Characterization of Z/E11- and Z9-desaturases from the obliquebanded leafroller moth, Choristoneura rosaceana

A ▵11-desaturase gene was cloned from the sex pheromone gland of the obliquebanded leafroller moth, Choristoneura rosaceana. The desaturase cDNA sequence spans 1300 nucleotides with an open reading frame encoding a 335 amino-acid protein, which has 81% identity to a Z/E11-desaturase of the redbanded leafroller moth, Argyrotaenia velutinana. A functional assay with a pYES2 yeast expression system demonstrated that the ▵11-desaturase exhibits unusual substrate and stereospecificities in producing a Z/E11 mixture (7:1) of only C14 acids. A metabolic Z9-desaturase also was cloned from fat body of this species, and proved to be in the class that produces more Z9-16:Acid than Z9-18:Acid

Temporal and Spatial Distribution of the Oriental Beetle (Coleoptera: Scarabaeidae) in a Golf Course Environment

The mating season of the oriental beetle, Exomala orientalis (Waterhouse), in 1994 and 1995 at Bethpage State Park, Farmingdale, NY (40° 45′ N, 73° 28′ W) began in the middle of June, peaked in the 1st wk of July, and ended in the middle of August. There were differences in the emergence schedule among fairways as well as local differences between roughs and fairway. Both sexes were most active around sunset on shorter-cut turf (i.e., fairways, greens, and tees, versus roughs), and the few individuals seen during the daylight hours were mostly males. These males were generally found perched on vegetation at the border of the fairway. Feeding was not observed, except on flowers by females devoid of mature eggs. This study confirms our observations on the pattern of activity in an earlier study conducted with the use of synthetic pheromone traps. It also explains the difficulty encountered by earlier workers in finding adults of this insect in the field. Implications of the above findings on the management of the oriental beetle are discusse

Purification, Identification, Concentration and Bioactivity of (Z)-7-Dodecen-1-yl Acetate: Sex Pheromone of the Female Asian Elephant, Elephas maximus

In their natural ecosystems, adult male and female Asian elephants, Elephas maximus, live separately. For several weeks prior to ovulation, female elephants release a substance in their urine which elicits a high frequency of non-habituating chemosensory responses, especially flehmen responses, from male elephants. These responses occur prior to, and are an integral part of, mating. Using bioassay-guided fractionation, quantitatively dependent on these chemosensory responses, a specific sex pheromone was isolated and purified by an alternating series of organic and/or aqueous extractions, column chromatography, gas chromatography and high-performance liquid chromatography. Using primarily 1H-proton nuclear magnetic resonance (NMR) spectrometry and gas chromatography-mass spectrometry (GC-MS) of the urine-derived pheromone and its dimethyl disulfide derivative, we determined the structure of the active compound to be (Z)-7-dodecen-1-yl acetate (Z7-12:Ac). Concentrations of Z7-12:Ac in the female urine increased from non-detectable during the luteal phase to 0.48μg/ml (0.002 mM) early in the follicular phase and to 33.0μg/ml (0.146 mM) just prior to ovulation. Bioassays with commercially available authentic synthetic Z7-12:Ac, using 10 Asian male elephants at several locations in the US, demonstrated quantitatively elevated chemosensory responses that were robust during successive tests, and several mating-associated behaviors. Bioassays with Z7-12:Ac with adult male elephants dwelling in more natural social situations in forest camps in Myanmar revealed some differing contextual pre-mating behavioral components. The remarkable convergent evolution of this compound suggests that compounds identified in mammalian exudates that are also present in pheromone blends of insects should be re-evaluated as potential mammalian chemosignals. Chem. Senses 22: 417-437, 199

Identification of the Sex Pheromone of the Webbing Coneworm Moth, Dioryctria disclusa (Lepidoptera: Pyralidae)

A sex pheromone component for the webbing coneworm, Dioryctria disclusa, has been identified as (Z)-9-tetradecenyl acetate. Traps baited with rubber septa impregnated with this compound at loadings of 30 to 300 μg caught the same as or significantly better than traps baited with two virgin female moths. Addition of 3 to 30% of the E isomer did not increase trap catch, and only (Z)-9-tetradecenyl acetate was found in the female extrac

