Short Communicationsthey behave as if stimulated sexually by the flower labellum.Analyses of volatiles from O. litigiosa flowers 2o indicate the presence of citronellyl and farnesyl esters. These are biochemically closely related to geranyl esters and thus might be responsible for the attraction of male elaterid beetles to various Ophrys flowers.1 Financial assistance was donated by The Bank of Sweden Tercentenary Foundation and the Axel and Margaret Ax:son Jol~nson Foundation. We thank B. Baur for statistical advice.Summary. Two phenylpropanoid compounds, 2-allyl-4,5-dimethoxyphenol(II) and coniferyl alcohol(III), were characterized from body tissue of wild males of the Oriental fruit fly, Dacus dorsal&. These compounds accumulated in the rectal glands only when laboratory-reared males were fed with methyl eugenol. Compound II was released into the air during dusk, which coincides with the fly courtship period. Pheromonal and allomonal effects of the phenylpropanoids were examined. The clerid beetle, Thanasimus formicarius, is attracted to the pheromone of the ambrosia beetle,Summary. Sticky traps containing (+)-lineatin, the pheromone of the ambrosia beetle, Trypodendron lineatum, attracted the predator Thanasimus formicarius to about the same extent as traps baited with ipslure, the pheromone blend used for mass-trapping Ips typographus. The results indicate that T. lineatum is an important prey for T. formicarius early in the season before the main prey becomes active. Addition of exo-brevicomin to ipslure and ethanol and/or c~-pinene to (+)-lineatin did not significantly influence the catches of the predator.

Males of a giant danaine butterfly,Idea leuconoe, display hairpencils during courtship. The females were visually attracted to and olfactorily arrested by an artificial butterfly model to which male hairpencil extracts were added. The hairpencil extracts contained a complex mixture of volatiles, including pyrrolizidine alkaloid (PA) derivatives (danaidone, viridifloric β-lactone), aromatics (phenol,p-cresol, benzoic acid), terpenoids (geranyl methyl thioether, (E,E)-farnesol), a series of γ-lactones (6-hydroxy-4-undecanolides and its homologs), hydrocarbons [(Z)-9-tricosene, etc.], and several compounds with higher molecular weight. A mixture of the major volatiles applied to a butterfly dummy strongly elicited an abdomen-curling acceptance posture in females. Viridifloric β-lactone and danaidone induced significant electroantennogram responses on the female's antennae, suggesting their principal role together with other hairpencil components as a sex pheromone to seduce females.I. leuconoe males seem to acquire the precursor for both of the PA fragments from the host plant,Parsonsia laevigata (Apocynaceae), during the larval stage; thereby they do not show pharmacophagous behavior towards PA-containing plants during the adult stage. However, males are pharmacophagously attracted to and feed on a number of simple phenolic compounds in a manner similar to other danaine species towards PAs. Wild males sequester one of the phagostimulants, (-)-mellein, in the hairpencils in varying quantities. Phenolic compounds incorporated in the hairpencils may act primarily as warning odors linked with the defensive PAs present in the body tissues.

Several pharmacophagous insects have been shown to sequester specific kairomonal substances or their derivatives in their body tissues. Turnip sawflies,Athalia rosae, visit a plant,Clerodendron trichototmum (Verbenaceae), and feed voraciously on the leaf surface. Clerodendrins were characterized as the potent phagostimulants forA. rosae adults. The insect sequesters some of the analogs and becomes extremely bitter on its body surface. Some chrysomelid leaf beetles associated with cucurbitacins were found to store high concentrations of these bitter principles in their body. South American polyphagous beetles,Diabrotica speciosa andCerotoma arcuata, are strongly arrested by root components from the cucurbit plant,Ceratosanthes hilariana, and selectively accumulate 23,24-dihydrocucurbitacin D, effectively gaining bitterness. Similarly, four species of Asian pumpkin leaf beetles belonging to the genusAulacophora were shown to sequester the same compound in body tissue as the major bitter principle. Three phenylpropanoids closely related to methyl eugenol were found to accumulate in the rectal glands of the male Oriental fruit fly,Dacus dorsalis. One of the rectal gland components, 2-allyl-4,5-dimethoxyphenol was shown to be released in the air during courtship. In all of these cases, selectively sequestered compounds strongly deterred feeding by some predators, thus serving as allomones in this context. Kairomonal and pheromonal functions linked with allomonal sequestration by pharmacophagous feeding has also been suggested.

Oviposition stimulants of an Aristolochiaceae-feeding swallowtail butterfly,Atrophaneura alcinous, were isolated from the leaves ofAristolochla debilis and characterized as a mixture of aristolochic acids and sequoyitol. An artificial blend of these components applied to filter paper induced a significant oviposition response by the female butterflies, identical to that elicited by intact leaves of theAristolochia host plant.

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