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  • 1
    ISSN: 1420-9098
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Resume Les effets dûs à la taille du groupe, à l'époque de l'année et aux proportions initiales de soldats ont été explorés dans des groupes expérimentaux deReticulitermes flavipes (Kollar) et deReticulitermes virginicus (Banks). On a élevé des groupes en laboratoire pedant 12 semaines. Les petits groupes (de 500 à 1000 ouvriers) ont produit un plus faible pourcentage de soldats que les grands groupes (de 1500 à 2000 ouvriers). Le nombre de soldats produits dans un groupe est hautement corrélé au nombre total de termites qui survivent. Le pourcentage moyen observé dans tous les groupes a été de 1,75 pour les 2 espèces étudiées. La production de soldats chezReticulitermes flavipes a été la plus élevée dans les colonies prélevées en avril (2%) et la plus faible dans celles prélevées en octobre (0,38%). Les observations bimensuelles des augmentations et des baisses de production de soldats montrent qu'il y a un cycle saisonnier du potentiel de développement. La présence de soldats dans les groupes inhibe la production de nouveaux soldats. Un pourcentage anormalement élevé de soldats n'a pas provoqué l'élimination massive de soldats. De plus, la surcharge des groupes en soldats (plus de 1,75%) n'a pas affecté de façon nuisible la survie du groupe.
    Notes: Summary The effects of group size, time of year, and initial proportions of soldiers were explored in experimental groups ofReticulitermes flavipes (Kollar) andR. virginicus (Banks). Groups were held in the laboratory for 12 weeks. Small groups (500 to 1000 workers) produced a smaller percentage of soldiers than did larger groups (1500 to 2500 workers). The number of soldiers produced in a group is highly correlated with the total number of termites surviving. The average percentage produced for all group sizes was 1.75 for both species. Production of soldiers inR. flavipes was highest in colonies collected in April (2.0%) and lowest in those collected in October (0.38%). Bimonthly observations of increases and decreases in soldier production indicate a seasonal cycle in developmental potential. Presence of soldiers in groups inhibited the production of new soldiers. An abnormally high percentage of soldiers did not precipitate extensive elimination of soldiers. In addition, overloading groups with soldiers (more than 1.75%) did not adversely affect group survival.
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  • 2
    ISSN: 1432-136X
    Keywords: Thermoregulation ; Prostaglandins ; Eicosanoids ; Body temperature ; Cicada, Tibicen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Cicadas prevent body temperature from exceeding tolerable levels by a combination of behavioral responses and sweating. Sweating is activated when body temperature reaches a critical set-point temperature. We investigated control of sweating in the cicada, Tibicen dealbatus, by chemically manipulating biosynthesis of prostaglandins and other eicosanoids. Injecting prostaglandins in amounts equal to those that induce behavioral fever in scorpions and crustaceans resulted in only a small increase in set-point temperature. Blocking prostaglandin biosynthesis with cyclo-oxygenase inhibitors such as aspirin produced significant changes in set-point temperature, confirming that prostaglandins are involved in control of sweating. However, the effect of cyclo-oxygenase inhibitors was not the opposite of the effect of prostaglandins. Instead, the effect of cyclo-oxygenase inhibitors depended strongly on the value of setpoint temperature prior to treatment. Results of biochemical manipulations of other steps in eicosanoid biosynthetic pathways corroborated the results of cyclo-oxygenase inhibition and indicated that eicosanoids other than prostaglandins may be involved in control of body temperature in normothermic T. dealbatus. The effect of cyclo-oxygenase inhibitors on a given set-point temperature depended on the ambient temperature experienced by cicadas during the experiment. Surprisingly, cicadas exposed to ambient temperatures ≥40°C delayed activation of sweating until body temperature exceeded values normally recorded from T. dealbatus in the field. Control of body temperature in normothermic cicadas is thus complex, involving inputs from body temperature sensors, ambient temperature sensors, and at least two cyclo-oxygenase-dependent regulatory pathways.
