Chemical Communication and Reproduction Partitioning in Social Wasps

Social wasps encompass species displaying diverse social organization regarding colony cycle, nest foundation, caste differences (from none to significant dimorphism) and number of reproductive queens. Current phylogenetic data suggests that sociality occured independently in the subfamily Stenogastrinae and in the Polistinae+Vespinae clade. In most species, including those with the simplest social organization, colony reproduction is monopolised by a single or few females. Since their nest mates can also develop ovaries and lay eggs, dominant females must somehow inhibit them from reproducing. Physical interactions in the form of open aggression or, usually, ritualised dominance by the fertile females contribute to fertility inhibition in several species, but it is unlikely to function in large colonies. In the latter case, reproduction within the colony is likely to be regulated through pheromones. Relatively little is known about these semiochemicals. Studies on all the three social wasp subfamilies, revealed that cuticular hydrocarbon components differ in abundance between egg-laying and not egg-laying females and that their composition depends on fertility status. In several species, females have been reported to manifestly react towards females with activated ovaries, but there is little evidence to support the hypothesis that fertile individuals are either recognized through their CHC composition, or that over-represented CHC constituents can inhibit fertility. Moreover, very little information exists on the possibility that exocrine glands release fertility signals or chemicals inhibiting fertility.     

Chemical mate recognition and release of male sexual behavior in polybiine wasp,Belonogaster petiolata (Degeer) (Hymenoptera: Vespidae)

The results of bioassays using freshly killed gynes ofBelonogaster petiolata (Degeer) and hexane extracts of their tagmata and abdominal glands provide evidence for the existence of chemical signals in the venom, thorax, and head of gynes that serve as mate recognition cues and releasers of copulatory behavior in conspecific males. Attraction of males to the source of the chemicals occurs over short distances (a few centimeters).     

Chemical analysis of sternal gland secretion of paper waspPolistes dominulus (Christ) and its social parasitePolistes sulcifer (Zimmermann) (Hymenoptera: Vespidae)

The secretion of the tegumental glands of the fifth and sixth gastral sternites ofP. dominulus and of its social parasiteP. sulcifer was analyzed by gas chromatography-mass spectrometry. Seven long-chain carboxylic acids have been identified: hexadecanoic, octadecadienoic and octadecenoic acids are the major components of the gland secretion ofP. dominulus and octadecenoic acid the main compounds ofP. sulcifer sternal gland secretion. The same carboxylic acids have been found on the nest pedicel.     

Alarm response to venom by social waspsPolistes exclamans andP. fuscatus (Hymenoptera: Vespidae)

The venoms ofPolistes exclamans andP. fuscatus elicit alarm behavior and attract attacking wasps. The response is not species specific, for both hetero- and conspecific venoms elicit similar responses in both species. A test in a wind tunnel provided no support for the hypothesis that alarmed wasps release an alarm pheromone on the nest.     

Identification of ant repellent allomone produced by social waspPolistes fuscatus (Hymenoptera: Vespidae)

Two active components were isolated from the ant repellent secretion produced by glandular cells on the sixth (terminal) gastral sternite ofPolistes fuscatus (F.) females. One of the components was identified as methyl palmitate. Field bioassays with synthetic methyl palmitate showed it had repellent activity againstSolenopsis geminata (F.)Forelius pruinosus (Roger), andPheidole sp. The effectiveness of the repellent was greater againstF. pruinosus andPheidole sp. than againstS. geminata. Four methyl ester homologs of methyl palmitate also were field tested for repellent activity: methyl myristate had repellent activity against all three ant species, whereas methyl stearate, methyl linoleate, and methyl linolenate exhibited no repellency.     

Chemical mimicry in a parasitoid (Hymenoptera: Eucharitidae) of fire ants (Hymenoptera: Formicidae)

A wasp (Orasema sp.) parasitic on the fire ant,Solenopsis invicta Buren, develops to the adult stage within the ant colony, where wasp larvae are ectoparasitic on ant pupae. This phase of the parasite's life cycle requires a mechanism of integration into the host colony. Gas Chromatographic profiles of hexane soaks of various stages of the parasite and host suggest that during development within the ant colony the parasite acquires the colony odor of the host through a passive mechanism, based on simple contact and other social interactions. No parasite-specific components were observed. After leaving the host nest as adults, the parasite biosynthesizes a parasite-specific cuticular compound, while retaining residual amounts of the host acquired components. This complicated scenario is consistent with current knowledge of nestmate recognition and the preferential treatment of ant workers to their brood.     

Venom Source of a sex pheromone in the social waspPolistes fuscatus (Hymenoptera: Vespidae)

Females ofPolistes fuscatus possess a sex pheromone in the venom gland and sac. The pheromone attracts males from short distances and releases male copulatory behavior.     

