed by the presence of novel submolar PstI fragments of different sizes. In contrast, analysis of viral DNA from parasitized larvae showed the presence of the wild-type virus and two other variants (E and F), each characterized by a different submolar BglII fragment. Southern blot analysis indicated that the submolar fragments of variants E and F contained sequences originating from the viral genome. Bioassay of the different virus variants in S. frugiperdalarvae indicated that their virulence was equal or less than that of the wild-type virus. We conclude that parasitism can affect the quantity of virus produced in dually infected and parasitized larvae, but no adverse effects were detected in terms of the biological activity of the virus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004071811224
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  • 8
    Electronic Resource
    Electronic Resource
    Evaluating fire prevention effectiveness through a probability model (1979)
    Springer
    Fire technology 15 (1979), S. 291-306 
    Details
    ISSN: 1572-8099
    Source: Springer Online Journal Archives 1860-2000
    Topics: Architecture, Civil Engineering, Surveying
    Notes: Abstract A probability model has been developed to evaluate the effectiveness of fire prevention efforts applied under specific weather conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02098678
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  • 9
    Electronic Resource
    Electronic Resource
    Meal size in nymphs of Locusta migratoria (1972)
    Springer
    Entomologia experimentalis et applicata 15 (1972), S. 399-410 
    Details
    ISSN: 1570-7458
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Die Nahrungsmenge, die von einer Larve der Wanderheuschrecke, Locusta migratoria L., im fünften Entwicklungsstadium bei einer einzigen Mahlzeit verzehrt wird, wurde ermittelt, indem ihr Darm und Darminhalt sofort nach dem Fressen gewogen wurden. In der Mitte des Entwicklungsstadiums wurden größere Mengen verzehrt, Weibchen fraßen mehr als Männchen, jedoch sind die weiblichen Larven ja auch größer. Die Menge der aufgenommenen Nahrung vergrößerte sich mit der Dauer künstlichen Futterentzuges. Sie erreichte ihren Höhepunkt nach sechs Stunden, nach welcher Zeit der Vorderdarm absolut leer war. Die verzehrten Mengen waren je nach der Art der Nahrung unterschiedlich. Auch stellten die Insekten sich so ein, daß sie von einer bestimmten Nahrung mehr zu sich nahmen, wenn sie daran aufgezogen worden waren. Nach längeren Zeitspannen der Isolierung hatten sie die Tendenz, weniger zu fressen. Temperatur und Feuchtigkeit hatten keinen Einfluß auf die Mengen, die verzehrt wurden, außer bei 40°, bei welcher Temperatur sich das gesamte Verhalten zum Fressen ändert.
    Notes: Abstract Meal size in fifth-instar nymphs of Locusta migratoria L. has been investigated by weighing the gut and its contents immediately after feeding. Larger meals are taken in mid-instar, while females eat more in one meal than males under the same conditions. Bigger meals are also eaten after longer periods of food deprivation, but after deprivation for two hours or less, corresponding with the normal interfeed length, meals are smaller than would be expected from the potential maximum foregut volume. The maximum volume attained varies with the type of food available to the insects and is influenced by previous conditioning. Temperature and humidity do not affect meal size except at 40°, at which temperature the usual pattern of feeding is completely altered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00293604
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  • 10
    Electronic Resource
    Electronic Resource
    Pt/Sn bimetallic catalysts for the electro-oxidation of methanol: poisoning by silicate and phosphate unions (1976)
    Springer
    Journal of applied electrochemistry 6 (1976), S. 221-227 
    Details
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The influence of silicate and phosphate anions on the performance of Pt/Sn electrodeposited catalysts for the electro-oxidation of methanol has been studied. Both anions were found to have serious poisoning effects on the catalyst, whereas platinum catalysts were unaffected. The poisoning mechanism in both cases was thought to be initiated by the formation of either stannosilicates or stannophosphates species followed by the build-up of polymeric silicate or phosphate that ultimately blocks the active sites. The origin of the poisoning mechanism in both cases was found to be chemical rather than electrochemical. In the case of silicate, the poisoning species could be removed and the catalytic activity restored by chemical treatment with sulphuric acid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00616144
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