Wittko Francke

Hamburg University | UHH · Institute of Organic Chemistry

The cypress bark beetle, Phloeosinus aubei, is of increasing concern in the European market of scale-leafed conifers. Neither the reproductive behaviour nor the chemical ecology have been studied in detail so far, and no specific attractant traps are available to monitor the flight of adults. We established that stridulation by males is crucial for...

The cypress bark beetle, Phloeosinus aubei Perris (Coleoptera: Curculionidae, Scolytinae), is of increased concern in the European market of scale-leafed conifers (Cupressaceae). Surprisingly, its chemical communication has only scarcely been studied and no specific trap-based monitoring system is available for detection of flight of the adults. In...

The cypress bark beetle, Phloeosinus aubei Perris (Coleoptera: Curculionidae, Scolytinae), is of increased concern in the market of scale-leafed conifers (Cupressaceae), across a wide range of its expansion area in Europe. Surprisingly, its pheromonal communication has only scarcely been studied no specific trap-based monitoring system is available...

With approximately 83,000 species described, Curculionidae is the largest family of beetles, comprising more than 80% of all weevil species worldwide. Many species of Curculionidae attack a wide range of native and orchards crops, as well as globally important stored products such as grains, flour, and seeds, being responsible for significant envir...

The obligate pollination mutualism between Yucca and yucca moths is a classical example of coevolution. Oviposition and active pollination by female yucca moths occur at night when Yucca flowers are open and strongly scented. Thus, floral volatiles have been suggested as key sensory signals attracting yucca moths to their host plants, but no bioact...

Deception of floral visitors in pollination systems is widely distributed among flowering plants. In deceptive systems, the flower (or part of it) or inflorescence mimics either a specific or an unspecific model to attract pollinators. A previous study showed that Telipogon peruvianus flowers developed sexual deception for pollination. However, it...

The hydrocarbon pattern in the floral scent of Yucca species was found to comprise a group of unbranched, mid-chain alkanes, alkenes, and an alkadiene. In Y. reverchonii, highly dominant (Z)-8-heptadecene is accompanied by (6Z,9Z)-6,9-heptadecadiene and heptadecane as minor components and by traces of other saturated and unsaturated hydrocarbons wi...

(Z,Z)-Octadeca-10,12-dienoic acid was synthesised by coupling (Z)-1-bromohept-1-ene with protected undec-10-yne-1-ol. Stereoselective hydrogenation of the triple bond of the obtained enyne-system followed by deprotection yielded (Z,ZZ)-octadeca-10,12-dienol. The latter can be easily oxidized to the corresponding acid.

It is increasingly clear that plants perceive and respond to olfactory cues. Yet, knowledge about the specificity and sensitivity of such perception remains limited. We previously documented priming of anti-herbivore defenses in tall goldenrod plants (Solidago altissima) by volatile emissions from a specialist herbivore, the goldenrod gall fly (Eur...

Speciation is typically accompanied by the formation of isolation barriers between lineages. Commonly, reproductive barriers are separated into pre-and post-zygotic mechanisms that can evolve with different speed. In this study, we measured the strength of different reproductive barriers in two closely related, sympatric orchids of the Ophrys insec...

A new isoquinoline quinone system and its iodinated derivatives were isolated from the ascidian tunicate Ascidia virginea Müller 1776 (Phlebobranchia: Ascidiidae). Structures were elucidated by spectroscopic methods and derivatization reactions. Ascidine A (3,7-dihydro-1,8-dihydroxy-4-(4'-hydroxyphenyl)isoquinoline-3,7-dione (1), ascidine B (3,7-di...

We present evidence that cerambycid species that are supposed mimics of vespid wasps also mimic their model’s odor by producing spiroacetals, common constituents of vespid alarm pheromones. Adults of the North American cerambycids Megacyllene caryae (Gahan) and Megacyllene robiniae (Forster) are conspicuously patterned yellow and black, and are bel...

