Differential responses of tiger swallowtail subspecies to secondary metabolites from tulip tree and quaking aspen

Abstract

Two subspecies of the eastern tiger swallowtail butterfly, Papilio glaucus, exhibit reciprocal inabilities to survive and grow on each other's preferred foodplant. P. g. canadensis R. & J. performs well on quaking aspen (Populus tremuloides Michx.) but not on tulip tree (Liriodendron tulipifera L.); P. g. glaucus L. performs well on tulip tree but not on quaking aspen. This study was designed to test the hypothesis that secondary metabolites in tulip tree and quaking aspen are responsible for these differential utilization abilities. We extracted and fractionated leaf constituents into different chemical classes, applied them to a mutually acceptable diet (black cherry, Prunus serotina, leaves), and bioassayed them against neonate larvae (survival) and penultimate instar larvae (survival, growth, digestibility and conversion efficiencies). For each plant species, one fraction in particular showed activity against the unadapted subspecies. One tulip tree fraction dramatically reduced survival of P. g. canadensis neonates, and reduced consumption rates, growth rates, and ECI's of fourth instar larvae. The tulip tree constituents most likely responsible for these effects are sesquiterpene lactones. One quaking aspen fraction greatly lowered survival of P. g. glaucus neonates, and decreased survival, consumption rates, growth rates and ECD's of fourth instar larvae. The compounds responsible for these results are probably simple phenols or phenolic glycosides. Surprisingly, P. g. glaucus and P. g. canadensis showed slightly poorer performance on the active tulip tree and quaking aspen fractions, respectively, indicating that even adapted insects incur a metabolic cost in the processing of their host's phytochemicals.

Partitioning of 14 C-labeled photosynthate to allelochemicals and primary metabolites in source and sink leaves of aspen: evidence for secondary metabolite turnover

“…Leaf samples (7±20 mg) were separated into ten phytochemical fractions representing growth and metabolism (lipids plus pigments, amino acids, organic acids, protein, residue), storage and transport (starch and sugars), and carbon-based defenses (phenolic glycosides, methanol:water-soluble tannins/phenolics and acetone-soluble tannins/phenolics) using a modi®ed sequential extraction method (Dickson 1979;Lindroth et al 1986; Mauette and Oechel 1987; Fig. 1).…”

Iridoid glycosides and insect feeding preferences: gypsy moths (Lymantria dispar, Lymantriidae) and buckeyes (Junonia coenia, Nymphalidae)

“…as well as insect growth and survival (e.g. Lincoln et al, 1982;Lindroth et al, 1986;Seiber et af., 1980). However, the impact of such chemical variation on insect feeding behaviour and preferences may depend on whether the insect is a generalist or a specialist feeder (Kraft & Denno, 1982;.…”

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

“…3). The ability of Papilio canadensis to consume Populus tremuloides appears to be primarily based on the ability to detoxify phenolic glycosides by high esterase activity (Lindroth et al 1986(Lindroth et al , 1988Scriber et al 1989). Studies using backcrosses between Papilio glaucus and Papilio canadensis have indicated that the ability to use Populus tremuloides acts in a dose-dependent manner, where hybrids have intermediate abilities to detoxify these compounds (Scriber et al 1989(Scriber et al , 1999, as is also seen in these natural hybrid populations.…”

“…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).…”