ISSN:
1573-1561
Keywords:
Cynoglossum officinale
;
Boraginaceae
;
pyrrolizidine alkaloids
;
chemical defense
;
specialist herbivores
;
generalist herbivores
;
Ethmia bipunctella
;
Mogulones (Ceutorhynchus) cruciger
;
Spodoptera exigua
;
Helix aspersa
;
Frankliniella occidentalis
;
Locusta migratoria
;
Lyriomyza trifolii
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract In this study we tested whether pyrrolizidine alkaloids (PAs) ofCynoglossum officinale serve as antifeedants against herbivores. Total PA N-oxide extracts of the leaves significantly deterred feeding by generalist herbivores. Specialist herbivores did not discriminate between food with high and low PA levels. Three PAs fromC. officinale, heliosupine, echinatine, and 3′-acetylechinatine, equally deterred feeding by the polyphagous larvae ofSpodoptera exigua. Although the plants mainly contain PAs in their N-oxide form, reduced PAs deterred feeding byS. exigua more efficiently than PA N-oxides. On rosette plants, the monophagous weevilMogulones cruciger significantly consumed more of the youngest leaves, which had the highest PA level and the highest nitrogen percentage. Larvae ofEthmia bipunctella, which are oligophagous within the Boraginaceae, did not discriminate between leaves. All generalist herbivores tested significantly avoided the youngest leaves with the highest PA levels. In the field, the oldest leaves also were relatively more damaged by herbivores than the youngest leaves. It is hypothesized that the skewed distribution of PAs over the leaves of rosette plants reflects optimal defense distribution within the plant.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02033698
