Broadcasts of wing-fanning vibrations recorded from calling male Ceratitis capitata (Diptera: Tephritidae) increase captures of females in traps.

Female Mediterranean fruit flies, Ceratitis capitata (Wiedemann), from the sterile-male rearing facility in El Pino, Guatemala, were exposed to broadcasts of wing-fanning vibrations recorded from males engaged in calling behavior to investigate the feasibility of developing a female-selective acoustic trap. The recorded signals had frequent amplitude fluctuations and peak frequencies approximately 350 Hz, typical of signals observed in previous studies of Mediterranean fruit fly acoustic behavior. Females did not exhibit long-distance phonotaxis, but remained near a speaker significantly longer when the sounds were broadcast at 103-107 dB than when the speaker was silent. In addition, significantly higher percentages of females were captured by yellow adhesive traps next to a broadcasting speaker than by traps next to a silent mimic. Additional bioassays were conducted with synthetic, 350-Hz tones produced by a thermoacoustic tube as well as with silent mimics of the different sound sources to examine the relative responsiveness of female Mediterranean fruit flies to traps with different acoustic and visual features. The visual attributes of the different sound source assemblies significantly affected capture rates. The range over which the broadcast significantly increased the percentage of female captures was <0.5 m, which may limit the utility of these acoustic cues in large-scale trapping programs. However, the findings of this study do justify further testing of whether optimized short-range acoustic signals could be used to augment longer range pheromonal and visual cues to improve the efficacy of female-selective traps.

Early detection and population monitoring of Ceratitis capitata (Diptera: Tephritidae) in a mixed-fruit orchard in northern Greece.

Population monitoring of the Mediterranean fruit fly,Ceratitis capitata (Wiedemann), was studied in 1998 in a mixed-fruit orchard in northern Greece, using International Pheromone McPhail traps (IPMT) baited with the female targeted attractants ammonium acetate, putrescine, and trimethylamine, and Jackson traps baited with the male specific parapheromone trimedlure. Special emphasis was placed on detecting the low initial adult population resulting from surviving overwintering larvae as early as possible in the spring and early summer. Traps were suspended on various host trees, using trap grid densities of either 15 or 1.5 traps per hectare. The first adults detected were females captured on 24 June in IPMT traps suspended on apricot trees, which are among the earliest maturing hosts in the area. From the end of July, the most effective trap was the IPMT trap placed on peaches, which followed apricots in the fruit ripening sequence. IPMT traps captured predominately females (approximately 80% of the total captures) and by far outperformed Jackson traps in early detection (the first males in Jackson traps were captured in August) as well as in total captures until mid-October. After mid-October, however, more flies were captured in Jackson traps. Comparing the performance of two trap grid densities on apple trees (the common host in the two grids), we found that in the high-density trap grid the first adults were detected 1 wk earlier than in the low-density trap grid. Our findings for this locality suggest that trap type and plant species on which traps are suspended are of key importance in early detection and population monitoring of C. capitata.

Attraction of adult Rhagoletis indifferens (Diptera: Tephritidae) to unbaited and odor-baited red spheres and yellow rectangles.

Five sizes of red spheres (4, 6, 8, 10, and 12 cm diameter) and 2 orientations of yellow rectangles (vertical and V) were evaluated as unbaited sticky-coated traps for western cherry fruit flies, Rhagoletis indifferens Curran, in unmanaged cherry trees in Washington and Oregon. Red spheres that were 10 cm in diameter attracted more flies than red spheres that were 8 or 12 cm in diameter and significantly more flies than 4- or 6-cm spheres and yellow rectangles of either orientation. In a 2nd test, red spheres (10 cm diameter) baited with ammonium carbonate alone or ammonium carbonate plus putrescine attracted significantly more R. indifferens than similar spheres baited with ammonium acetate alone, putrescine alone, 3-methyl-1-butanol alone, or combinations of these substances. In a 3rd test, vertical yellow rectangles baited with ammonium carbonate alone attracted numerically more R. indifferens than any of the aforementioned substances alone or in combination. We discuss the potential value of 10-cm red spheres baited with ammonium carbonate for monitoring and direct control of R. indifferens.

Analysis and quantitation of insect juvenile hormones using chemical ionization ion-trap mass spectrometry.

