Blanka Kalinová

Comparison of Age-dependent Quantitative Changes in the Male Labial Gland Secretion of Bombus Terrestris and Bombus Lucorum

Age-related changes of antennal-active components of male labial gland extracts were studied in two closely related bumblebee species, Bombus terrestris and B. lucorum. In B. terrestris, compounds eliciting electroantennogram (EAG) responses of virgin queens were ethyl dodecanoate, 2,3-dihydrofarnesal, 2,3-dihydrofarnesol, hexadecan-1-ol, octadeca-9,12,15-trien-1-ol, and geranylcitronellol. Compounds that elicited EAG responses from queens of B. lucorum were ethyl dodecanoate, ethyl tetradec-7-enoate, ethyl tetradec-9-enoate, ethyl hexadec-9-enoate, hexadecan-1-ol, hexadec-7-enal, octadeca-9,12-dien-1-ol, octadeca-9,12,15-trien-1-ol, and octadecan-1-ol. Quantities of these compounds in the labial glands changed significantly over the lifetime of the respective males of the two species. In both species, concentrations of the respective compounds reached their maximum within seven days after eclosion. Subsequently, a rapid decrease in the amount of EAG-active compounds occurred in B. terrestris, whereas in B. lucorum the amount of active compounds stayed approximately constant or decreased at a slow rate. Microscopy showed that in B. terrestris secretory cells of the labial glands undergo apoptosis from the fifth to the tenth day of life, whilst in B. lucorum labial gland cells remain unchanged throughout the life of the males.

Can chemical cues from blossom buds influence cultivar preference in the apple blossom weevil (Anthonomus pomorum)

The post‐hibernating adults of the apple blossom weevil, Anthonomus pomorum (L.), show preferences for certain cultivars in mixed apple tree orchards. The degree of infestation of various cultivars was positively correlated with the density of flower buds at a comparable phenological stage, but the numbers of collected beetles were not linearly proportional to the bud density of different cultivars. Hence other possible factors, namely chemical ones, were investigated. Chromatographic analysis of apple tree bud emanations showed that volatiles from two different apple cultivars that show a different attractiveness to the beetles, differed in chemical composition. Several less volatile components of the bud emanation bouquet elicited antennographic responses in both male and female antennae. Four terpene hydrocarbons, namely 3‐carene, perillene, caryophyllene and (E,E)‐α‐farnesene, were identified among the components that produced distinct electrophysiological responses in the antennae. These findings support a hypothesis that the adult weevils use chemical cues for olfactory discrimination during host‐searching behaviour.

Stereochemistry of lepidopteran sex pheromone biosynthesis: a comparison of fatty acid CoA Delta 11-(Z)-desaturases in Bombyx mori and Manduca sexta female moths

Abstract The absolute stereochemistry of fatty acid (FA) desaturation in Bombyx mori and Manduca sexta female pheromone glands (PGs), catalysed by FA-CoA Δ11-( Z )-desaturases, was determined using chiral, specifically labelled palmitic acids {[2,2,3,4,5,5,6,6,7,8,9,9,11,12− 2 H 14 ]–(11 R ,12 S )− 1 and [2,2,3,4,5,5,6,6,7,8,9,9,11,12− 2 H 14 ]–(11 S ,12 R )−1)} as metabolic probes. The (11 R ,12 S )− 1 acid was converted in PGs of treated virgin females to labelled methyl (11 Z )-hexadecenoate ([ 2 H 14 ]− 2 , Mw=282 Da). In incubations with the opposite enantiomer two deuterium atoms from (11 S ,12 R )− 1 were removed, yielding [ 2 H 12 ]− 2 of Mw=280 Da. These results were confirmed by methylthiolation of [ 2 H 14 ]− 2 and [ 2 H 12 ]− 2 with a dimethyl disulfide/iodine mixture. Mass spectra of the DMDS adducts directly showed the distribution of deuterium atoms in the labelled methyl esters of 2 . The data consistently indicate, that the studied insects possess Δ11-( Z )-desaturases with pro -( R ) C(11)-H and pro -( R ) C(12)-H stereospecificity, catalysing a syn -elimination of two hydrogen atoms.

Cockroaches as Pollinators of Clusia aff. sellowiana (Clusiaceae) on Inselbergs in French Guiana

BACKGROUND AND AIMS A report is made on a new species of Clusia related to C. sellowiana that dominates the vegetation of the Nouragues inselberg in French Guiana. The focus is on the pollination biology and on the remarkable relationship of this plant species to Amazonina platystylata, its cockroach pollinator. This appears to be only the second record of pollination by cockroaches. METHODS Pollination ecology was investigated by combining morphological studies, field observations and additional experiments. Floral scent was analysed by gas chromatography-mass spectrometry. The role of acetoin, the major component of the scent of this species of Clusia, in attracting pollinators was examined in field attraction experiments. The ability of cockroaches to perceive acetoin was investigated by electroantennography (EAG). KEY RESULTS The Clusia species studied produces seeds only sexually. Its nocturnal flowers are visited by crickets, ants, moths and cockroaches. A species of cockroach, Amazonina platystylata, is the principal pollinator. The reward for the visit is a liquid secretion produced by tissues at the floral apex and at the base of the ovary. Although the cockroaches have no structures specialized for pollen collection, their body surface is rough enough to retain pollen grains. The cockroaches show significant EAG reactions to floral volatiles and acetoin, suggesting that the floral scent is a factor involved in attracting the cockroaches to the flowers. CONCLUSIONS The results suggest that the plant-cockroach interaction may be quite specialized and the plant has probably evolved a specific strategy to attract and reward its cockroach pollinators. Acetoin is a substance involved in the chemical communication of several other cockroach species and it seems plausible that the plant exploits the sensitivity of cockroaches to this compound to attract them to the flowers as part of the pollination syndrome of this species.

