Glucosinolates and trichomes track tissue value in two sympatric mustards.

Glucosinolates, trichomes, nitrogen, and carbon are not distributed uniformly through the canopies of mustards. In this study, we asked whether glucosinolate concentrations and trichome densities in two sympatric mustards, Brassica kaber and B. nigra, are highest in tissues of greatest value to the plant.

From terpenoids to aliphatic acids: further evidence for late-instar switch in osmeterial defense as a characteristic trait of swallowtail butterflies in the tribe papilionini.

We compared the chemical compositions of the osmeterial secretions of fourth and fifth (last) instars of eight swallowtail species of the tribe Papilionini. Four species (Papilio demoleus, P. polytes, P.

Combined roles of contact stimulant and deterrents in assessment of host-plant quality by ovipositing zebra swallowtail butterflies.

Zebra swallowtail (Eurytides marcellus) butterflies are stimulated to oviposit by a single compound, 3-caffeoyl-muco-quinic acid (1). Analysis of the aqueous extracts of the leaves of the host. Asimina triloba, showed that they contained stimulant 1, its isomer (2), and the flavonoids rutin (3) and nicotiflorine (4) as major components.

Quantification of contact oviposition stimulants for black swallowtail butterfly,Papilio polyxenes, on the leaf surfaces of wild carrot,Daucus carota.

Ovipositing black swallowtail butterflies,Papilio polyxenes, make their final host-selection decisions on the basis of compounds present on the leaf surface. Little information is available, however, on the chemistry of leaf surfaces. The purpose of this study was to develop a technique to extract and quantify the concentrations of compounds from the leaf surfaces ofDaucus carota, one of the main host species forP.

Aristolochic acids fromThottea spp. (Aristolochiaceae) and the osmeterial secretions of Thottea-feeding troidine swallowtail larvae (Papilionidae).

Two aristolochiaceous plants in the genusThottea were shown to contain aristolochic acids. Larvae of two Malaysian troidine swallowtail butterflies,Troides (Troides) amphrysus andPachliopta (Losaria) neptunus, that fed onThottea leaves were found to sequester corresponding aristolochic acid analogs in the osmeterial glands.

Oviposition stimulants for the black swallowtail butterfly: Identification of electrophysiologically active compounds in carrot volatiles.

Headspace volatiles were collected from undamaged foliage of carrot,Daucus carota, a host-plant species of the black swallowtail butterfly,Papilio polyxenes. The volatiles were fractionated over silica on an open column, and the fractions were tested in behavioral assays withP. polyxenes females in laboratory experiments.

D-(+)-Pinitol, an oviposition stimulant for the pipevine swallowtail butterfly,Battus philenor.

Oviposition by females of the pipevine swallowtail butterfly,Battus philenor, was stimulated by contact with alcoholic extracts of host foliage.D-(+)-Pinitol was isolated and identified from leaf material of one host species,Aristolochia macrophylla (Aristolochiaceae). In combination with chloroform-soluble components of host leaf material, this compound was comparable to the parent extract in stimulating oviposition.

Effects of benzylisoquinoline alkaloids on the larvae of polyphagous Lepidoptera.

Six benzylisoquinoline alkaloids were fed to the larvae of three polyphagous Lepidoptera species: Hyphantria cunea, Spodoptera eridania, and Lymantria dispar. Exposure of last instar larvae to alkaloid-containing diets over a 24-h period resulted in reduced feeding rates and reduced growth efficiencies. Lymantria dispar larvae reared from eggs on alkaloid diets took longer to reach the fifth instar, attained lower larval weights, and showed reduced survivorship.

Toxicity of angular furanocoumarins to swallowtail butterflies: escalation in a coevolutionary arms race?

Xanthotoxin, a linear furanocoumarin occurring in many plants of the family Umbelliferae, is not appreciably toxic to the umbellifer-feeding larvae of Papilio polyxenes (Lepidoptera; Papilionidae), whereas angelicin, an angular furanocoumarin found only in a few relatively advanced tribes of the Umbelliferae, reduces growth rate and fecundity. The biosynthetic pathway leading to angular attachment of the furan ring may thus have been a response within the Umbelliferae to selective pressures exerted by specialized herbivores that had adapted to feeding on linear furanocoumarins.

Allylglucosinolate and herbivorous caterpillars: a contrast in toxicity and tolerance.

Allylglucosinolate, found in many cruciferous plants, is acutely toxic to Papilio polyxenes larvae, which do not normally attack crucifers. By contrast, larval growth of Pieris rapae, a crucifer specialist, is not affected even by artificially high concentrations of allylglucosinolate. Larval growth of Spodoptera eridania, a generalist feeder, is inhibited by high but not by low concentrations of the compound.

Sodium: stimulus for puddling behavior by tiger swallowtail butterflies, Papilio glaucus.

Male Papilio glaucus butterflies are attracted to sand soaked with dillute aqueous solutions of sodium salts. A sodium ion concentration of 10(-3) molar is sufficient to stimulate puddling behavior. Acqlisition of sodiumn mnay be the main ecological function of pudding behavior.

L-dopa in legume seeds: a chemical barrier to insect attack.

Seeds of the genus Mucuna display both a remarkable immunity to attack by seed-eating insects and an unustially high concentration of free L-dopa. When seed powders or pure L-dopa were incorporated into artificial diets and fed to southern armyworm larvae, mortality increased, and abnormal pupae and adults resulted. At higher concentrations L-dopa acted as a feeding repellent.

Detoxication enzymes in the guts of caterpillars: an evolutionary answer to plant defenses?

Higher activity of midgut microsomal oxidase enzymes in polyphagous than in monophagous species indicates that the natural function of these enzymes is to detoxify natural insecticides present in the larval food plants. Differing strategies of adaptation to plant defenses may partly account for the great diversity of insect herbivores.