A method for identification and quantitation of insect juvenile hormones (JH) has been developed using capillary gas chromatography-chemical ionization (isobutane)-ion-trap mass spectroscopy. The method does not require derivatization of samples or use of selected ion monitoring. Analysis over a mass range of 60-350 u allowed for identification of as little as 0.01 pmol of individual JH homologs. Quantitative analysis was based on the ion intensities of six diagnostic ions and the summed intensities of these ions for each homolog. The ratio of diagnostic ions did not vary significantly over a range of concentrations from 2.7 to 200 pg. The technique was used to identify and quantify the amounts of JH homologs secreted by individual retrocerebral complexes from the moth Manduca sexta maintained in tissue culture and to identify JH III from hexane extracts of hemolymph of the Caribbean fruit fly. No discrimination due to disparate abundance ratios of the individual homologs was found when analyzing natural product samples differing in concentration by at least fivefold. The technique allows for facile, concrete identification and quantitation of biologically relevant amounts of JH. The ability to analyze samples without derivatization or fractionation by chromatographic methods, coupled with data acquisition over a broad mass range, provides levels of accuracy and confidence greater than those of other methods.

Blind identification of multichannel FIR blurs and perfect image restoration.

Despite its practical importance in image processing and computer vision, blind blur identification and blind image restoration have so far been addressed under restrictive assumptions such as all-pole stationary image models blurred by zero or minimum-phase point-spread functions. Relying upon diversity (availability of a sufficient number of multiple blurred images), we develop blind FIR blur identification and order determination schemes. Apart from a minimal persistence of the excitation condition (also present with nonblind setups), the inaccessible input image is allowed to be deterministic or random and of unknown color of distribution. With the blurs satisfying a certain co-primeness condition in addition, we establish existence and uniqueness results which guarantee that single input/multiple-output FIR blurred images can be restored blindly, though perfectly in the absence of noise, using linear FIR filters. Results of simulations employing the blind order determination, blind blur identification, and blind image restoration algorithms are presented. When the SNR is high, direct image restoration is found to yield better results than indirect image restoration which employs the estimated blurs. In low SNR, indirect image restoration performs well while the direct restoration results vary with the delay but improve with larger equalizer orders.

Mapping of the target antigens of the rotavirus-specific cytotoxic T cell response.

The cytotoxic T cell (CTL) response in C57/B16 (H-2b) mice to rotavirus has been analysed using a cognate set of vaccinia virus recombinants covering the 12 primary gene products of the UKtc strain of bovine rotavirus. The gene products of RNA segments 5 (VP5/NSP-1) and 8 (VP7) both elicited a classic CD8+ Class I MHC restricted CTL response. Using L cells transfected with specific Class I MHC loci as targets the VP5/NSP-1 response was found to be restricted at Db and the VP7 response at Kb. Vaccinia virus recombinants expressing VP7 genes from seven G serotypes were used to show that the CTL response to this antigen is completely cross-reactive. By contrast, using the same strategy the CTL response to VP5/NSP-1 was found to be virus strain specific. A vaccinia virus recombinant carrying RNA segment 5 from the deletion mutant P9D delta 5 was used to localize at least one CTL epitope in VP5/ NSP-1 to the first 150 amino acids of the protein. The expression of a number of fragments of VP7 in vaccinia virus recombinants was used to show that the CTL epitope (amino acids 31-40) previously identified through the use of synthetic peptides is virus serotype specific rather than cross-reactive.

Volatile Semiochemicals Released from Undamaged Cotton Leaves (A Systemic Response of Living Plants to Caterpillar Damage).

Cotton plants (Gossypium hirsutum L.), attacked by herbivorous insects release volatile semiochemicals (chemical signals) that attract natural enemies of the herbivores to the damaged plants. We found chemical evidence that volatiles are released not only at the damaged site but from the entire cotton plant. The release of volatiles was detected from upper, undamaged leaves after 2 to 3 d of continuous larval damage on lower leaves of the same plant. Compounds released systemically were (Z)-3-hexenyl acetate, (E)-[beta]-ocimene, linalool, (E)-4,8-dimethyl-1,3,7-nonatriene, (E)-[beta]-farnesene, (E,E)-[alpha]-farnesene, and (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene. All systemically released compounds are known to be induced by caterpillar damage and are not released in significant amounts by undamaged plants. Other compounds, specifically indole, isomeric hexenyl butyrates, and 2-methylbutyrates, known to be released by cotton in response to caterpillar damage, were not released systemically. However, when upper, undamaged leaves of a caterpillar-damaged plant were damaged with a razor blade, they released isomeric hexenyl butyrates, 2-methylbutyrates, and large amounts of constitutive compounds in addition to the previously detected induced compounds. Control plants, damaged with a razor blade in the same way, did not release isomeric hexenyl butyrates or 2-methylbutyrates and released significantly smaller amounts of constitutive compounds. Indole was not released systemically, even after artificial damage.