Gene Flow Among Three Races of European Corn Borers (Lepidoptera: Pyralidae) in New York State

In New York state, there are three races of European corn borer moths, which are characterized principally by differences in voltinism and the sex pheromone communication system. One race is bivoltine, with females producing and males responding to a 99:1 E/Z isomeric ratio of ∆11-14:0Ac's as the sex pheromone. Two races, one univoltine and one bivoltine, produce and respond to a 3:97 E/Z blend of ∆11-14:OAc's. The races are referred to as BE, UZ, and BZ to denote these differences. Analyses by gas chromatography of field-collected females indicate that there is significant hybridization between the Z and E races when in sympatry, with hybrid females producing a 68:32 ratio of E/Z11-14:OAc. Gene flow among the races was investigated using differences in triose phosphate isomerase (TPI) allozyme frequencies of moths from sites sampled across the state. The fixed nature of the Tpi-1 allele in the BE race and increases in the Tpi-1 allele frequencies in UZ populations in sympatry with the BE race support the hypothesis that gene flow following hybridization is unidirectional from BE populations into the Z populations. In addition, the TPI genotypes of the 10 hybrid females analyzed were consistent with hybridization occurring by E males mating with Z female

Comparing Peripheral Olfactory Coding with Host Preference in the Rhagoletis Species Complex

Recent studies have shown that flies from sympatric populations of Rhagoletis pomonella infesting hawthorn, apple, and flowering dogwood fruit can distinguish among unique volatile blends identified from each host. Analysis of peripheral chemoreception in Rhagoletis flies suggests that changes in receptor specificity and/or receptor neuron sensitivity could impact olfactory preference among the host populations and their hybrids. In an attempt to validate these claims, we have combined flight tunnel analyses and single sensillum electrophysiology in F2 and backcross hybrids displaying a variety of behavioral phenotypes. Results show that differences in peripheral chemoreception among second-generation adults do not provide a direct correlation between peripheral coding and olfactory behavior. We conclude that either the plasticity of the central nervous system in Rhagoletis can compensate for significant alterations in peripheral coding or that peripheral changes present subtle effects on behavior not easily detectable with current techniques. The results of this study imply that the basis for olfactory behavior in Rhagoletis has a complicated genetic and neuronal basis, even for populations with a recent divergence in preferenc

Sex Pheromone Responses of the Oriental Beetle (Coleoptera: Scarabaeidae)

The synthetic female sex pheromone of the oriental beetle, Anomala orientalis Waterhouse, was evaluated in the field and in a sustained-flight tunnel. In a 2-wk period, > 150,000 beetles were captured on three golf course fairways in Connecticut. Contrary to earlier reports that these beetles are most active during the warm, sunny portions of the day, we observed that peak activity occurs around sunset. Ten micrograms of either (Z)-7-tetradecen-2-one or an 89/11 (Z/E) blend on a rubber septum was found to be the minimum concentration with which no significant decrease in catch was observed in the field. There was no discrimination between Z and the blend at 1 μg and higher concentrations, but the E-isomer alone trapped significantly fewer beetles than either Z alone or the blend. These results are consistent with the flight tunnel data. The effects of temperature and light intensity on the mating behavior of A. orientalis also are discusse

Monitoring Grape Berry Moth (Paralobesia viteana: Lepidoptera) in Commercial Vineyards using a Host Plant Based Synthetic Lure