Pheromone Analyses of the Anastrepha fraterculus (Diptera: Tephritidae) Cryptic Species Complex

ABSTRACT The South American fruit fly Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) cryptic species complex is presently one of the most studied pest models in terms of speciation and population mating compatibility. The improvement of pest-control techniques has strongly relied on successful implementation of laboratory strains into wild populations. Pheromone communication plays an important role in the mating process in the South American fruit fly. Therefore, the main goal of the present study was to investigate the pheromone composition of 7 different populations, originating from geographically distant locations in Brazil and Argentina. Fourteen volatile compounds were identified in calling male emanations by GC×GC/TOF-MS and the data obtained were subsequently analyzed by multivariate statistics. The pheromone composition varied both quantitatively and qualitatively among the studied populations. These results will serve as the basis for further electrophysiological analyses.

GC × GC/TOF MS technique—A new tool in identification of insect pheromones: Analysis of the persimmon bark borer sex pheromone gland

Conventional gas chromatography with electroantennographic detection (GC-EAD) and two-dimensional (GCxGC) gas chromatography using a time-of-flight mass spectrometric detector (TOFMS), were combined to analyse the female sex pheromone gland extract of the persimmon bark borer, Euzophera batangensis. GC-EAD analysis produced two EAD responses in GC areas where no compounds were detected by FID detection. GCxGC/TOFMS analysis of this area indicated the presence of several chemicals, including (Z9,E12)-tetradeca-9,12-dien-1-ol and (Z9)-tetradec-9-en-1-ol, pheromone components of closely related Euzophera species. Spectral characteristics, retention behaviour and the ability to elicit GC-EAD responses imply that both identified unsaturated alcohols are candidates for E. batangensis sex pheromone components. GCxGC/TOFMS facilitated the analysis of complex matrices on a subnanogram level and was shown to have great potential as a powerful tool in the analysis of insect pheromones.

An integrative approach to unravel the Ceratitis FAR (Diptera, Tephritidae) cryptic species complex: a review

Abstract This paper reviews all information gathered from different disciplines and studies to resolve the species status within the Ceratitis FAR (Ceratitis fasciventris, Ceratitis anonae, Ceratitis rosa) complex, a group of polyphagous fruit fly pest species (Diptera, Tephritidae) from Africa. It includes information on larval and adult morphology, wing morphometrics, cuticular hydrocarbons, pheromones, microsatellites, developmental physiology and geographic distribution. The general consensus is that the FAR complex comprises Ceratitis anonae, two species within Ceratitis rosa (so-called R1 and R2) and two putatitve species under Ceratitis fasciventris. The information regarding the latter is, however, too limited to draw final conclusions on specific status. Evidence for this recognition is discussed with reference to publications providing further details.

Identification by GC-EAD of the two-component trail-following pheromone of Prorhinotermes simplex (Isoptera, Rhinotermitidae, Prorhinotermitinae)

GC/MS analysis confirmed that neocembrene is the major component of the trail pheromone in the three species of the termite genus Prorhinotermes (P. simplex, P. canalifrons, P. inopinatus). In addition, EAG and GC-EAD experiments with P. simplex strongly suggest that dodecatrienol is a quantitatively minor component but a qualitatively important component of this trail pheromone. Trail-following bioassays confirmed the two-component nature of the trail pheromone. This is the first report of the use of the GC-EAD for the identification of trail pheromone in termites. These original results underline once again the special phylogenetic status of the Prorhinotermitinae among Rhinotermitidae.

Male bumble bee pheromonal components in the scent of deceit pollinated orchids; unrecognized pollinator cues?

The pollination of the non-rewarding Orchis pauciflora was studied. The most abundant visitors of O. pauciflora were B. terrestris queens. The fragrance of O. pauciflora inflorescence was dominated by a sesquiterpene (E)-β-farnesene. (E,E)-α-Farnesene, (E)-2,3-dihydrofarnesol, geranylcitronellol, and the monoterpenes limonene and 1,8-cineol were found among less abundant constituents. The sesqui- and diterpenes detected in O. pauciflora fragrance are frequent constituents of male marking pheromones of many bumble bee species. Enantioselective analysis of O. pauciflora scent and B. terrestris male marking pheromone revealed the presence of the (S)-isomer of (E)-2,3-dihydrofarnesol in both samples, and electrophysiological experiments showed that mainly the (S)-isomer activated the antennal receptors. In field experiments, O. pauciflora inflorescences were enriched with the main compound (E)-β-farnesene resulting in significantly increased pollinia export. We here discuss the chemical similarities between orchid and bumble bees and whether the presence of bumble bee male pheromone components in O. pauciflora fragrance increases its fitness.

Sex Pheromone of Horse-Chestnut Leafminer Cameraria ohridella and Its Use in a Pheromone-Based Monitoring System

Gas chromatography combined with electroantennographic detection (GC-EAD), electroantennography (EAG), and wind-tunnel and field experiments were used to reinvestigate the composition of Cameraria ohridella (Lepidoptera, Gracillariidae, Lithocolletinae) sex pheromone. The GC-EAD experiments showed one EAD-active area corresponding to the major pheromone component, (8E,10Z)-tetradeca-8,10-dienal. The EAG experiments proved that (9E)-tetracedecenal and stereoisomers of (8E,10Z)-tetradeca-8,10-dienal exhibited significant electrophysiological activity and could, therefore, be considered as possible minor pheromone components. However, wind-tunnel and field experiments demonstrated that none of these compounds affect the efficacy of the main pheromone component. A monitoring system based on (8E,10Z)-tetradeca-8,10-dienal was developed and used to study the flight activity of C. ohridella.