The pollen diet provided by adult bees to their offspring varies immensely. While some species collect pollen on several plants irrespective of their phylogenetic relatedness (polyleges), others collect only on plants within a genus or family (oligoleges). Floral scents play a central role in bee-plant interactions. To locate flowers, polyleges are...

Homalinotus validus is an important pest of babassu palm (Attalea speciosa) cultures in North Brazil. Investigations on the chemical ecology of this species are essential for the development of an integrated pest management system, since attempts to control the pest by conventional insecticides failed. GC/MS and GC/FT-IR analyses of headspace volat...

Chilecomadia valdiviana (Philippi) (Lepidoptera: Cossidae) is an insect native to Chile. The larval stages feed on the wood of economically important fruit tree species such as apple, pear, olive, cherry, and avocado, and also on eucalyptus. This causes weakening and, in case of severe infestation, death of the tree. We report identification of the...

The cocoa weevil Conotrachelus humeropictus is an economically most important pest on cocoa (Theobroma cacao) and cupuaçu (Theobroma grandiflorum) cultures. Knowledge on the pheromone system of this insect is prerequisite for the development of an integrated pest management system. GC/MS-analysis of headspace volatiles revealed the presence of thre...

How signal diversity evolves under stabilizing selection in a pheromone-based mate recognition system is a conundrum. Female moths produce two major types of sex pheromones, i.e., long-chain acetates, alcohols and aldehydes (Type I) and polyenic hydrocarbons and epoxides (Type II), along different biosynthetic pathways. Little is known on how male...

Recently, the distribution of the Mediterranean cedar bark beetle, Phloeosinus aubei Perris (Coleoptera: Scolytidae), has expanded to Central Europe. Reported mostly on cypress in the Mediterranean area, potential host plants in the invaded range include other scale-leafed conifers, such as cultivars of arborvitae, Thuja occidentalis L. To reveal p...

Ceropegia species (Apocynaceae) have deceptive pitfall flowers and exploit small flies as pollinators, supposedly by chemical mimicry. Only preliminary data on the composition of flower scents are available for a single species so far, and the mimicry system is not yet understood in any species. We collected data on basic pollination aspects of C....

Male-specific volatile components, released by the dried bean beetle, Acanthoscelides obtectus, were identified as methyl (E,R)-2,4,5-tetradecatrienoate, methyl (2E,4Z,7Z)-2,4,7-decatrienoate, methyl (2E,4Z)-2,4-decadienoate, octadecanal and the sesquiterpenes (3Z,6E)- and (3E,6E)-α-farnesene. In olfactometer bioassays, pure methyl (E,R)-2,4,5-tetr...

The sex pheromone of the cloaked pug moth, Eupithecia abietaria G€otze, an important cone-feeding pest in spruce seed orchards in Europe, was investigated. Chemical and electrophysiological analyses of pheromone gland extracts of female moths and analogous analyses of synthetic hydrocarbons and epoxides of chain length C19 and C21 revealed (3Z,6Z,9...

Comparative GC/MS analysis of airborne volatiles produced by males and females of the guava weevil Conotrachelus psidii (Coleoptera: Curculionidae: Molytinae) showed the presence of a male-specific electroantennographically active compound identified as (1R,2S,6R)-2-hydroxymethyl-2,6-dimethyl-3-oxabicyclo[4.2.0]octane (papayanol). Release of this c...

Analysis of the pheromone gland extract of females of the click beetle Agriotes sordidus (Illiger), revealed the presence of geranyl hexanoate (GH) and (E,E)-farnesyl hexanoate (FH) in an approximate ratio of 1:1. In the female-released volatiles collected by headspace extraction, GH was a dominant component with FH present only in trace amounts. I...

Representatives of the highly speciose tropical butterfly genus Bicyclus (Lepidoptera: Nymphalidae) are characterized by morphological differences in the male androconia, a set of scales and hair pencils located on the surface of the wings. These androconia are assumed to be associated with the release of courtship pheromones. In the present study,...

