Processing of a Sesquiterpene Lactone by Papilio glaucus Caterpillars

Abstract

Papilio glaucus caterpillars encounter a diverse array of sesquiterpene lactones, including parthenolide, in the leaves of host plants Liriodendron tulipifera and Magnolia virginiana. These compounds are toxic to unadapted herbivores, and the development of P. glaucus caterpillars likely depends on their ability to excrete or detoxify them efficiently. A new metabolite of parthenolide, 2-alpha-hydroxydihydroparthenolide, identified by crystal structure determination and nuclear magnetic resonance, was present in the waste of the caterpillars. The parent compound was modified by the reduction of an alpha-methylene group, rendering the compound less reactive, and the addition of a hydroxyl group, which increases the polarity and prepares it for the conjugation reactions of phase II metabolism. Unmetabolized parthenolide was also present in large amounts in waste. P. glaucus larvae are apparently capable of excreting intact sesquiterpene lactones and sesquiterpene lactone metabolites during consumption of foliage rich in these compounds.

Hybridization leads to host-use divergence in a polyphagous butterfly sibling species pair

“…tulipifera is known to have a wide variety of defensive compounds, particularly sesquiterpene lactones (Lindroth et al 1986;Scriber et al 1987;Barbosa et al 1990), which P. glaucus is capable of handling, but P. canadensis is not (Lindroth et al 1986). The ability of P. glaucus to feed on L. tulipifera appears to be at least partly due to its ability to excrete unaltered sesquiterpene lactones (Frankfater et al 2005). In this study we found the relative growth of the late flight on L. tulipifera was positive, indicating it was a comparatively good host.…”

Novel Weapons Testing: Are Invasive Plants More Chemically Defended than Native Plants?

“…], [ 18], [19,20]. Although preference for plant leaf chemistry in isolation might not reflect herbivore feeding preferences in nature, particularly if extrinsic factors like predation and parasitism shift herbivore feeding to non-preferred host-plants [21], [22], [23], extracts of species known to be utilized by woolly bears in the field were either readily consumed or preferred (e.g., Acer , Eupatorium , Parthenocissus quinquefolia (L.) Planch., Platanus occidentalis ), and caterpillars similarly avoided extracts from native plants known to be chemically defended against generalist Lepidoptera, including paw paw [24], tulip poplar [25], and flowering dogwood [26]. Thus, although other herbivores might respond differently to the same chemistry, our laboratory assays isolating plant chemistry alone reflected known woolly bear feeding preferences in nature.…”

Impacts of climate warming on hybrid zone movement: Geographically diffuse and biologically porous “species borders”

“…In more than 40 000 multichoice oviposition events of the polyphagous North American P. glaucus and P. canadensis , the primary difference was limited to a Z‐linked shift in host rank hierarchy caused by acceptance of quaking aspen (Salicaceae) and reduced specificity for tulip tree (Magnoliaceae, Mercader & Scriber, 2005, 2007; Mercader et al ., 2008) which is toxic to P. canadensis and P. troilus groups (Nitao et al , 1991b; Scriber et al , 1991a; Frankfater et al , 2005). A lack of the Z‐linked aspen acceptance (Scriber et al , 1991b) in the allochronically distinct hybrid swarm late flight (Scriber et al , 2008a; Ording et al , 2010) was found, probably due to introgression from the parental, P. glaucus (Mercader & Scriber, 2007, 2008b; Fig.…”