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  • 3
    ISSN: 1573-1561
    Keywords: Philantus ; beewolf ; Sphecidae ; Hymenoptera ; pheromones ; scentmarking ; tridecanone ; pentadecanone ; heptadecanone ; hexadecanoic acid ; ethyl hexadecanoate ; octadecanoic acid ; ethyl octadecanoate ; mandibular glands ; wasps
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Observations of wasp behavior indicate that male beewolves,Philanthus basilaris andP. bicinctus apply a “marking pheromone” to the leaves and stems of plants within their territories. We now provide direct evidence for the presence of volatile chemicals in the paired mandibular glands of the males, provide preliminary identification of these volatiles, and show that all of the volatile chemicals in the mandibular glands are present on freshly marked plant surfaces but are absent from unmarked plants. Pyrazines, which have been reported in other species of aculeate wasps including the EuropeanPhilanthus triangulum, were not found inP. basilaris orP. bicinctus.
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  • 4
    ISSN: 1573-1561
    Keywords: Philanthus ; Hymenoptera ; Sphecidae ; pheromone ; scent-marking ; 2-alkanones ; fatty acids ; ethyl esters ; alkenals ; N,N-dimethylhy-drazine ; methyl esters ; EI-MS ; CI-MS ; methoxymercuration ; methylthiolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Detailed chemical characterizations are provided for the species-specific mixtures of marking pheromones utilized by the male beewolvesPhilanthus basilaris andP. bicinctus. Successful analysis of these complex mixtures of 2-ketones, fatty acids, ethyl esters, and aldehydes was facilitated by the treatment of the crude extracts with 1,1-dimethylhydrazine and direct analysis of the resulting hydrazones, methyl esters, and starting ethyl esters by GC-MS.
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  • 5
    ISSN: 1573-1561
    Keywords: Philanthus crabroniformis ; Philanthus barbatus ; Philanthus pulcher ; Hymenoptera ; Sphecidae ; beewolf ; mandibular glands ; pheromones ; semiochemicals ; mass spectrometry ; infrared spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The composition of the territorial marking pheromones from mandibular glands of males of the beewolvesPhilanthus crabroniformis, P. barbatus, andP. pulcher have been determined. The structures of the components were elucidated by gas chromatography-mass spectrometry and gas chromatography-Fourier transform infrared spectroscopy. The major compound ofP. crabroniformis is isopropyl tetradecanoate, with somewhat lesser amounts of 2-tridecanone, 3-methyl-3-butenyl tetradecanoate, and 92∶8 (Z)∶(E)-11-eicosen-1-ol. The major compounds ofP. barbatus are ethyl tetradecanoate and hexadecanal, which are present in approximately a 60∶40 ratio. These two compounds comprise over 95% of the neutral lipids. Also present in lesser amounts are ethyl dodecanoate, tetradecanal, hexadecan-1-ol, a Δ x -octadecen-1-ol, and octadecan-1-ol. The major compounds ofP. pulcher are ethyl (Z)-7-hexadecenoate and geranylgeraniol acetate, which comprise nearly 90% of the neutral lipid fraction, with smaller amounts of tetradecanal, pentadecanal, and ethyl hexadecanoate; trace amounts of Δ x hexadecenal, hexadecanal, and octadecanal are also present.
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  • 6
    ISSN: 1573-1561
    Keywords: Monomorium spp. ; Hymenoptera ; Formicidae 2,5-dialkylpyrrolidines ; ant venom alkaloids ; methoxymercuration-demercuration ; chemotaxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A comparative analysis of the venomous alkaloids produced by ant species in the subgenusMonomorium of the genusMonomorium has been undertaken. All species produce mixtures of unsymmetricaltrans-2,5-dialkylpyrrolidines, but the proportions of the constituents may vary considerably between species. All alkaloids contain both C6 and C9 side chains which are present as C9-saturated. C6-monounsaturated, and both C6-and C9-monounsaturated dialkylpyrrolidines. The structure of 2-(1-hex-5-enyl)-5-(1-non-8-enyl)pyrrolidine, a previously undescribed alkaloid, was proved by unambiguous synthesis after the location of the double bonds was established by the methoxymercuration-demercuration followed by mass spectrometry. The possible chemotaxonomic significance of the mixtures of venomous alkaloids produced by these species ofMonomorium is discussed.
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  • 7
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Entomology 27 (1982), S. 149-172 
    ISSN: 0066-4170
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology
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  • 9
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    Unknown
    In:  Other Sources
    Publication Date: 2012-05-18
    Description: Reliability achievement in VTOL automatic control systems
    Keywords: AIRCRAFT
    Format: text
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  • 10
    Publication Date: 2001-11-01
    Print ISSN: 1467-7873
    Topics: Chemistry and Pharmacology , Geosciences
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