Mass spectrometric investigations confirmed the structure of the female produced sex pheromone of the horse-chestnut leafminer Cameraria ohridella Desch. and Dim. to be (8E,IOZ)-8,10-tetradecadienal. Pure samples, prepared in a straightforward synthesis, were highly attractive in field tests and proved to be suitable for monitoring of flight activi...

Two candidate attractants, phenol and 1,4-benzoquinone, a synthetic mixture of typical compounds from green-leaf odours [(Z)-3-hexenyl acetate: (Z)-3-hexen-1-ol: benzaldehyde: (E)-2-hexen-1-ol: 1-hexanol; 100:20:10:1:1] and freshly damaged oak leaves were screened for field attractancy in funnel traps in Hungary. Males of two Rhizotrogus spp. (Cole...

Mass spectrometric fragmentation patterns of alkyl-3, 4- dihydro-2 H-pyranes and alkyl-2, 3-dihydro-4 H-pyran-4- ones are described. Through GC/M S analyses, respective compounds showing unbranched carbon skeletons are identified for the first time as volatile signals of social and solitary bees and of the male moth Hepialus hecta L.

Pyrrolizidine alkaloid derivs. are present in the androconial (male scent) organs of Prittwitzia hymenaea, Mechanitis isthmia veritabilis, Tithorea harmonia furia (Ithomiinae), Amauris echeria, and Euploea sylvester (Danainae). Whereas the ithomiines contain the new pyrrolizidine alkaloid deriv. Me hydroxydanaidoate, the danaines contain the known...

Low molecular weight constituents of 3400 venom sacs of Paravespula vulgaris were extracted with water, diluted acetic acid, and methanol. After conversion to volatile derivatives carbohydrates, amino acids, fatty acids, other constituents of phospho lipids, and biogenic amines were identified by gas chromatography and mass spectrometry. Quantitati...

Mono and polyhalogenated dibenzofurans and dibenzo-p-dioxins are electrochemically reduced in a divided cell in technical methanol at a lead cathode.

Chemical analyses are presented of prominent exocrine glands of queen Bombus terrestris including mandibular, labial and hypopharyngeal glands in the head. Dufour's gland and tarsal glands. A plethora of about 500 substances were identified belonging to various aliphatic compounds including hydrocarbons, various classes of esters, alcohols, methyl...

Ambrosia Beetles, Attractant, Xyloterus 3-Hydroxy-3-methylbutan-2-one was found in equal amounts in the extracts of males and females of three species of ambrosia beetles: Xyloterus domesticus L., Xyloterus signatus F. and Xyloterus lineatus Oliv. The substance may play an important role as an attractant because the concentration is highest in the...

From the volatile constituents of the solitary bee species Panurgus banksianus Kirby and P. calcaratus Scopuli 31 compounds could be identified. The cephalic secretion of P. banksianus is a sex specific m ulticomponent mixture of terpenes and aliphatic carboxylic acid esters while P. calcaratus contains monoterpenes only. The major component in the...

50 volatile constituents of the mandibular gland secretions in males and females of three species of Andrena bees, A. wilkella (Chr.), A. ovatula (K.) and A. ocreata (K.), been identified. The secretions are made up of a series of spiroacetals of four different systems together with monoterpenes and unbranched acyclic compounds. Many of the compone...

Volatile cephalic secretions from females of four cleptoparasitic bee species, Epeolus cruciger(Pz.), E. variegatus, (L.) (Anthophoridae) and Coelioxys (Coelioxys) quadridentata (L.), C.(Schizocoelioxys) mandibularis Nyl. (Megachilidae) were analysed by combined gas chromatography/ mass spectroscopy. There are considerable similarities between the...

The sting of the Neoguinean pseudomyrm ecine ant, Tetraponera sp. (group punctulata) is modified in astructureresembling a drawing pen. These ants do not sting, but smear upon enemies a contact poison. The venomwhich originates from the poison gland is a mixture of eight alkaloids with an original tricyclic ring system. The structure of the majorco...