A system and methodology for measuring volatile organic compounds produced by hydroponic lettuce in a controlled environment.

A system and methodology were developed for the nondestructive qualitative and quantitative analysis of volatile emissions from hydroponically grown 'Waldmann's Green' leaf lettuce (Lactuca sativa L.). Photosynthetic photon flux (PPF), photoperiod, and temperature were automatically controlled and monitored in a growth chamber modified for the collection of plant volatiles. The lipoxygenase pathway products (Z)-3-hexenal, (Z)-3-hexenol, and (Z)-3-hexenyl acetate were emitted by lettuce plants after the transition from the light period to the dark period. The volatile collection system developed in this study enabled measurements of volatiles emitted by intact plants, from planting to harvest, under controlled environmental conditions.

Photosynthetic photon flux, photoperiod, and temperature effects on emissions of (Z)-3-hexenal, (Z)-3-hexenol, and (Z)-3-hexenyl acetate from lettuce.

To investigate the effects of environment on plant volatile emissions, 'Waldmann's Green' leaf lettuce was cultivated under different levels of photosynthetic photon flux (PPF), photoperiod, and temperature. A modified growth chamber was used to sample plant volatile emissions nondestructively, over time, and under controlled conditions. Total volatile emission rates were significantly higher from lettuce cultivated under PPF of 360 or 200 micromoles m-2 s-1 compared to 105 micromoles m-2 s-1, and significantly higher under a 16-h photoperiod than an 8-h photoperiod. No differences were detected among emission rates from different temperature treatments. In controlled environments, emissions could be regulated by adjusting environmental conditions accordingly.

Quadrupole storage mass spectrometry of mono- and dimethylalkanes.

Monomethyl and dimethylalkanes with one, two, three, four, five, and seven methylene groups separating the methyl branches were synthesized and analyzed by magnetic sector and quadrupole storage (ion trap) mass spectrometry. The spectra produced by the magnetic sector instrument were in good agreement with previously reported data, whereas the ion trap spectrometer produced ions resulting from cleavages adjacent to the branching points, markedly different than those from the magnetic sector instrument. Fragmentation patterns show that the ion trap mass spectrometer can be used to characterize branched alkanes in nanogram and subnanogram quantities.

Production and release of (Z,E)-9,12-tetradecadienal by sex pheromone glands of females ofPlodia interpunctella (lepidoptera: pyralidae).

Extracts of sex pheromone glands obtained from females ofPloida interpunctella contained detectable amounts of (Z,E,)-9,12-tetradecadien-1-ol acetate (Z9,E12-14:Ac) and (Z,E.)-9,12-tetradecadien-1-ol (Z9,E12-14:OH) 4 hr prior to the first scotophase after adult emergence. The amount of pheromone increased during the first 4 hr of the scotophase and then declined to low levels during the subsequent photophase. Decapitation of females immediately after emergence, prior to expansion of the wings, inhibited production of pheromone during the subsequent 48 hr. Injection of extracts of the heads of 1-day-old females ofP. interpunctella of partially purified extracts of the cephalic ganglia of females of the corn earworm moth into decapitated females stimulated production of bothZ9,E12-14:Ac andZ9,E12-14:OH as well as production of (Z,E)-9,12-tetradecadienal (Z9,E12-14:Al). This aldehyde was subsequently identified from extracts of pheromone glands obtained from naturally calling females as well as from volatiles emitted by calling females. Studies on the terminal steps in biosynthesis of the pheromone showed thatZ9,E12-14:OH was produced from the corresponding acetate and thatZ9,E12-14:Al was produced from the alcohol via the action of an oxidase(s).

Volatiles emitted by different cotton varieties damaged by feeding beet armyworm larvae.

