Larval Feeding Stimulants for a Rutaceae-Feeding Swallowtail Butterfly, Papilio xuthus L. in Citrus unshiu Leaves

Abstract

Larvae of a swallowtail butterfly, Papilio xuthus L., feed exclusively on plants of the family Rutaceae, including various Citrus crops. Larvae were strongly stimulated to feed on paper strips impregnated with ethanolic extracts of host-plant leaves. Stimulation of feeding on extracts of Citrus unshiu leaves required a mixture of chemicals including sugars (D: -glucose, D: -fructose, and D: -sucrose), a betaine [(-)-stachydrine], a cyclic peptide (citrusin I), a polymethoxyflavone (isosinensetin), and the lipids 1-linolenoylglycerol, 1-linoleoylglycerol, 1-octadecenoylglycerol, 1-stearoylglycerol, and 1,2-dilinolenoyl-3-galactosyl-sn-glycerol. When these compounds were assayed individually, few larvae consumed test strips. However, larvae readily chewed the test strips treated with a mixture of all compounds, indicating that host recognition by P. xuthus larvae is mediated by a specific combination of both primary and secondary substances. Comparison of 11 stimulant components with 10 compounds from C. unshiu leaves previously reported as stimulant components for oviposition by P. xuthus adult females revealed only one compound, stachydrine, as an ingredient in common. While the larval feeding-stimulant mixture is dominated by nutrients and other compounds of general significance for primary metabolism, the component oviposition stimulants are mostly secondary substances, including flavonoid glycosides, protoalkaloids, a cyclitol, and a betaine, that have restricted distributions in plants. Reliance by adult females on unique profiles of secondary compounds presumably reflects the need to locate and recognize specific host-plant species within a diverse flora. Since the initial host choice for the larvae is made typically by the ovipositing female, however, unique secondary compounds may be less important for larval feeding than are compounds useful for indicating food and microhabitat quality once on the host plant.

Chemical ecology of insect–plant interactions: ecological significance of plant secondary metabolites

“…1). 22) The larvae readily consumed the test strips treated with a mixture of all the 11 compounds, while very few larvae consumed the strip when each compound was tested alone, indicating that host recognition by P. xuthus larvae is mediated by a specific combination of both primary and secondary metabolites. This result is in contrast to the 10 oviposition stimulant components of P. xuthus contained in the same host species (C. unshiu) in which only one compound, stachydrine (10), was an ingredient in common.…”

Isolation and Characterization of Host Recognition Cues in Corn Roots for Larvae of the Western Corn Rootworm (Coleoptera: Chrysomelidae)

“…One structural species of MGDG (1,2-dilinolenoyl-3-galactosyl-sn-glycerol) is reported to be a constituent of a 13-component blend that stimulates feeding by larvae of the swallowtail butterßy, Papilio xuthus L. (Murata et al 2011). It is notable that the active feeding blend for the lepidopteran larva also contains three of the monosaccharides (glucose, sucrose, and fructose) that we identiÞed in the F-1 fraction isolated from corn roots.…”

Optimization an Optimal Artificial Diet for the Predatory Bug Orius sauteri (Hemiptera: Anthocoridae)

“…It also appears from our results that providing saccharides enables the high energy demands of mating to be met successfully. Sucrose is an efficient component in many artificial diets for the mass rearing of arthropods, where it is used as a feeding stimulant [54]. Insect components are necessary for mass rearing of arthropods although the research of insect artificial diet has been carried out for a long period of time [40].…”