Yasumasa Kuwahara

Unusual periodicity of sex pheromone production in the large black chaferHolotrichia parallela

Abstract(R)-(−)-Linalool was identified as a minor component sex pheromone of the scarab beetleHolotrichia parallela (Coleoptera: Scarabaeidae). Field evaluations revealed that, although not attractive per se, (R)-(−)-linalool enhances the attractiveness of the major sex pheromone,L-isoleucine methyl ester (LIME). Analyses of the pheromone titers in the glands of field-collected females demonstrated the occurrence of peak levels of 48-hr (“circabidian”) periodicity. The levels of LIME in the glands of 45-day-old virgin females increased over three times from the scototo the photophase of a calling day, but the amounts of (R)-(−)-linalool did not significantly change. Virgin females had in average two times more LIME and 3.6 times more (R)-(−)-linalool than the average amount found in the field-captured beetles throughout the season.

An amino acid derivative as the sex pheromone of a scarab beetle

Since the identification of bombykol, a myriad of compounds have been reported as sex pheromones. Nevertheless, as highlighted by the examples of female Lepidoptera, which by and large utilize alcohols, acetates, aldehydes, and hydrocarbons, including epoxyhydrocarbons, pheromones are restricted to some groups of chemicals with marked structural similarities. Even in the Coleoptera, with more diversity in molecular structures, structurally related compounds are used by insects of the same family as evidenced by the scarab beetles; the sex pheromones of Popillia japonica, Anomala rufocuprea, and A. cuprea are (R,Z)-5-( )-(dec1 -enyl)oxacyclopentan-2-one [1], methyl (Z)-tetradec-5enoate [2] and (R,Z)-5-(-)-(oct-l-enyl) oxacyclopentan-2-one [3], respectively. On the other hand, Costelytra zealandica and Kheper lamarcki of the same family have been reported to utilize quite different chemicals, viz., phenol [4] and a mixture of hexadecanoic acid, 2,6-dimethyl-5-heptenoic acid, and (E)-nerolidol along with a polypeptide pheromone carrier [5], respectively. We report here that the large black chafer Holotrichia parallela (Mots.) (Coleoptera: Scarabaeidae), ookurokogane in Japanese, utilizes a unique sex pheromone, L-isoleucine methyl ester. H. parallela is an important agricultural pest in Japan, which was initially called Lachnosterna morosa Waterhouse [6] and later renamed [7].

(Z)-11-Pentacosene is the major sex pheromone component inDrosophila virilis (Diptera)

SummaryA crude cuticular extract from 3450 virgin 9–13 day old female fruit flies(Drosophila virilis), was subjected to chromatography accompanied by bioassay for sex pheromone activity. After three chromatographic steps, fractions containing active monoenes and dienes were obtained. Chemical analysis by infrared absorption, gas liquid chromatography and gas chromatography/mass spectrometry of the active fraction indicated that active monoenes were comprised chiefly of (Z)-11-pentacosene (abbreviated (Z)-11-C25:1), (Z)-13-C27:1’, (Z)-13- and (Z)-14-C29:1. Synthetic monoenes were made, and only (Z)-11-C25:1 elicited good courtship behaviour in maleD. virilis. Therefore it was concluded that (Z)-11-C25:1 was a major sex pheromone. A total of 16.2±1.32 µg of cuticular hydrocarbons was isolated from 10 day old females, including 5.9±0.56 µg of (Z)-11-C25:1. An additive effect was suggested from the higher observed courtship response when using a mixture of active dienes with the active monoene.

Inhibition of male response of drugstore beetles to stegobinone by its isomer.

Stegobinone, (2S, 3R, 1′R)-2,3,-dihy dro-2,3,5-trimethyl-6-(1′-methyl-2′-oxobutyl)-4H-pyran-4-one, the sex pheromone of drugstore beetles (Stegobium paniceum L.), elicited the pheromonal response from the males of the species in our bioassay system; however, the synthesized diastereomeric mixture of this compound was actually inactive to the males. Although the stegobinone isolated from the beetles of this species had significant activity, its enantiomeric [(±)-2S,3R,1′S-] and diatereomeric [(±)-2S,3S,1′RS-] isomers were inactive. Adding the (±)-2S,3R,1′S isomer to stegobinone significantly reduced the male response. Furthermore, the activity of Stegobinone vanished on keeping it at room temperature for two weeks. In such a stored stegobinone sample, the presence of 2S,3R,1′S isomer, the inhibitory component, was confirmed. This isomer might be produced by C-1′ epimerization during storage.

Antifungal activity of Caloglyphus polyphyllae sex pheromone and other mite exudates

The relation between mites and fungi, which share stored-product habitats, is conflicting in the literature. Mites are reported to feed on fungi, heavily inoculate clean grain with spores o f these fungi and later feed to a considerable extent upon the fungi that developed [2]. Some species feed and multiply on a wide variety of fungal cultures, whilst others only flourish on a few species [3]. On the other hand, the inhibition of fungus development on Acarus siro culture is assumed to be due to the secretion of an antifungal substance [4]. Citral, which is used by various astigmatid mites as an alarm pheromone [5] and is fungitoxic comparable to amphotericin B [6], was assigned as the mold inhibitor of Carpoglyphus lactis and Lardoglyphus konoi [7]. We report here that the stored-product mite exudates c~and /3-acaridial the sex pheromone of Caloglyphus polyphyllae are potent antifungal substances, tens of times more active than citral. Four components of mite secretion, namely, neral, farnesal, orand/3-acaridial were examined for their fungitoxic activity. In a preliminary screening, neral and citral (neral + geranial, 1 :1) showed the same results and thus the former was used in the tests. Citral from astigmatid mites is made up mainly of neral, except for Dermatophagoides pteronyssinus [8].

