Odile Bonnard

Isolation and identification of (3Z,6Z,8E)-3,6,8-Dodecatrien-1-ol in Reticulitermes santonensis Feytaud (Isoptera, Rhinotermitidae): Roles in worker trail-following and in alate sex-attraction behavior

Abstract (3Z,6Z,8E)-3,6,8-Dodecatrien-1-ol was isolated and identified by gas chromatography-mass spectrometry in workers and alates of Reticulitermes santonensis Feytaud (Isoptera, Rhinotermitidae). This unsaturated alcohol is about 10 times more abundant in alates than in workers. Synthetic (3Z,6Z,8E)-3,6,8-dodecatrien-1-ol is highly active in eliciting trail-following in workers, and the threshold concentration is about 0.1 pg/cm trail. In alates, it elicits trail-following in both sexes at low concentration and sex attraction in male alates at high concentrations. It is suggested that (3Z,6Z,8E)-3,6,8-dodecatrien-1-ol is the main component of the trail-following pheromone as well as the sex pheromone in Reticulitermes santonensis .

CHEMISTRY OF DEFENSIVE SECRETIONS IN NYMPHS AND ADULTS OF FIRE BUG, Pyrrhocoris apterus L. (HETEROPTERA, PYRRHOCORIDAE)

The defensive secretions from the nymphs and the adults of both sexes inP. apterus were chemically investigated. Forty components were identified from the nymphal posterior dorsoabdominal glands and 35 from the adult metathoracic glands of both sexes. Within the 43 identified chemicals, we found 23 aldehydes, five saturated hydrocarbons, five alcohols, three ketones, three lactones, two terpenes, one phenol and one ester. Thirteen of these compounds had never been reported within the Heteroptera. Whereas eight components are specific to the nymphs, methyl pentenal, (E)-2-hexenol, and heptadecanal are the only adult-specific components. The biological role of all the identified chemicals is almost unknown inP. apterus and is discussed comparatively with regard to other Heteroptera.

2-Methylthiazolidine and 4-ethylguaiacol, male sex pheromone components of the cockroachNauphoeta cinerea (dictyoptera, blaberidae): A reinvestigation

InNauphoeta cinerea, male calling behavior is associated with sex pheromone release by the sternal glands. The male pheromone that attracts females from a distance is a mixture of 2-methylthiazolidine and 4-ethylguaiacol. It is active at very low concentrations, 0.05 and 0.01 ng, respectively. Two other compounds, 3-hydroxy-2-butanone and 2-methyl-2thiazoline, act at close range, keeping the female in the vicinity of the male. The function of the volatile pheromone and those of previously described contact pheromones are discussed in regard to their possible involvement in the establishment of male dominant-subordinate relationships.

(Z)-dodec-3-en-1-ol, a novel termite trail pheromone identified after solid phase microextraction from Macrotermes annandalei.

(Z)-dodec-3-en-1-ol was isolated and identified by GC-MS as the major component of the trail-following pheromone from whole body and sternal gland extracts of workers of the fungus-growing termite, Macrotermes annandalei (Silvestri) (Termitidae, Macrotermitinae). For the first time, this trail pheromone was also identified by using solid phase microextraction from the surface of the secretory sternal gland of workers. Bioassays showed that synthetic dodecenol induced both orientation and recruitment behavioral effects. The activity threshold of (Z)-dodec-3-en-1-ol in eliciting trail-following is similar to that of (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol in the Rhinotermitidae, but amounts of dodecenol secreted are 100 times higher than those of dodecatrienol. There is about 1 ng of (Z)-dodec-3-en-1-ol per worker. Artificial trails made of synthetic dodecenol are able to compete with natural trails in the field. The activity duration of synthetic (Z)-dodec-3-en-1-ol trails is shorter than that of trails made from whole sternal secretion of workers. Observations showed that (Z)-dodec-3-en-1-ol is probably the only major component of the trail-following pheromone of M. annandalei and that it could be associated with other compounds in a pheromonal blend providing specificity and/or stability to trails.

(Z,Z,E)-3,6,8-Dodecatrien-1-ol, A Major Component of Trail-Following Pheromone in Two Sympatric Termite Species Reticulitermes lucifugus grassei and R. santonensis

Trail-following bioassays show that trails of the two subterranean termites, Reticulitermes lucifugus grassei and R. santonensis, which are sympatric in some areas of southwestern France, are not species specific. Even when tested just above threshold level, trails from pentane extracts of whole workers of R. santonensis are always preferred by both species. If the R. santonensis extract is progressively diluted, the preference is lost. In purified extracts of workers of R. lucifugus grassei that elicited a trail-following response, only one compound is active. It was identified by GC-MS as the same major compound of the trail-following pheromone of R. santonensis: (Z,Z,E)-3,6,8-dodecatrien-1-ol (DTE-OH). The threshold concentration of activity of synthetic DTE-OH was determined to be 10−3 ng/cm of trail; optimal activity was obtained at 10−2 ng/cm of trail. The increase of trail-following activity of worker extracts of R. lucifugus grassei after hydrolysis by potassium hydroxide suggests that DTE-OH also is bound to other components in sternal gland secretions. DTE-OH was also identified in alates of R. lucifugus grassei, suggesting that the compound functions both as a trail-following and a sex pheromone, as has been shown to be the case in R. santonensis. This demonstrates the high economy developed by termites in their strategies of chemical communication.

