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2001 (1)
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1984 (1)
1Author    Reinhold DemRequires cookie*
 Title    Influence of Food and Larval Age on the Defensive Chemistry of Satumia pyri  
 Abstract    Scolus secretions and hemolymph of caterpillars of Satumia pyri fed with two different foodplants (Crataegus m onogyna, Prunus spinosa) were chemically analyzed and their chemi­ cal similarities determined. The secondary-compound patterns obtained for the two body fluids showed no significant differences when compared between the two groups of alterna­ tively fed last-instar larvae. Thus, the composition of these fluids of full-grown caterpillars is not influenced by the larval diet. However, younger larvae on P. spinosa revealed a diversity of compounds differing significantly from that of larger caterpillars fed with either C. m ono­ gyna (both body fluids) or P. spinosa (hemolymph only). This indicates that, on the one hand, the hemolymph composition is adapted to the changing physiological requirements of the given instars whereas, on the other hand, the defensive mixtures remain unaltered in the late larval instars due to a constant spectrum of potential enemies. 
  Reference    Z. Naturforsch. 56c, 89—94 (2001); received September 12/October 18 2000 
  Published    2001 
  Keywords    Chemical Defense, Saturniidae, Secondary Compounds 
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 TEI-XML for    default:Reihe_C/56/ZNC-2001-56c-0089.pdf 
 Identifier    ZNC-2001-56c-0089 
 Volume    56 
2Author    Karl-Heinz TomaschkoRequires cookie*
 Title    Defensive Secretion of Ecdysteroids in Pycnogonum litorale (Arthropoda, Pantopoda)  
 Abstract    In response to disturbance, the pycnogonid Pycnogonum litorale discharges a mixture o f eight ecdysteroids (ES). Repeated intensive m olestation causes 99% secretion o f the endogenous ES present. The concentration o f the total ES in the defensive effluent is 1.0 x 10" 3 m o lT '1. 20-Hydroxyecdysone 22-acetate, the predominant ES, reaches 0.8 x 10" 3 m ol T_1. This is sufficient to deter significantly feeding by the com m on shore crab Carcinus maenas, a generalist predator in the habitat o f the pycnogonid. There is evidence that the secreted ES o f P. litorale contribute to its unpalatability. The present paper describes for the first time defensive secretion in marine arthropods. 
  Reference    Z. Naturforsch. 49c, 367—371 (1994); received February 10 1994 
  Published    1994 
  Keywords    Pycnogonids, Pycnogonum litorale, Ecdysteroids, Defensive Secretion, Chemical Defense 
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 TEI-XML for    default:Reihe_C/49/ZNC-1994-49c-0367.pdf 
 Identifier    ZNC-1994-49c-0367 
 Volume    49 
3Author    Michael WinkRequires cookie*
 Title    Chemical Defense of Lupins. Mollusc-Repellent Properties of Quinolizidine Alkaloids  
 Abstract    Polyphagous molluscs such as H elix pom atia and Arion rufus generally do not feed on plants containing alkaloids. O f 19 species tested 10 species were totally avoided, the other 9 species were less attacked than Lactuca sativa, which was readily taken. Plants containing quinolizidine alkaloids were studied in detail. Those species with the a-pyridone alkaloids cytisine and N-methylcytisine were avoided to a higher extent than plants with lupanine as the major alkaloid. Since the repellency observed could be due to other natural products present in the plants besides the alkaloids, the feeding response o f H elix pom atia was tested on artificial diets containing quinolizidine alkaloids in various concentrations as the only variable. If the snails had the choice they clearly preferred alkaloid-free food or a diet with only low alkaloid concen­ trations. Half-maximal repellency o f cytisine is less than 2 m M , o f sparteine 1 -5 m M , and o f lupanine 1 -8 mM. Since the in vivo concentrations o f sparteine, cytisine, and lupanine are equal to or higher than the inhibitory concentrations required it is concluded that quinolizidine alkaloids constitute a potential antimolluscan principle o f legum es. 
  Reference    Z. Naturforsch. 39c, 553 (1984); received March 22 1984 
  Published    1984 
  Keywords    Quinolizidine Alkaloids, M ollusc Repellency, C oevolution, Plant-H erbivore Interaction, Snails, Chemical Defense 
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 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0553.pdf 
 Identifier    ZNC-1984-39c-0553 
 Volume    39