Specificity of Systemically Released Cotton Volatiles as Attractants for Specialist and Generalist Parasitic Wasps

Cotton plants under herbivore attack release volatile semiochemicals that attract natural enemies of the herbivores to the damaged plant. The volatiles released in response to herbivory are not only released from the damaged leaves but from the entire cotton plant. We found that cotton plants that released myrcene, (Z)-3-hexenyl acetate, (E)--ocimene, linalool, (E)-4,8-dimethyl-1,3,7-nonatriene, (E)--farnesene, and (E, E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene systemically from undamaged leaves of caterpillar damaged plants were attractive to the generalist parasitoid Cotesia marginiventris and the specialist parasitoid Microplitis croceipes. Plants from which the caterpillar damaged leaves were removed and that released those compounds systemically were significantly preferred over undamaged control plants in two-choice experiments in a flight tunnel. Artificially damaged cotton plants that released green leafy volatiles and constitutive terpenoids were less attractive for M. croceipes and C. marginiventris. Only C. marginiventris preferred artificially damaged plants over undamaged control plants, whereas M. croceipes showed no preference. The apparent lack of specificity of systemically released compounds in response to different herbivores feeding on the lower leaves is discussed.     

Composition of Chemical Attractants Affects Trap Catches of the Australian Sheep Blowfly, Lucilia cuprina, and Other Blowflies

Numbers of Lucilia cuprina (Australian sheep blowfly), Chrysomya spp., and Calliphora spp. blowflies caught on sticky traps baited with various synthetic attractants or a standard liver/sodium sulfide attractant in western Queensland were recorded. Numbers of each genus collected were influenced by the composition of the chemical attractants. Attractant mixtures based on 2-mercaptoethanol, indole, butanoic/pentanoic acid, and a sodium sulfide solution gave 5- to 20-fold higher L. cuprina catches than the liver standard. These blends attracted similar numbers of Chrysomya spp. (0.85-2.7x) and fewer Calliphora spp. (0.02-0.2x) compared to the liver standard. These synthetic attractants were more effective and selective for L. cuprina than the standard liver/sodium sulfide attractant, and they can be packaged in controlled-release dispensers to generate constant, prolonged release of the attractant.     

Ant repellent effect of the sternal gland secretion ofPolistes dominulus (Christ) andP. sulcifer (Zimmermann). (Hymenoptera: Vespidae)

The long-chain carboxylic acids identified in the sternal gland secretion ofPolistes dominulus andP. sulcifer females were tested individually on three species of ants,Crematogaster scutellaris, Formica cunicularia, andLasius sp., in order to verify if they have a repellent effect. The unsaturated acids (palmitoleic, linoleic, and oleic) act as repellents of all three ant species, while the saturated acids (lauric, myristic, palmitic, and stearic) have no effect. The mixture reproducing the secretion of the sternal glands ofP. dominulus maintained its repellency for at least four days.     

Chemical communication during tandem running inPachycondyla obscuricornis (Hymenoptera: Formicidae)

Communication during tandem running inPachycondyla obscuricornis is chemically mediated by a pheromone produced in the pygidial gland, which is composed of a cluster of gland cells and an associated reservoir located beween the 6th and 7th tergites of the gaster. The secretion of the gland appears to be transferred to the hindlegs of a tandem pair leader by a series of self-grooming behaviors that occur prior to the formation of a tandem pair. During tandem running, the antennae of the following ant are kept in close contact with the leader's hindlegs and therefore with the chemical signal that provides a communicative bond between individuals.Dedicated to the memory of Robert E. Silberglied.     

Chemical communication in the dacetine antDaceton armigerum (Hymenoptera: Formicidae)

Contrary to previous assumptions,Daceton armigerum, the largest ant in the myrmicine tribe Dacetini, employs trail communication. We identified two anatomical sources of trail pheromones: Trails drawn with poison gland contents can last for more than seven days. Trails drawn with the newly discovered sternal glands (in the VIth and VIIth abdominal sternites) are effective but relatively short-lived. In addition, our bioassays revealed that the contents of the mandibular glands elicit alarm behavior, and secretions from the pygidial gland release attraction. When tested with artificial poison gland trails from seven other myrmicine species,Daceton did not exhibit trail following behavior. We confirmed, however, previous findings thatAtta respond toDaceton poison gland trails andSolenopsis followDaceton Dufour's gland trails.     

Chemical and behavioral studies on dufour gland contents ofManica rubida (Hymenoptera: Formicidae)

The Dufour gland ofManica rubida contains a simple mixture of (Z, E)-α-farnesene and (Z, E)-α-homofarnesene with tiny amounts of other faraesene, homofarnesene, and bishomofarnesene isomers. The gland also contains a mixture of very volatile compounds, chiefly acetone, with smaller amounts of acetaldehyde, ethanol, propanol, isobutyraldehyde, butenone, and butanone. The workers ofM. rubida are not attracted to these highly volatile compounds as are workers ofMyrmica species, butM. rubida workers show a strong increase of linear speed when stimulated by a freshly isolated gland. This response of increased speed of bothM. rubida andM. trubra to their own or each other's Dufour gland secretion is consistent with the presence of the farnesenes in them both.     

Behavioural Evidence and Chemical Identification of a Female Sex Pheromone in Anagrus atomus (Hymenoptera: Mymaridae)

Journal of Chemical Ecology - Anagrus atomus (L.) is an egg parasitoid involved in the biological control of Empoasca vitis (Göthe) in vineyards. Sex pheromones play a crucial role in mate...     

