Document Detail


Biparental endowment of endogenous defensive alkaloids in Epilachna paenulata.
MedLine Citation:
PMID:  19052820     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Coccinellid beetles contain a variety of defensive alkaloids that render them unpalatable to predators. Epilachna paenulata (Coleoptera: Coccinellidae) is a South American ladybird beetle that feeds on plants of the Cucurbitaceae family. The defensive chemistry of E. paenulata has been characterized as a mixture of systemic piperidine, homotropane, and pyrrolidine alkaloids. Whole body extracts of adult beetles contain four major alkaloids: 2-(2'-oxopropyl)-6-methylpiperidine (1); 1-(6-methyl-2,3,4,5-tetrahydro-pyridin-2-yl)-propan-2-one (2); 1-methyl-9-azabicyclo[3.3.1]nonan-3-one (3); and 1-(2''-hydroxyethyl)-2-(12'-aminotridecyl)-pyrrolidine (4). Comparative studies of the defensive chemistry of eggs, larvae, pupae, and adults showed differences in alkaloid composition and concentration among life stages. While adults contained mainly the homotropane 1-methyl-9-azabicyclo[3.3.1]nonan-3-one (3), eggs showed the highest concentration of the piperidine 2-(2'-oxopropyl)-6-methylpiperidine (1). We studied the origin of this alkaloid in the eggs by feeding newly emerged, virgin adult beetles with [2-(13)C]-labeled acetate, and by performing crosses between (13)C-fed and unlabeled males and females. GC-MS analysis of alkaloids from (13)C-fed males and females showed high incorporation of (13)C into the alkaloids, as evidenced from a 20-30% increase of isotopic peaks in diagnostic fragment ions, confirming the expected endogenous origin of these alkaloids. In addition, analyses of eggs from different crosses showed that labeled alkaloids from both parents are incorporated into eggs, indicating that E. paenulata males transfer alkaloids to the females at mating. Biparental endowment of chemical defenses into eggs has been shown previously in insects that acquire defensive compounds from dietary sources. To our knowledge, this is the first report of biparental egg endowment of endogenous defenses.
Authors:
Soledad Camarano; Andrés González; Carmen Rossini
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2008-12-04
Journal Detail:
Title:  Journal of chemical ecology     Volume:  35     ISSN:  1573-1561     ISO Abbreviation:  J. Chem. Ecol.     Publication Date:  2009 Jan 
Date Detail:
Created Date:  2009-02-02     Completed Date:  2009-05-19     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7505563     Medline TA:  J Chem Ecol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1-7     Citation Subset:  IM    
Affiliation:
Departamento de Química Orgánica, Universidad de la República, Montevideo, Uruguay.
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MeSH Terms
Descriptor/Qualifier:
Alkaloids / analysis*,  metabolism
Animals
Beetles / metabolism*
Carbon Isotopes
Female
Gas Chromatography-Mass Spectrometry
Hemolymph / chemistry
Larva / chemistry
Male
Ovum / chemistry
Pupa / chemistry
Sex Factors
Sodium Acetate / analysis
Chemical
Reg. No./Substance:
0/Alkaloids; 0/Carbon Isotopes; 6131-90-4/Sodium Acetate

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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