Robinal, a highly conjugated monoterpenoid from the mite Rhizoglyphus robini. Chemical ecology of astigmatid mites, XXVII (1).

for only 2 °7o at most of the ipsenol in feeding males [6]. The absence of myrcene in digger pine phloem makes it unlikely that this compound could serve as a precursor. Allowing that a trace of myrcene was present in the oleoresin of digger pine (at most 0.01 #g//zl, our quantification limit), and assuming very conservatively that this was converted completely to the components and no components were released, a beetle would need to eat at least 80/zl or eight times its weight in oleoresin, and even higher amounts to account for releases of pheromone during the feeding period. This appears to be virtually impossible since the males guts were observed to contain phloem, and oleoresin is toxic to bark beetles (L paraconfusus and Dendroctonus brevicomis) [6, 14]. From our results it is apparent that all five pine species are about equally suitable as hosts, at least in terms of adult survival, nuptial chamber construction, pheromone production, and attraction. The production of similar amounts of ipsenol and ipsdienol in all pine species regardless of myrcene titer, as well as the inadequate supply of myrcene in digger pine, indicate that males may utilize precursors other than myrcene predominantly. This implies that insect-plant coevolution of host tree selection and resistance cannot be affected by variation of myrcene in the tree.

Parasitic wasp, Dinarmus basalis, utilizes oviposition-marking pheromone of host azuki bean weevils as host-recognizing kairomone

A host-recognizing kairomone responsible for the stinging behavior of the parasitic wasp, Dinarmus basalis, was studied. Fresh azuki beans coated with an acetone extract of the azuki beans, from which both emerged wasps and their host weevils were removed, elicited stinging behavior from female wasps. The kairomone is a mixture of saturated hydrocarbons and diacylglycerols, both of which are required for activity. The kairomone is composed of normal and methyl-branched hydrocarbons with carbon numbers ranging from 25 to 35, most of which are known as the hydrocarbon constituents of an oviposition-marking pheromone of the host azuki bean weevils, Callosobruchus chinensis. This indicates that D. basalis utilizes the oviposition-marking pheromone of its host weevils as a host-recognizing kairomone.

Syntheses of Alarm Pheromone Analogues of the Mold Mite, Tyrophagus putrescentiae, and Their Biological Activities

Against the mold mite, Tyrophagus putrescentiae, 3,7-dimethyl-(Z)-2-octenyl formate (II) is the most active compound as an alarm pheromone besides the natural pheromone, neryl formate (I), and this activity is equal to I (1-10 ppm). In order to elucidate the structural requisites for inducing alarm pheromone activity, a total of 16 analogues of I were prepared by modifying the structure of II. For preparation of 3-methyl- and 3-ethyl-(Z)-2-alkenyl formates, the Wittig reaction of ethoxy- or methoxy-carbonylmethylene triphenyl phosphorane with 2-alkanone or 3-alkanone was used. The reaction with 2-alkanone gave a mixture of (Z)-2-alkenoate (ca. 40%) and (E)-2-alkenoate (ca. 60%) in an average 60% yield. The reaction with 3-alkanone gave a mixture of (Z)-2-alkenoate (56%) and (E)-2-alkenonate (44%).Alarm pheromone activities were demonstrated on 14 compounds of (Z)-2-alkenyl formates. The presence of the (Z)-allylic primary alcohol formate moiety in a molecule was clarified as the key to induce pheromone ac...

ALARM AND AGGREGATION PHEROMONES OF MITES

Abstract The mold mite Tyrophagus putrescentiae (Schrank) was used as an assaying mite in order to investigate the structural requisites of neryl formate for inducing alarm pheromone activity. There was found to be no need to preserve the acyclic monoterpenoid structure for the development of biological activity, and the basic requisite for the activity was the presence of a (Z)-allylic primary alcohol formate within an n -octane or n -nonane carbon skeleton. The composition of the citral when emitted by the citral producing mites is neral; however, during the solvent extraction process, a part of neral is isomerized to geranial. This reaction was catalyzed by the mites bodies, and part of the citral was further reduced to geraniol and nerol. Several carbonyl compounds were also reduced to the corresponding alcohols. Strong attraction and aggregation behavior of test mites to the extracts of Lardoglyphus konoi was noted during bioassay of the alarm pheromone. The active principle isolated as the aggregation pheromone was active not only con-species but also with other related mites. The structure of the pheromone was identified as 1,3,5,7-tetramethyldecyl formate by physicochemical measurements and chemical degradation. The synthesized diastereomeric mixture of racemates had one-tenth the activity of the natural pheromone. The absolute configuration of C 1 was found to be R. The pheromone has been assigned the trivial name lardolure.