Volatile secretions from Dufour's glands in three species of Dufourea bees, Dufourea (Halictoides) dentriventris (Nylander), D.(H.) inermis (Nylander) and D. (Dufourea) minuta Lepelletier have been studied by gas chromatography and mass spectrometry. It was found that the secretions are composed of complex blends of straight chain saturated andunsa...

The terpenes camphene, camphor, isopulegol, isoborneol, bomeol and the terpenoid methyl 3-isopropyl-pentanoate are identified from both species while n-nonanal was only found in F. rufa.

Ipsenol, Ipsdienol, and £-myrcenol are male specific compounds of Ips schmutzenhoferi. Overall 46 compounds could be identified from males and females. The diversity of oxygenated terpenes is particularly high in males.

Head extracts of adult workers of the Brazilian stingless bee Scaptotrigona postica (Trigonini, Meliponinae: Apidae) were analysed for volatile substances by gas chrom atography/ mass spectroscopy. Individual worker bees performing clearly defined tasks and representing five age groups were collected. A total of 36 compounds was identified, 22 of w...

The complex volatile secretion from the mandibular glands of Andrena haemorrhoa (Hym., Apoidea) has been analysed by GC/M S. It is composed primarily of three groups of compounds: 1. Spiroacetals of five different systems: two 1,6-dioxyspiro[4.4]nonanes, four 1,6-dioxaspiro[4.5] decanes, two 1,7-dioxaspiro[5.5]undecanes, one 1,6-dioxaspiro[4.6]unde...

Methylmyristate and ethylpalmitate were identified from males and females of the ambrosia beetle Xyloterus domesticus L. The role of these compounds is discussed in connection with a brief survey concerning the occurrence of long-chain fatty-acid esters in other insects and in the phloem of softwood as attractants for bark beetles.

In the primitively eusocial sweat bee, Lasioglossum malachurum, 66 volatile compounds could be identified from queen Dufour's gland secretions. The patterns found in gynes and in old nesting queens differed in the absolute amounts of extractable volatiles as well as in the relative proportions. 3-Methyl-3-butenyl octadecanoate is the main component...

From workers of Mourella caerulea, an extremely rare and primitive species of neotropical stingless bees, 101 cephalic volatiles were identified by GC/MS analyses.

Methyl-3-isopropylpentanoate is identified from the heads of workers and in higher concentration from heads of old queens of Formica polyctena (Förster). In laboratory bioassays this terpenoid ester showed a strong aggression inhibiting effect. While in the abdomina of workers the alarm pheromone undecane is the main compound it is almost completel...

A borókaszú (Phloeosinus aubei Perris, 1855) (Coleoptera: Scolytidae) áttelelô járataiból tél végén kigyûjtött imágók vizsgálata azt mutatta, hogy hazánkban mind a hímek, mind pedig a nôstény bogarak tömegesen áttelelnek. Tavasszal a frissen készített nászjáratok 50%-ban egy pár tartózkodott, 46%-ban egyetlen egy bogár volt jelen, és csak 4%-ban ta...

Females of the parasitoid wasp Trichogramma turkestanica produce the putative polydeoxypropionates (2E,4E,6S,8S,10S)-4,6,8,10-tetramethyltrideca-2,4-diene and (2E,4E,6S,8S,10S)-4,6,8,10-tetramethyltrideca-2,4-dien-1-ol or their enantiomers as sex specific volatiles. The structures were assigned on the basis of GC-MS investigations using synthetic r...

The bark beetles Pityogenes bidentatus and Pityogenes quadridens (Coleoptera, Curculionidae, Scolytinae) are sibling species that feed and reproduce in bark areas on branches of Scotch pine, Pinus sylvestris. To identify aggregation pheromone components of both species, hindguts and head/thoraxes of males and females of both species feeding in host...

Electronic Supplementary Material includes details on structure elucidation and synthesis of spiroacetals and preparation of synthetic mixtures for behavioral experiments

Many pollinators specialize on a few plants as food sources and rely on flower scents to recognize their hosts. However, the specific compounds mediating this recognition are mostly unknown. We investigated the chemical basis of host location/recognition in the Campanula-specialist bee Chelostoma rapunculi using chemical, electrophysiological, and...