Chemical stimuli in host-habitat location byLeptopilina heterotoma (Thomson) (Hymenoptera: Eucoilidae), a parasite ofDrosophila

Chemical stimuli play an important role in the process of searching for a host habitat by parasitic wasps. Volatile compounds originating from host habitats and/or hosts are the cues that enable such a location.Leptopilina heterotoma, a larval parasite ofDrosophila, is attracted to the food of its host, baker's yeast. Analysis of the fermentation products of baker's yeast, using a mass spectrometer, and olfactometer studies indicate that three fermentation products of this yeast, the main component of the host habitat in our laboratory, attractL. heterotoma: ethanol (5%), ethyl acetate (10^–2, 10^–3%), and acetaldehyde (1%). A combination of these three compounds, however, cannot compete with baker's yeast in attracting the parasites. Thus other factors, such as different compounds, concentrations, and/or combinations, also, play a role and remain to be tested.Leptopilina heterotoma does not use host-related olfactory cues in long-distance habitat location as it cannot distinguish between host habitat and host habitat with hosts.     

Plant allelochemicals and insect parasitoids effects of nicotine onCotesia congregata (say) (Hymenoptera: Braconidae) andHyposoter annulipes (Cresson) (Hymenoptera: Ichneumonidae)

Parasitoids developing within tobacco hornworms or fall army-worms exhibit significant differences in development and survival depending on whether their hosts fed on nicotine-free or nicotine-containing diets. The effects of nicotine were more severe on the relatively less adapted parasitoid,H. annulipes than the specialist parasitoid,Cotesia congregata. Labeled alkaloid originally placed in herbivore diet was incorporated in several parasitoid tissues. These results suggest that interactions between plant allelochemicals and parasitoids should be considered in the development of theory on insect herbivory and plant defense.Scientific article No. A4408, Contrib. No. 7397 of the Maryland Agricultural Experiment Station, Department of Entomology. Research supported by USDA. Competitive Grant No. 59-2241-1-1-749-0 and NSF grant BSR-84-00614.Mention of a commercial product does not constitute an endorsement.     

碳一化工产品发展展望(1)甲醇、合成氨(待续)

简述碳-化工产品(甲醇和合成氨)供求状况,着重分析了我国碳-化工产品生产、消费现状,并对其未来发展进行了预测.     

Mandibular glands of stingless bees (Hymenoptera: Apidae): Chemical analysis of their contents and biological function in two species ofMelipona

Workers ofMelipona fasciata andM. interrupta triplaridis respond to their respective mandibular gland extracts with alarm recruitment and defensive behavior. Workers rapidly exit from the nest entrance, land on an intruding object, and bite with the mandibles while vibrating the flight muscles. These behaviors are accompanied by the release of the contents of the mandibular glands. Colonies of both species exhibited greater response to their own mandibular gland extracts than to those of other stingless bee species. Chemical analysis identified 2-heptanol as the major component in hexane extracts of each species. Undecane was a constituent of both species; skatole and nerol were identified only in extracts ofM. i. triplaridis.     

Attraction of Dibrachys cavus (Hymenoptera: Pteromalidae) to its Host Frass Volatiles

The European grapevine moth, Lobesia botrana (Lepidoptera: Tortricidae), is a polyphagous insect able to develop on grapes and wild plants. We tested the hypothesis that the parasitoid Dibrachys cavus (Hymenoptera: Pteromalidae) uses the larval frass in its host search. A two-armed olfactometer was used to measure the attractiveness of L. botrana larvae, their silk, or their frass after larvae were fed on different host plants. Frass of three Lepidoptera (L. botrana, Eupoecillia ambiguella, Sphinx ligustri) and one Orthoptera (Chorthippus brunneus) was assayed, but only L. botrana was used to test an effect of the larval host plant (two grape cultivars and three other plant species) to D. cavus females. Larvae without frass did not attract D. cavus whatever their origin, but their frass was attractive at a dose of 2–3 days equivalent of larval frass production. The silk produced by a single larva (L. botrana) was not attractive to D. cavus. The parasitoid was most attracted to the odor of S. ligustri; the frass of L. botrana was more attractive than that of E. ambiguella, irrespective of the species on which D. cavus had been reared. There was no difference in attractiveness of frass collected from L. botrana raised on food containing different plants. Chemical extracts using five different polarity solvents (acetone, dichloromethane, hexane, methanol, and water) differed in attractiveness to D. cavus. Water and dichloromethane were the most attractive. This suggests that a complex volatile signal made from intermediate to polar volatiles may be involved in attraction. D. cavus used frass to discriminate between different potential host species. Our results revealed that the larval food of L. botrana did not modify frass attractiveness, but that the moth species did.     

手性化学工业的发展（一）

传统化学仍是获得单一对映体的主要方法,传统化学也可能达到对映体纯产品的目标,例如结晶动力学拆分制备(R)-氟比洛芬,哌啶诱导构型转换制备L-核糖。手性源和拆分方法仍多于催化不对称合成,而催化不对称合成化学的核心是催化剂的选择,不对称环氧化在工业上取得了巨大成功。