H. J. Bestmann

A new pheromone of the silkworm moth Bombyx mori

The female silkmoth Bombyx mori L. emits a second pheromone component bombykal (E-10, Z-12-hexade-cadien-1-al) in addition to the well-known sexual attractant bombykol (E-10, Z-12-hexadecadien-1-ol). Bombykal stimulates its own specialized and highly sensitive olfactory cells of the male moth. Surprisingly, the aldehyde inhibits the release of the males wing-fluttering response to bombykol.

Sulphur-containing "perfumes" attract flower-visiting bats.

Abstract We tested the attractiveness of individual scent compounds of bat-pollinated flowers to their pollinators, small flower-visiting bats of the genus Glossophaga (Phyllostomidae). Twenty compounds belonging to four different chemical substance classes were tested, both in the laboratory and in the field. In the laboratory, the bats (Glossophaga soricina) approached odour sources spontaneously and without preceding experience. Without ever receiving any reward they preferred the scent of a sulphur-containing compound, dimethyl disulphide, to several other odour components emitted by bat-pollinated flowers, and to scentless controls. In the field, at La Selva station in the tropical lowland rain forest of Costa Rica, G. commissarisi were attracted by two sulphur-containing compounds, dimethyl disulphide and 2,4-dithiapentane, to visit artificial flowers filled with sugar water. Thus, in nectarivorous bats the sense of smell obviously plays an important role in searching for and localising food sources, and even single components of the scent bouquets of bat-pollinated flowers are attractive. The preference for sulphur-containing odours seems to be innate.

Number and sensitivity of three types of pheromone receptor cells inAntheraea pernyi andA. polyphemus

SummaryThree types of receptor cells responding respectively to the pheromone components (E,Z)-6,11-hexadecadienyl acetate (AC1, (E,Z)-6,11-hexadecadienal (AL) and (E,Z)-4,9-tetradecadienyl acetate (AC2) occur in different combinations in the sensilla trichodea on male antennae ofAntheraea polyphemus andA. pernyi. The numbers of cells sensitive to AC1 and AL and the average sensitivities of these cells are about equal, and higher than those of the AC2-cells. The cells sensitive to AC2 are relatively common in the small hairs positioned on the anterior side of the antenna. The product of three experimental values — (i) the relative number of each cell type, (ii) the average relative sensitivity of the cells and (iii) the estimated relative release rate of the respective pheromone component from the female gland — suggest that the distance from the female over which a compound can be detected or, the potential active space, is different for each pheromone component.

Cuticular compounds of workers and queens in two Leptothorax ant species — a comparison of results obtained by solvent extraction, solid sampling, and SPME

SummaryWe investigated cuticular hydrocarbons and fatty acids of workers and queens from two ant species, Leptothorax acervorum and L. gredleri. Cuticular compounds were extracted from single ants by solvent extraction, solid sampling, and solid phase microextraction (SPME) with two different polydimethylsiloxane (PDMS) fibers and analyzed using GC and GC-MS. All three methods gave similar results, documenting that SPME can be applied to very small, live ants (body size appr. 3 mm). The hydrocarbon mixtures consisted mostly of branched and unbranched alkanes and alkenes within the range of C25 to C33. Dufour glands of both species contained a blend of hydrocarbons different from those found on the cuticle. In addition, terpenoids, especially tetramorenes were present in the Dufour gland contents. In a principal components analysis based on the relative proportions of cuticular compounds, most nestmate workers clustered in four groups corresponding to the original four investigated colonies. Queens and workers differed significantly in their chemical profiles, suggesting that the two castes bear specific labels.

Technique for injecting intact glands for analysis of sex pheromones of Lepidoptera by capillary gas chromatography : Reinvestigation of pheromone complex ofMamestra brassicae.

The structure elucidation of sex pheromones of Lepidoptera by a solid-sample injection technique in conjunction with capillary gas chromatography is described. The applicability of this method in GC and GC-MS modes was demonstrated by reanalyzing the sex attractants of females ofOstrinia nubilalis andBombyx mori. The pheromone complex ofMamestra brassicae was reinvestigated and (Z)-9-hexadecenyl acetate and (Z)-11-hexadecenol were found in addition to already known pheromone components of this species. By using the solid-sample injection, the exact site of pheromone release could be determined inM. brassicae.