Illiberis (Primilliberis) pruni Dyer (Lepidoptera: Zygaenidae) is an orchard pest distributed in China, Korea, the Far East of Russia, Mongolia and Japan. Field investigations organized in Naruto, Tokushima, Japan in 2008-2010 showed an attraction of the males of this species to (2R)-butyl (7Z)-dodecenoate alone and a mixture containing this compou...

Unanswered key questions in bark beetle-plant interactions concern host finding in species attacking angiosperms in tropical zones and whether management strategies based on chemical signaling used for their conifer-attacking temperate relatives may also be applied in the tropics. We hypothesized that there should be a common link in chemical signa...

It is unresolved as to whether fungi that share a common skin habitat might in principal interact. In in vitro screening tests with Candida albicans, Trichophytum rubrum and other common dermatophytes, we found C. albicans releases volatile compounds that inhibit growth of the dermatophytes. By applying (enantioselective) gas chromatography combine...

Specificity in biological signalling systems is often important to keep information private. Foragers of several species of stingless bees deposit chemical marking signals to guide nestmates to food sources. The markings show species-and colony-specific compositions and primarily attract a bee's nestmates. An interesting question is whether the bee...

Unanswered key questions in bark beetle-plant interactions concern host finding in species attacking angiosperms in tropical zones and whether management strategies based on chemical signaling used for their conifer-attacking temperate relatives may also be applied in the tropics. We hypothesized that there should be a common link in chemical signa...

The native leafmining moth Tischeria ekebladella (Lepidoptera: Tischeriidae) feeds on oaks and recently has become a pest of silviculture and urban green areas in central Europe. The behavioral responses of male moths to hexane extracts of whole bodies of calling females or males were tested under laboratory conditions. Only extracts of females eli...

Starting from the enantiomers of limonene, all eight stereoisomers of trans-fused dihydronepetalactones were synthesized. Key compounds were pure stereoisomers of 1-acetoxymethyl-2-methyl-5-(2-hydroxy-1-methylethyl)-1-cyclopentene. The stereogenic center of limonene was retained at position 4a of the target compounds and used to stereoselectively c...

Following our earlier approach to the synthesis of dihydronepetalactones, all eight stereoisomers of trans -fused iridomyrmecins were synthesized starting from the enantiomers of limonene. Combined gas chromatography and mass spectrometry including enantioselective gas chromatography revealed that volatiles released by the endohyperparasitoid wasp...

Xanthomonas campestris is a phytopathogenic bacterium and causes many diseases of agricultural relevance. Volatiles were shown to be important in inter- and intraorganismic attraction and defense reactions. Recently it became apparent that also bacteria emit a plethora of volatiles, which influence other organisms such as invertebrates, plants and...

Social parasitism is widespread in many groups of social living hymenopteran species and has also evolved in the genus Bombus. Cuckoo bumblebees (subgenus Psithyrus) are obligate brood parasites in nests of other bumblebee species. After nest usurpation and the killing of the host queen, the parasite female has to control worker reproduction in ord...

The family of cecidomyiid midges (Diptera: Cecidomyiidae) exhibits diversified patterns of life history, behavior, host range, population dynamics and other ecological traits. Those that feed on plants include many important agricultural pests; most cultivated plants are attacked by at least one midge species. Several features of the reproductive b...

Sexually deceptive orchids of the genus Ophrys attract male insects for pollination. Pollinator attraction is achieved by mimicking sex pheromones of virgin females of their pollinators, mostly bee species. In earlier investigations, we showed that the phylogenetically distinct Ophrys species O. chestermanii and O. normanii on Sardinia attract thei...

Tackifier resins play an important role as additives in pressure sensitive adhesives (PSAs) to modulate their desired properties. With dependence on their origin and processing, tackifier resins can be multicomponent mixtures. Once they have been incorporated in a polymer matrix, conventional chemical analysis of tackifiers usually tends to be chal...