(Z)-9-Nonacosene—Major Component of the Contact Sex Pheromone of the Beetle Megacyllene caryae

Male Megacyllene caryae (Gahan) (Coleoptera: Cerambycidae) respond to females only after touching them with their antennae, indicating that mate recognition is mediated by a contact sex pheromone. Gas chromatography-mass spectrometry analyses of whole-body solvent extracts of male and female M. caryae revealed substantial differences in hydrocarbon profiles, with nearly half of the compounds in the extracts from females being absent from those of males. Biological activities of fractions of crude extracts of females, and reconstructed blends of the most abundant straight-chain (nC₂₇, nC₂₈, nC₂₉), methyl-branched (2Me-C₂₆, 9Me-C₂₉, 11, 13, 15Me-C₂₉), and unsaturated (Z9:C₂₉, Z13:C₂₉, Z14:C₂₉, Z13:C₃₁, Z14:C₃₁, Z15:C₃₁) compounds in extracts of females were tested in arena bioassays, assessing four steps in the mating behavior sequence of males (orientation, arrestment, body alignment, mounting and attempting to couple the genitalia). Males showed limited response to dead females treated with fractions of the crude extract or blends of synthetic straight-chain and methyl-branched alkanes, but responded strongly to the blend of synthetic monoenes. Further trials determined that the complete sequence of mating behaviors, up to and including coupling the genitalia, was elicited by Z9:C₂₉ alone. Z9:C₂₉ is a homolog of the contact pheromone (Z9:C₂₅) of the congener M. robiniae (Förster). Previous work with M. robiniae suggested that wipe sampling of cuticular hydrocarbons of females by solid phase microextraction yielded a more representative profile of components actually encountered by a male’s antennae, and so provided a more readily interpretable profile of potential semiochemicals present in the wax layer than does solvent extraction. We tested this hypothesis by comparing hydrocarbon profiles of female M. caryae by the two sampling methods. Z9:C₂₉ was the only compound among the dominant hydrocarbons that was present in higher abundance in SPME than in solvent extracts (∼12% vs. ∼8%, respectively), supporting this hypothesis.Electronic supplementary material Supplementary material to this paper is available in electronic form at.     

Interspecific Pheromone Cross-Attraction Among Soybean Bugs (Heteroptera): Does Piezodorus hybneri (Pentatomidae) Utilize the Pheromone of Riptortus clavatus (Alydidae) as a Kairomone?

The chemical and ecological function of cross-attraction of Piezodorus hybneri (Pentatomidae) to the Riptortus clavatus (Alydidae) pheromone (a mixture of three components) was studied. In a field attraction test using traps with synthetic pheromone components, P. hybneri was attracted to (E)-2-hexenyl (E)-2-hexenoate, a component of the R. clavatus pheromone. Other components had neither an additive nor a synergistic effect on the attraction of P. hybneri. Neither (E)-2-hexenyl (E)-2-hexenoate nor other components of the R. clavatus pheromone were detected in volatiles or whole-body extracts of P. hybneri adults by gas chromatographic analysis. In addition, (E)-2-hexenyl (E)-2-hexenoate could not be found in volatiles of soybean plants. Therefore, it appears that P. hybneri responds to a component of the R. clavatus pheromone that is not emitted by P. hybneri itself. We discuss this interspecific pheromone cross-attraction of the soybean bug and hypothesize that P. hybneri utilizes the pheromone of its competitor as a kairomone for host location.     

Are Insect-Synthesized Retronecine Esters (Creatonotines) the Precursors of the Male Courtship Pheromone in the Arctiid Moth Estigmene acrea?

The pyrrolizidine alkaloid (PA) profiles were determined for adults of the polyphagous arctiid Estigmene acrea, which as larvae had fed on artificial diet supplemented with Crotalaria-pumila powder with known concentrations of PAs. The larvae always had a free choice between alkaloid-containing and plain diets. The alkaloid profiles of adults revealed a striking sexual dimorphism. Both sexes contained macrocyclic PAs of the monocrotaline type sequestered from the diet and, in addition, a substantial proportion of supinidine and retronecine esters synthesized by the insects from necine bases derived from the dietary alkaloids and necic acids of insect origin. These insect alkaloids accounted for 35% and 55% of total PAs in males and females, respectively. The difference was that in females the retronecine esters (creatonotines) made up 58 g (43% of total PAs), while males contained a fivefold lower proportion, 12 g (13%). Four of the ten male individuals analyzed were found devoid of creatonotines. Based on the experimental data in combination with evidence from the literature, it is suggested that the creatonotines are direct pheromone precursors in E. acrea. It is hypothesized that this may represent a general mechanism of hydroxydanaidal formation from diverse macrocyclic PAs in arctiids.     