Volatile compounds elicited by insect herbivore feeding damage in five cotton cultivars and one naturalized cotton variety were examined by allowing beet armyworm larvae to feed overnight on leaves and collecting volatiles from the plants in situ. Of 23 compounds identified from larval damaged leaves, terpenes and lipoxygenase-hydroperoxide lyase-derived volatiles predominated. No pronounced differences in the levels of volatile emission were noted from leaves of undamaged plants of the different varieties. However, average volatile emission from damaged leaves of the naturalized variety was almost sevenfold higher than from damaged leaves of the commercial cultivars. This was despite the fact that larvae preferred feeding on the leaves of commercial cultivars over those of the naturalized variety in choice tests.

Diurnal cycle of emission of induced volatile terpenoids by herbivore-injured cotton plant.

Cotton plants attacked by herbivorous insect pests emit relatively large amounts of characteristic volatile terpenoids that have been implicated in the attraction of natural enemies of the herbivores. However, the composition of the blend of volatile terpenes released by the plants varies remarkably throughout the photoperiod. Some components are emitted in at least 10-fold greater quantities during the photophase than during the scotophase, whereas others are released continuously, without conforming to a pattern, during the entire time that the plants are under herbivore attack. The diurnal pattern of emission of volatile terpenoids was determined by collecting and analyzing the volatile compounds emitted by cotton plants subjected to feeding damage by beet armyworm larvae in situ. The damage was allowed to proceed for 3 days, and volatile emission was monitored continuously. During early stages of damage high levels of lipoxygenase-derived volatile compounds [e.g., (Z)-3-hexenal, (Z)-3-hexenyl acetate] and several terpene hydrocarbons [e.g., alpha-pinene, caryophyllene] were emitted. As damage proceeded, high levels of other terpenes, all acyclic [e.g., (E)-beta-ocimene, (E)-beta-farnesene], were emitted in a pronounced diurnal fashion; maximal emissions occurred in the afternoon. These acyclic terpenes followed this diurnal pattern of emission, even after removal of the caterpillars, although emission was in somewhat smaller amounts. In contrast, the emission of cyclic terpenes almost ceased after the caterpillars were removed.

Effects of host plant,Gossypium hirsutum L., on sexual attraction of cabbage looper moths,Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae).

Unmated female or male cabbage looper moths,Trichoplusia ni (Hübner), were attracted more often in a flight tunnel to a cage with moths of the opposite sex and a bouquet of cotton foliage. Increased sexual attractiveness of females with plants may be a result of stimulation of pheromone release in response to plant odor, since more males were attracted when odor of cotton foliage was passed over females than when odor of females was passed over cotton foliage before venting into the flight tunnel. Increased sexual attractiveness of males with plants is due in part to host odor enhancement of female attraction to male pheromone, since more females were attracted to synthetic male pheromone (a blend of enantiomers of linalool and isomers of cresol) and a cotton leaf extract than were attracted to male pheromone alone. A short synthesis procedure was developed for (S)-(+)-linalool, the major component of the male sex pheromone, isolated from hair pencils, used in these tests.

An automated system for use in collecting volatile chemicals released from plants.

A system is described for the collection of volatiles produced by plants that minimizes stress on the plant in an environment that is free from chemical impurities. Air entering a volatile collection chamber containing a plant is purified using a nonwoven fabric media infused with charcoal. A multitasking, computer-automated system is described that can simultaneously collect volatilized chemicals from plants as well as monitor and record environmental conditions associated with those collections. Collection of up to 16 samples can be made in varying sampling order, flow rates, and user-specified time periods, without disturbing the sampling environment. During the same time period, this system is capable of simultaneously monitoring up to eight environmental parameters using any type of sensor with electrical signal outputs. A multiport base assembly was designed to fit around the base of the plant permitting air samples to be collected at the bottom of the chamber. The chamber can pass ambient light so the plant may follow its natural photocycles. The entire system can be configured for continuous laboratory duty or portable field use by utilizing components that run on DC voltages. For the purpose of testing the system's performance, we determined the periodicity of the release of volatiles from red and yellow flowering four o'clock plants,Mirabilis jalaba (Nyctaginaceae). The major chemical released from four o'clocks was identified as ocimene. The onset of release occurred between 1400 and 1600 hr and increased with time with maximum amount of ocimene released during 1800-2000 hr, followed by a decrease in emission. No ocimene was detected after 2400 hr. Determination of the amount of ocimene released per flower was calculated for the 1800- to 2000-hr time period. Based on the number of open flowers during the 1800- to 2000-hr period, yellow four o'clock's released 80.9 (±7.3 SD) ng/hr/flower, while the red flowers released 51.9 (±7.0 SD) ng/hr/flower.

