ISSN:
1573-1561
Keywords:
Variation in cardenolides
;
Oncopeltus fasciatus
;
Lygaeus kalmii kalmii
;
milkweeds
;
Asclepias
;
chemical defense
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract A colorimetric assay was used to quantify the amount of cardenolides in the lygaeid bugsOncopeltus fasciatus andLygaeus kalmii kalmii and their milkweed host plants (Asclepias spp.) in central California. The cardenolide content of individual insects, determined in microgram equivalents of digitoxin, varied from zero to over 300 μg per insect. Sources of variation of cardenolide content in the insects include interspecific and intraspecific differences in the content of the host plant species and also differences in the content of plant organs on which insects were feeding. This last source of variability may explain temporal variation in the cardenolide content of the insects. Adults ofO. fasciatus, which migrate into California in the late spring and early summer, and adults ofL. k. kalmii, which emerge from winter hibernacula in the early spring, contained small to immeasureable amounts of cardenolides. The colonization pattern ofO. fasciatus on species ofAsclepias in north central California suggests that this species does not maximize its opportunities to sequester large quantities of cardenolides from potential hosts. The emetic potential of lygaeids in California to vertebrate predators is briefly discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00988061
Permalink