(+)-α-Pinene in the defensive secretion of Nasutitermes princeps (Isoptera, Termitidae)

The frontal secretion ofNasutitermes princeps consists of 89% diterpenes and 11% monoterpenes. In the samples studied, (+)-α-pinene, whose optical purity reaches 99.5%, accounts for more than 80% of the monoterpenic content.

(3Z,6Z,8E)-3,6,8-Dodecatrien-1-ol: Sex pheromone in a higher fungus-growing termite,Pseudacanthotermes spiniger (Isoptera, macrotermitinae).

The female sex pheromone of the fungus-growing termitePseudacanthotermes spiniger (Termitidae, Macrotermitinae) was isolated from sternal glands of alates. The compound inducing attraction and excitation in males was identified as the (3Z,6Z,8E)-3,6,8-dodecatrien-1-ol by GC-MS, microhydrogenation, GC-FTIR, and NMR. This unsaturated alcohol is present in both sexes but in much higher quantities in females than in males (about 10 times). The hypothesis is suggested that this alcohol, which is detected at extremely low concentrations by the workers ofP. spiniger, may be used either as a trail-following pheromone or a sex pheromone according to concentrations and to target castes. The presence of this alcohol in Macrotermitinae reinforces the idea of a phylogenetic proximity between this subfamily of higher termites and the lower termites Rhinotermitidae, where the unsaturated alcohol was previously found. The sternal glands of alates ofP. spiniger also contain a geometric isomer of (3Z,6Z,8E)-3,6,8-dodecatrien-1-ol.

Calling behaviour of female Periplaneta americana: Behavioural analysis and identification of the pheromone source

Abstract The site for the production of Periplanone B, one of the components of the female sex pheromone of Periplaneta americana , was localized in glands situated in the genital atrium, and we have called these structures atrial glands. While emitting the sex pheromone, females adopt a characteristic calling posture during which time the atrial glands are exposed. Behavioural assays of males utilizing pentane extracts of various female body parts revealed that atrial gland extracts are highly attractive, and induced more wing-raising behaviour, than any other female body part. GC-MS analyses support these results by revealing that Periplanone B is only present in the atrial glands. We estimate that about 30 ng of Periplanone B are present in the glands.

The monoterpenoid fraction of the defensive secretion in Nasutitermitinae from Papua New Guinea

Abstract The composition of the monoterpenoid fraction of the defensive frontal secretion is elucidated in eight Nasutitermitinae species, namely: Grallatotermes grallator, Nasutitermes gracilirostris, N. novarumhebridarum, N. polygynus, N. princeps, N. rufirostris and two undescribed Nasutiterrnes . Each species possesses a characteristic blend of rnonoterpenes. α Pinene predominates in the secretion of four species from these. The other important monoterpenes are β-pinene, limonene and myrcene. Sabinene is present in the secretion of G. grallator, N. gracilirostris, N. princeps and one species from the undescribed Nasutitermes . It is the first time that sabinene is detected in Nasutitaermes and Grallototermes frontal secretion. Another monoterpene undescribed in Nasutitermitinae defensive secretion was identified in N . sp. F as ( R )-cyclohexene, l -methyl-5-(1-methylethenyl).

Sesquiterpenes in the frontal gland secretions of nasute soldier termites from New Guinea

In five New GuineaNasutitermes (N. gracilirostris, N. novarumhebridarum, N. torresi, N. triodiae, and an undescribed speciesN. sp.F), we have detected and identified 10 sesquiterpenes. Eight of these compounds (β)-elemene,β-caryophyllene,α-humulene,α-muurolene,γ-selinene,β-selinene, germacrene-A, and γ2-cadinene) were identified by GC and GC-MS (EI). Two uncommon sesquiterpenes, (5R*, 7R*, 10S*)-selina-4(14),11-diene and (5R*, 7R*, 10S*)-selina-3,11-diene, were identified by GC, GC-MS (EI, CI), GC-FTIR, and mono- and bidimensional NMR. Whereas in most species sesquiterpenes are present in low or trace amounts, inN. novarumhebridarum the sesquiterpenic fraction of soldier frontal gland secretion is equal to that of the monoterpenes.