Synergistic Effect of Ethanol to α-Pinene in Primary Attraction of the Larger Pine Shoot Beetle, Tomicus piniperda

-Pinene and ethanol were released in the approximate proportions 1:0.1, 1:0.9 and 1:9 (at 21°C). Ethanol, released in the range of 3–279 mg/day, generally synergized the attraction of T. piniperda to -pinene (30 mg/day at 21°C), although attraction to the mixtures varied within and between years. The low release rate of ethanol together with -pinene attracted a significantly higher number of beetles than -pinene alone in 1995, April of 1996, and in 1997. Lures with the medium release rate of ethanol were the most attractive only in March of 1996. The high dose of ethanol significantly synergized attraction to -pinene in 1995 and 1997. The variable attraction of T. pinipeda to ethanol and -pinene at various release rates and proportions may be due to the temperature dependent nature of beetle antennal sensitivity. At ambient temperatures of 10–13°C. T. piniperda was most attracted to the lures with -pinene and high release rates of ethanol, at 14–17°C it was most attracted to those with medium release rates of ethanol, and at 18°C and higher it was most attraacted to those with low release rates of ethanol.     

A Selfish Function of a “Social” Gland? A Postpharyngeal Gland Functions as a Sex Pheromone Reservoir in Males of the Solitary Wasp Philanthus triangulum

The postpharyngeal gland (PPG) has long been assumed to be restricted to ants, where it mainly functions in the maintenance of social integrity. Recently, a PPG has been described in both sexes of a solitary digger wasp, the European beewolf, Philanthus triangulum (Hymenoptera, Crabronidae). Female beewolves use the contents of their PPG to embalm their honeybee prey to delay microbial growth. Here we show that in male beewolves, the PPG serves as a reservoir of the pheromone used to scent-mark their territories. Gas chromatography-mass spectrometry (GC-MS) analysis of PPG contents identified 55 substances including long-chain aliphatic hydrocarbons, and 13 substances with functional groups. The composition was consistent with the composition of the marking pheromone of male European beewolves described earlier. Comparisons of the PPG contents, and total-head extracts showed a strong congruency, suggesting that total-head extracts can be used for the analysis of marking secretion in beewolves. Furthermore, we found a dimorphism in the composition of the PPG contents, based on significant differences in the proportions of seven compounds between the two morphs.     

Studies of the properties of polycrystalline (Na,Pb) β-aluminas

Samples with rectangular cross section were cut from bars of polycrystalline sodium β″-alumina. They were converted to (Na,Pb) β″-aluminas in molten mixtures of the composition xNaCl + (1−x)PbCl₂ at 700°C in air. After conversion the specimens were characterized by optical microscopy and REM. It was verified that the concentration of sodium and lead ions was even across the thickness of the sample. The formation of cracks was observed at larger extents of exchange. The extent of ion exchange in the solid electrolyte was determined from the weight change and chemical analysis. The weight change yields values for the exchange which are too large. Measurements of the conductivity by our four-probe technique are feasible above 200°C and are discussed as a function of temperature and composition.     

Synthesis of Cu@CF@SBA15: A Versatile catalysts for (i) reduction of dyes,trifluralin, Synthesis of (ii) DHPMs by Biginelli reaction and (iii) 1,2,3-triazole derivatives by ‘Click reaction’

Herein, we are reporting a facile route to synthesize magnetically separable Cu nanoparticle loaded CoFe₂O₄@SBA15 catalysts, which exhibits high catalytic activity towards (i) reduction of various synthetic dyes, trifluralin, (ii) synthesis of DHPMs via Biginelli reaction pathway in solventless condition and (iii) 1,2,3-triazole derivatives by ‘Click reaction’ in aqueous medium. To the best of our knowledge, this is the first time one single catalyst is reported which shows its high activity for these three important reactions.     

Functional Paracyclophanes: Synthesis of [2.2]Paracyclophanemethyldithiocarbonates Using Thione–Thiol Rearrangement of S,O-Dithiocarbonates (Benzyl Schönberg Rearrangement) at Mild Conditions

A pathway to benzylic [2.2]paracyclophane thiol derivatives was investigated using the benzyl Schönberg rearrangement.     

