par Duffey, Sean;Pasteels, Jean Lambert 
Référence Physiological entomology, 18, 2, page (119-129)
Publication Publié, 1993
Référence Physiological entomology, 18, 2, page (119-129)
Publication Publié, 1993
Article révisé par les pairs
| Résumé : | Abstract. The uptake of hypericin from the foliage of Hypericum perforatum by four species of adult chrysomelid beetles, Chrysolina brunsvicensis, C. geminata, C. hyperici and C. varians, was investigated under laboratory conditions. In no species were detectable levels of hypericin passed from the larval to the pupal or adult stages. The total amount of hypericin found in the adult beetles was positively related to the rate of ingestion of foliage. When feeding activity lessened or ceased, body levels of hypericin declined. In adults of C. brunsvicensis, C. hyperici and C. varians maximal body levels of hypericin occurred after 1–10 days of feeding. In C. brunsvicensis a maximal average level of c. 0.96 μg/beetle was obtained. After 20 days body levels in C. brunsvicensis declined to nearly zero. Adults of C. brunsvicensis contained more hypericin than the other species of beetles, but in no case was enough hypericin sequestered to match the original values (c. 13.3 μg/beetle) published by Rees (1969). Our results caste doubt on the role of hypericin as a sequestered defence against predators. Analysis of body distribution of hypericin indicated the majority was in the gut lumen (80%). An input‐output analysis of hypericin ingested by adults of C. brunsvicensis showed that the greatest majority of hypericin was eliminated in the faeces (up to 85%). Between 15% and 35% of the ingested hypericin was unaccounted for. This loss is the result of a post‐defecational degradation of hypericin (perhaps bacterial). Copyright © 1993, Wiley Blackwell. All rights reserved |