For some Lepidopteran pests, such as the grape berry moth Paralobesia viteana (Clemens), poor correlation between males captured in traps baited with sex pheromone and oviposition activities of female moths has called into question the value of pheromone-based monitoring for these species. As an alternative, we compared the capture of female and male grape berry moth in panel traps baited with synthetic host volatiles with captures of males in pheromone-baited wing traps over two growing seasons in two blocks of grapes in a commercial vineyard in central New York. Lures formulated in hexane to release either 7-component or 13-component host volatile blends captured significantly more male and female grape berry moth on panel traps compared with the numbers captured on panel traps with hexane-only lures. For both sexes over both years, the same or more moths were captured in panel traps along the forest edge compared with the vineyard edge early in the season but this pattern was reversed by mid-season. Male moths captured in pheromone-baited wing traps also displayed this temporal shift in location. There was a significant positive correlation between captured males and females on panel traps although not between females captured on panel traps and males captured in pheromone-baited traps for both years suggesting pheromone traps do not accurately reflect either female or male activity. Male moths captured in pheromone traps indicated a large peak early in each season corresponding to first flight followed by lower and variable numbers that did not clearly indicate second and third flights. Panel trap data, combining males and females, indicated three distinct flights, with some overlap between the second and third flights. Peak numbers of moths captured on panel traps matched well with predictions of a temperature-based phenology model, especially in 2008. Although effective, panel traps baited with synthetic host lures were time consuming to deploy and maintain and captured relatively few moths making them impractical, in the current design, for commercial purpose

Trapping \u3ci\u3ePhyllophaga \u3c/i\u3espp. (Coleoptera: Scarabaeidae: Melolonthinae) in the United States and Canada using sex attractants.

The sex pheromone of the scarab beetle, Phyllophaga anxia, is a blend of the methyl esters of two amino acids, L-valine and L-isoleucine. A field trapping study was conducted, deploying different blends of the two compounds at 59 locations in the United States and Canada. More than 57,000 males of 61 Phyllophaga species (Coleoptera: Scarabaeidae: Melolonthinae) were captured and identified. Three major findings included: (1) widespread use of the two compounds [of the 147 Phyllophaga (sensu stricto) species found in the United States and Canada, males of nearly 40% were captured]; (2) in most species intraspecific male response to the pheromone blends was stable between years and over geography; and (3) an unusual pheromone polymorphism was described from P. anxia. Populations at some locations were captured with L-valine methyl ester alone, whereas populations at other locations were captured with L-isoleucine methyl ester alone. At additional locations, the L-valine methyl ester-responding populations and the L-isoleucine methyl ester-responding populations were both present, producing a bimodal capture curve. In southeastern Massachusetts and in Rhode Island, in the United States, P. anxia males were captured with blends of L-valine methyl ester and L-isoleucine methyl ester

Eavesdropping on Plant Volatiles by a Specialist Moth: Significance of Ratio and Concentration

We investigated the role that the ratio and concentration of ubiquitous plant volatiles play in providing host specificity for the diet specialist grape berry moth Paralobesia viteana (Clemens) in the process of locating its primary host plant Vitis sp. In the first flight tunnel experiment, using a previously identified attractive blend with seven common but essential components (“optimized blend”), we found that doubling the amount of six compounds singly [(E)- & (Z)-linalool oxides, nonanal, decanal, β-caryophyllene, or germacrene-D], while keeping the concentration of other compounds constant, significantly reduced female attraction (average 76% full and 59% partial upwind flight reduction) to the synthetic blends. However, doubling (E)-4,8-dimethyl 1,3,7-nonatriene had no effect on female response. In the second experiment, we manipulated the volatile profile more naturally by exposing clonal grapevines to Japanese beetle feeding. In the flight tunnel, foliar damage significantly reduced female landing on grape shoots by 72% and full upwind flight by 24%. The reduction was associated with two changes: (1) more than a two-fold increase in total amount of the seven essential volatile compounds, and (2) changes in their relative ratios. Compared to the optimized blend, synthetic blends mimicking the volatile ratio emitted by damaged grapevines resulted in an average of 87% and 32% reduction in full and partial upwind orientation, respectively, and the level of reduction was similar at both high and low doses. Taken together, these results demonstrate that the specificity of a ubiquitous volatile blend is determined, in part, by the ratio of key volatile compounds for this diet specialist. However, P. viteana was also able to accommodate significant variation in the ratio of some compounds as well as the concentration of the overall mixture. Such plasticity may be critical for phytophagous insects to successfully eavesdrop on variable host plant volatile signals