How to Spoil the Taste of Insect Prey? A Novel Feeding Deterrent against Ants Released by Larvae of the Alder Leaf Beetle,Agelastica alni

Chemical defense of leaf beetle larvae (Chrysomelidae) against enemies is provided by secretions containing a wide range of deterrent compounds or by unpalatable hemolymph constituents. Here we report a new, very strong feeding deterrent against ants released by larvae of the alder leaf beetle Agelastica alni when attacked. The larvae release a defensive fluid from openings of pairwise, dorsolaterally located tubercles on the first to the eighth abdominal segments. The fluid, consisting of hemolymph and probably a glandular cell secretion, has previously been shown to contain a very stable, non‐volatile feeding deterrent. The major deterrent component was isolated by repeated HPLC separation and analyzed by NMR and MS. The compound proved to be γ‐L ‐glutamyl‐L ‐2‐furylalanine ( 1 ), a novel dipeptide containing the unusual amino acid L ‐2‐furylalanine. This amino acid, although synthetically well known, has not previously been reported from natural sources. The absolute configuration of the natural compound was elucidated by enantioselective gas chromatography after derivatization. The structure of the dipeptide was verified by the synthesis of several isomeric dipeptides. In bioassays a concentration of 1 μg μL^?1 was sufficient to deter polyphagous Myrmica rubra ants from feeding.     

Comparison of the structural properties of compounds containing the XSSX moiety (X = H,Me, R,Cl, Br,F, OR)

A comparison of the structural parameters of a wide variety of compounds containing the S–S bond is summarized.     

Preparation of Polymers Containing Metal–Metal Bonds along the Backbone Using Click Chemistry

The [(η⁵-C₅H₄(CH₂)₃OC(O)(CH₂)₂C≡CH)Mo(CO)₃]₂ complex (1) was synthesized and used to explore the feasibility of using the Huisgen cycloaddition reaction (a click reaction) to incorporate molecules with metal–metal bonds into polymer backbones. In a model reaction, coupling of 1 with benzyl azide was observed in 24 h using Cp*Ru(PPh₃)₂Cl as a catalyst. In contrast, the reaction of 1 with benzyl azide using a CuBr/ligand catalyst (where the ligand is either PMDETA or bipyridine), resulted in disproportionation of the Mo–Mo unit in 1. Complex 1 was also coupled with telechelic azide-terminated polystyrene oligomers. With either the CuBr/PMDETA or CuBr/bipyridine catalyst, disproportionation of the Mo–Mo bonded unit occurred before complete coupling was observed. The reaction was also slow when the Cp*Ru(PPh₃)₂Cl catalyst was used; however, no disproportionation products were observed and a high molecular weight polymer (M _n = 120,000 g/mol) was produced. The Cp*Ru(PPh₃)₂Cl catalyst was also used to couple 1 with azide-terminated poly(ethylene glycol). After 15 h, this reaction produced a polymer with M _n = 73,000 g mol⁻¹. It is concluded that, although somewhat slow, click chemistry using the Cp*Ru(PPh₃)₂Cl catalyst is an excellent method for synthesizing high molecular weight polymers with metal–metal bonds along the backbone.     

Polar Metabolites Synergize the Activity of Prostaglandin F<Subscript>2α</Subscript> in a Species-Specific Hormonal Sex Pheromone Released by Ovulated Common Carp

Many species of teleost fish detect and release F prostaglandins (PGFs), but the specific identities of these compounds and how they function as species-specific pheromones have yet to be resolved. This study addressed these questions in the common carp. An initial set of experiments established that mature male common carp were attracted to chemicals released by ovulated conspecifics, whereas the odor of female goldfish, a close relative, was less attractive. Tests of fractionated holding water from ovulated carp revealed that only the non-polar fraction was attractive on its own. Mass spectrometry and immunoassay next demonstrated that the non-polar fraction contained large quantities of prostaglandin F_2α (PGF_2α), 15keto-prostaglandinF_2α, and 13,14-dihydro-15keto-prostaglandin F_2α (100 g fish released over 1 μg of all 3 PGFs per h at a ratio of 1.0: 1.7: 0.7). Ovulated goldfish released the same three PGFs but at a slightly greater rate and in a different ratio. Tests of synthetic mixtures of these PGFs revealed that the carp-specific mixture attracted male carp but was no better than the goldfish-specific mixture or PGF_2α alone and that PGF_2α was just as attractive as mixture of all three PGFs. A final set of attraction tests revealed that although PGF_2α could explain all of the activity of the non-polar portion of female carp holding water, it could not explain the entire activity of female water but that a mixture of PGFs and the polar fraction could. We conclude that ovulated female carp release a multi-component sex pheromone complex that is comprised of PGF_2α and unknown species-specific polar compound(s) that synergize the activity of the former. The pheromone also might be useful in controlling this invasive species. The observation that a fish hormonal sex pheromone incorporates bodily metabolites in addition to relatively common hormonal products demonstrates a mechanism by which species specificity may be conferred to this common type of sex pheromone.     