A bioassay system for collecting volatiles while simultaneously attracting tephritid fruit flies.

A bioassay system was developed that permits the testing of various substrates for biological activity in a flight tunnel, while simultaneously collecting a portion of the volatiles from the attractive source for subsequent chemical identification and quantification. Bioassays of the response of virgin female Caribbean fruit flies,Anastrepha suspensa (Loew) (Diptera: Tephritidae), to volatiles released by calling males were conducted in a greenhouse under natural light cycles and fluctuating environmental conditions, similar to those in the field. Using this system, the periodicity of response of the female flies between 1300 and 1845 hr (EST) was tested. Fifty to 75% response occurred between 1700 and 1845 hr. Male pheromone release was greatest between 1500 and 1800 hr. Videotaped records of insects, taken between 1700 and 1800 hr as flies approached and entered the traps, were analyzed to interpret the communicative role of the volatiles released. Significantly more flies landed on and entered the pheromone-emitting trap than the control trap. There was no difference in the amount of time spent on the trap face, an indication that volatiles were attractants. The system described should be of general utility in determination of the attraction of pest fruit flies to suspected attractants.

NMR spectral assignment of lactone pheromone components emitted by Caribbean and Mexican fruit flies.

By utilizing one- and two-dimensional nuclear magnetic resonance techniques, the complete assignments of the proton and carbon spectra of the lactones anastrephin, epianastrephin, and suspensolide have been accomplished. These compounds are pheromone components for both the Caribbean and Mexican fruit flies. The relative stereochemistries of anastrephin and epianastrephin were demonstrated by nuclear Overhauser difference spectroscopy. With complete spectral assignments now available, biosynthesis of these molecules may be studied by feeding specific isotopically labeled nutrients to flies and subsequently analyzing the volatiles produced for the presence and position of the labelling isotope.

Development and evaluation of systems to collect volatile semiochemicals from insects and plants using a charcoal-infused medium for air purification.

A system is described for the collection of volatiles produced by plants and insects that minimizes stresses on the plant or insect in an environment that is free from chemical impurities. Air entering a volatile collection chamber containing insects and/or plants was purified using a nonwoven fabric medium infused with charcoal. When three layers of this material were used, the total amount of impurities detected by gas chromatography was less than 40 ng/hr at a collection rate of 1 L/min. The air filtration system can maintain this level of air purification for 96 hr at an air flow of 0.43 m/sec, or a total volume of approximately 750,000 L of air. The air filtration system did not alter the relative humidity of the purified air compared to the relative humidity of ambient air. A multiport collector system was developed for use with the insect volatile collection system and enabled up to three samples to be collected without disturbing the system.

An equilibrium and stability study of Δ(1)-pyrroline.

Several properties of the compound 3,4-dihydro-2H-pyrrole(A1-pyrroline), which has been reported as a component of the male-produced Mediterranean fruit fly pheromone, have been determined by [(1)H]- and [(13)C]nuclear magnetic resonance spectroscopy. The stability of Δ(1)-pyrroline in several solvents and at moderately elevated temperatures has been investigated, and it has been established that it exists as both a monomer and trimer in solution. Although equilibrium studies indicate that the trimer is thermodynamically more stable than the monomer in solution, only the monomer was found in the vapor phase based on infrared analysis.

Identification of male cabbage looper sex pheromone attractive to females.

A multicomponent pheromone produced by male cabbage looper moths that is attractive to female moths in a flight tunnel bioassay was isolated and identified. Based on analyses of hairpencil extracts of male cabbage loopers and volatiles emitted by males, the pheromone has been identified as a blend consisting of (S)-(+)-linalool,p-cresol, andm-cresol. The chirality of the major component, (S)-(+)-linalool, is important for behavioral response of females. These pheromonal compounds were also identified as volatiles released by males when males were exposed to the principal pheromone component of female cabbage loopers, (Z)-7-dodecen-1-ol acetate. The amount of male pheromone released was increased significantly when males were exposed to a combination of (Z)-7-dodecen-1-ol acetate and the odor from cabbage. Neither linalool nor the cresols were detected in volatiles from cabbage or from males exposed to cabbage odor.