Chemical composition and function of metapleural gland secretion of the ant,Crematogaster deformis smith (hymenoptera: Myrmicinae)

The secretion of the hypertrophied metapleural gland of the antCrematogaster deformis contains a mixture of phenols, consisting mainly of 3-propylphenol, 3-pentylphenol, 3,4-dihydro-8-hydroxy-3-methylisocoumarin (mellein), 5-propylresorcinol, and 5-pentylresorcinol. The secretion is released, as a repellent, when the highly vulnerable petiolar-postpetiolar region of the abdomen is attacked by enemy ants. In addition, small amounts of the secretion are released regularly to serve as an antiseptic, which is considered the original function of the gland. The secretion also has some insecticidal properties.

Regulatory steps in sex pheromone biosynthesis inMamestra brassicae L. (Lepidoptera: Noctuidae)

The de novo biosynthesis of (Z)-11-hexadecenyl acetate, the most abundant pheromone component inM. brassicae, starting from acetate via palmitic acid, requires the presence of a pheromone-biosynthesis-activating neurohormone. Moreover, the conversion of palmitic acid to (Z)-11-hexadecenyl acetate is strongly dependent on the presence of the neurohormone. However, no significant dependence was found for the conversion of (Z)-11-hexadecenoic acid to (Z)-11-hexadecenyl acetate. This indicates that the neurohormonal control of pheromone biosynthesis inM. brassicae occurs at the level of palmitic acid.

All-trans geranylgeranyl acetate and geranylgeraniol, recruitment pheromone components in the dufour gland of the ponerine antEctatomma ruidum Pheromones, 100 [1]

Theodor Boveri Institut, Lehrstuhl ftir Verhaltensphysiologie und Soziobiologie der Universit~it, D-97074 Wtirzburg, Germany one major peak and a few minor peaks (Fig. 1). The mass spectrum of the major component 1 (approx. 140 ng per gland) is shown in Fig. 2. This spectrum is similar to that of the diterpene geranylgeraniol [8]. Retention time and molecular ion (M + 332) suggested that 1 represents the corresponding acetate. Investigating the minor compounds, we also found geranylgeraniol (2). In contrast to /, 2 occurs only in traces (1 10 pg) in the Dufours gland of E. ruidum. By micropreparative gas chromatography [9] on a 2 m × 4 mm glass column SE 52, different fractions of the E. ruidum Dufours gland extract were split, trapped, and tested by a bioassay, following the procedures described in [4]. Only the fraction collected between the retention times of heneicosane (RI 2100, 32.79 min) and

Mellein, a Trail Pheromone Component of the Ant Lasius fuliginosus

Abstract3,4-Dihydro-8-hydroxy-3-methylisocoumarin (mellein) and 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one are among the volatile constituents identified from the hindgut of the formicine ant Lasius (Dendrolasius) fuliginosus Mellein induces trail-following behavior in worker ants of this species and evokes electrophysiological responses from their antennae. The trail-following activity released by (R)-(−)-mellein is significantly higher than that elicited by its (S)-(+) antipode, or the racemic mixture. The above-mentioned pyranone is found also in the honeydew of aphids, the customary diet of this ant species. The pyranone also evokes some trail-following behavior, but its activity is far less pronounced than that of mellein. Apparently, extra pheromone components are present in the hindgut, since the activity of these two constituents, either individually or as a mixture, does not completely account for the total activity released by a hindgut extract containing similar amounts of these two compounds.

Pheromone XII. Männchenduftsoffe von Noctuiden (Lepidoptera)

By gaschromatographic-mass spectrometric methods 2-phenylethyl alcohol, benzylalcohol, phenylacetaldehyde and benzaldehyde were identified from scent brushes of male Noctuidae species (Lepidoptera).By gaschromatographic-mass spectrometric methods 2-phenylethyl alcohol, benzylalcohol, phenylacetaldehyde and benzaldehyde were identified from scent brushes of male Noctuidae species (Lepidoptera).