Optimization of a Phenylacetaldehyde-Based Attractant for Common Green Lacewings (<Emphasis Type="Italic">Chrysoperla carnea s.l.</Emphasis>)

In field trapping tests, the catch of Chrysoperla carnea sensu lato (Neuroptera: Chrysopidae) increased when acetic acid was added to lures with phenylacetaldehyde. The addition of methyl salicylate to the binary mixture of phenylacetaldehyde plus acetic acid increased catches even further. The ternary blend proved to be more attractive than β-caryophyllene, 2-phenylethanol, or 3-methyl eugenol (compounds previously described as attractants for chrysopids) on their own, and no influence on catches was recorded when these compounds were added as fourth components to the ternary blend. There were minimal changes in activity when (E)-cinnamaldehyde or methyl anthranylate (both evoking large responses from female or male antennae of C. carnea in this study) were added, although both compounds showed significant attraction on their own when compared to unbaited traps. In subtractive field bioassays with the ternary mixture, it appeared that the presence of either phenylacetaldehyde or methyl salicylate was important, whereas acetic acid was less so in the ternary mixture. The ternary blend attracted both female and male lacewings at sites in southern, central, and northern Europe. Possible applications of a synthetic attractant for lacewings are discussed.     

Species-specific,two-component,volatile signals in two sympatric ant-lion species:Synclysis baetica andAcanthaclisis occitanica (Neuroptera,Myrmeleontidae)

The thoracic glands of males in two ant-lion speciesSynclysis baetica andAcanthaclisis occitanica, which occur sympatrically in Israel, were found to contain a volatile secretion with two-component blends of nerol oxide and (R,Z)-6-tridecen-2-ol (approx 15) and nerol oxide and 10-homonerol oxide (approx. 12), respectively. Chemical analyses were performed using gas chromatography-mass spectrometry, chiral gas chromatography, and ozonolysis, and the proposed structures were confirmed by synthesis. The species-specific, few-component volatile signals are thought to function as a reproductive isolation mechanism between the two sympatric species. Biochemical relationships between the nerol derivatives and between the unsaturated secondary alcohols are discussed.     

Two New Fossil Lacewing Species from the Middle Jurassic of Inner Mongolia, China (Neuroptera: Grammolingiidae)

Two new species of lacewings are described and illustrated from the Jiulongshan Formation (Middle Jurassic) of Inner Mongolia, China: Leptolingia calonervis sp. nov. and Litholingia ptesa sp.nov. (Grammolingiidae). The species can be distinguished by the following features: the outermost branch of MP2 on the hind wing did not reach the margin of wing in Leptolingia calonervis sp. nov.;the second branch of Rs forked deeply while other branches of Rs forked much later in Litholingia ptesa sp. nov..     

Semiochemistry of the Goldeneyed Lacewing Chrysopa oculata: Attraction of Males to a Male-Produced Pheromone

Gas chromatographic-electroantennographic detection (G3C-EAD) experiments showed that antennae of males and females of the goldeneyed lacewing, Chrysopa oculata Say (Co. = Chrysopa), consistently responded to four compounds extracted from the abdominal cuticle of males:nonanal, nonanol, nonanoic acid, and (1R*,2S*,5R*,8R*)-iridodial. These compounds were not detected from abdominal cuticle of females. Thoracic extracts of both sexes contained antennal-stimulatory 1-tridecene and EAD-inactive skatole. Chrysopa oculata adults were most sensitive to (1R,2S,5R,8R)-iridodial standard at an EAD-response threshold between 0.1 and 1 pg, which was 10-100 times lower than thresholds for nonanal and nonanoic acid, and up to 10,000 times lower than thresholds for other compounds tested. A similar EAD response pattern was also found in another Chrysopa sp. (Co. quadripunctata Burmeister). In field-trapping experiments, (1R,2S,5R,8R)-iridodial was the only male-specific compound that attracted Co. oculata males. Males also were weakly attracted to (1R,4aS,7S,7aR)-nepetalactol (an aphid sex pheromone component), probably due to the 5% (1R,2S,5R,8R)-iridodial present in the synthetic sample as an impurity. A herbivore-induced plant volatile, methyl salicylate, increased attraction of males to (1R,2S,5R,8R)-iridodial, whereas 1-tridecene was antagonistic. No females were caught in the entire study. Scanning electron micrographs revealed numerous male-specific, elliptical epidermal glands on the 3rd-8th abdominal sternites of Co. oculata, which are likely the pheromone glands. Another lacewing species, Chrysoperla rufilabris (Burmeister) (Cl. = Chrysoperla), did not produce male-specific volatiles or possess the type of gland presumed to produce pheromone in Co. oculata males, but (Z)-4-tridecene was identified as a major antennal-stimulatory compound from thoracic extracts of both sexes of Cl. rufilabris. Thus, (1R,2S,5R,8R)-iridodial (or its enantiomer) is now identified as a male-produced male aggregation pheromone for Co. oculata, the first pheromone identified for lacewings.     

Structures,absolute configurations,and syntheses of volatile signals from three sympatric ant-lion species,Euroleon nostras,Grocus bore,andMyrmeleon formicarius (Neuroptera: Myrmeleontidae)

The thoracic gland of the ant-lionEuroleon nostras was found to contain nerol oxide (1a) and (Z)-6-undecen-2-ol (nostrenol,3) while the speciesGrocus bore contained 10-homonerol oxide (1b) and nostrenol (3). Nerol (2a) and 10-homonerol (2b) were found in a third species,Myrmeleon formicarius. 10-Homonerol, racemic 10-homonerol oxide, and racemic as well as (R)- and (S)-nostrenol were synthesized. The nerol oxide ofE. nostras and the 10-homonerol oxide ofG. bore were found to be racemic, while both species contained optically pure (R)-nostrenol (28).Visiting research scientists from Institute of Photographic Chemistry, Academia Sinica, Beijing, China (H. H.-Z.) and Shanghai Institute of Organic Chemistry, Academia Sinica, 345 Ling Lu, Shanghai, China (L. G.-Q.).     

Identification of (Z)-4-tridecene from Defensive Secretion of Green Lacewing, Chrysoperla carnea

We report the identification of a defensive secretion from the green lacewing, Chrysoperla carnea. By using combined gas chromatography–electroantennographic detection (GC-EAD), we found one major compound in the solvent extract of this secretion that elicited a significant EAD response from the antenna. Based upon its characteristic fragments from gas chromatography–mass spectrometry (GC-MS) analysis, the compound was identified as a tridecene. Dimethyldisulfide derivatization suggested that a double bond was located between positions 4 and 5 in the carbon chain. Thus, the compound was tentatively identified as a 4-tridecene. Coinjection of the extract with a mixture of the Z or E form of the synthetic 4-tridecene revealed that the unknown was (Z)-4-tridecene. EAG dose–responses showed a direct correlation to dose. Single sensillum recordings from sensilla trichodea situated on the antennae suggested the presence of receptor neurons specifically responding to this compound. An arrestment behavior was observed when tested in the Y-tube olfactometer. Preliminary field trapping results indicate that the compound is an antagonist to attraction. The avoidance behavior of predatory ants, observed when tested with the synthetic compound of this secretion further suggested a defensive function.