Extraordinary Adaptive Plasticity of Colorado Potato Beetle: “Ten-Striped Spearman” in the Era of Biotechnological Warfare

Expanding from remote areas of Mexico to a worldwide scale, the ten-striped insect, the Colorado potato beetle (CPB, Leptinotarsa decemlineata Say), has risen from being an innocuous beetle to a prominent global pest. A diverse life cycle, phenotypic plasticity, adaptation to adverse conditions, and capability to detoxify or tolerate toxins make this insect appear to be virtually “indestructible”. With increasing advances in molecular biology, tools of biotechnological warfare were deployed to combat CPB. In the last three decades, genetically modified potato has created a new challenge for the beetle. After reviewing hundreds of scientific papers dealing with CPB control, it became clear that even biotechnological means of control, if used alone, would not defeat the Colorado potato beetle. This control measure once again appears to be provoking the potato beetle to exhibit its remarkable adaptability. Nonetheless, the potential for adaptation to these techniques has increased our knowledge of this pest and thus opened possibilities for devising more sustainable CPB management programs.     

Common Carp Implanted with Prostaglandin F2α Release a Sex Pheromone Complex that Attracts Conspecific Males in Both the Laboratory and Field

When ovulated, female fish of many species are known to release a F-prostaglandin-derived sex pheromone that attracts conspecific males. Recently, this pheromone was identified in the common carp as a mixture of prostaglandin F_2α (PGF_2α) and unidentified body metabolites, which we termed a ‘pheromone complex.’ The present study sought to test the activity of this pheromone complex in the field by developing a system using carps implanted with PGF_2α as pheromone donors. An initial experiment determined that osmotic pumps that delivered up to 0.4 mg of PGF_2α per hour could be implanted into carp without any apparent effects on their health. A second experiment found that PGF_2α-implanted male and female carp released biologically relevant (and equivalent) quantities of PGF_2α, along with two of its seemingly inactive metabolites, for up to 2 weeks. Laboratory experiments demonstrated that the odor of PGF_2α-implanted carp was highly attractive to male conspecifics, and included necessary body metabolites; it attracted males as strongly as ovulated carp odor, and much better than PGF_2α alone. Finally, a field test demonstrated that PGF_2α-implanted female carp attracted mature male, but not female carp, from a distance of 20 m. This is the first demonstration of the activity of a PGF_2α-based pheromone in a natural environment and confirms the use of a PGF-pheromone complex in the carp. We suggest that the implant technique may be useful in future studies of how PGF pheromones function and could be further developed to attract invasive fish for use in control.     

Compatibilizing capability of poly(β-hydroxybutyrate-,co-ε-caprolactone) in the blend of poly(β-hydroxybutyrate) and poly(ε-caprolactone)

In order to increase the miscibility in the blend of poly(β-hydroxybutyrate) [PHB] and poly(ε-caprolactone) [PCL], PHB/PCL copolyesters were used as compatibilizers. These PHB/PCL copolyesters were synthesized by transesterification in solution phase. The melting point [T_m] depression, which was not observed in PHB/PCL blend without compatibilizer, was observed when PHB/PCL copolyesters as compatibilizers were added to the PHB/PCL blend system. As the amount of compatibilizer added to the blend increased, the crystallization temperature [T_c] of PCL in the blend increased and T_c of PHB in the blend decreased. The difference in T_c between PHB and PCL was gradually reduced. When the sequence length of PHB block and PCL block in the PHB/PCL copolyester increased, the miscibility of the blend increased. This is evidenced by the depression in the T_m of PHB and PCL in the blend and by the decrease in the difference of T_c between PHB and PCL. From the polarizing optical micrographs, the phase separation in PHB/PCL blend was observed. However, in the presence of PHB/PCL copolyester, the spherulite of PHB grows in equilibrium with one phase melt. Received: 27 July 1998/Revised version: 12 October 1998/Accepted: 4 November 1998     

Effect of Yb,Gd, and Nd Substitution at the Sr Site on the Metal–Insulator Transition of the (Bi,Pb)-2212 System

Resistivity measurements in the temperature range (64–300 K) were used to study the metal–insulator transition (MIT) driven by a change in the carrier concentration of the Bi_1.7Pb_0.4Sr₂Ca_1.1Cu_2.1O_y [(Bi,Pb)-2212] system. The carrier-concentration is changed by substituting rare-earth (RE) elements (Nd, Gd, and Yb) at the Sr site of (Bi,Pb)-2212. Results show that at higher levels of RE substitution, MIT occurs in (Bi,Pb)-2212, during which the resistivity becomes minimum at a particular temperature(T_min) for a particular doping level. Below this temperature, resistivity increases with a decrease in the temperature and vice versa, showing an insulating and a metallic nature, respectively. This T_min and the carrier concentration at which MIT occurs depend on the substituted RE.