Age-related response of male melon fliesDacus cucurbitae (Diptera: Tephritidae) to cue-lure

Laboratory-reared and wild adults of the melon fly,Dacus cucurbitae Coquillett, were tested for response to cue-lure at various ages. Virgin laboratory (4, 6, 8, 10, 12, and 14 days old) and wild (10, 12, 14, 16, 18, 20, and 22 days old) flies were released into outdoor field cages and trapped from 0800 until 1600 hr. Response of males to cue-lure increased with age and corresponded with sexual maturity for each strain. Females of both strains were relatively nonresponsive to cue-lure. Failure to eradicate in past male annihilation programs againstD. cucurbitae may be explained in part by the fact that only older males, which may have already mated with gravid females, respond to cue-lure.     

Synthesis of attractants for oriental fruit flyDacus dorsalis Hendel using a catalytic organocopper coupling reaction

A general synthetic approach to various catechol derivatives was developed using a copper-catalyzed cross-coupling reaction of 1,2-dimethoxy-4-brornomethyl, 1-ethoxy-2-methoxy-4-bromomethyl- and 2-ethoxy-1-methoxy-4-bromomethylbenzenes with Grignard reagents. Dilithium tetrachlorocuprate was an acceptable catalyst in the dimethoxy series, whereas copper(I) iodide in THF-HMPA was a superior catalyst in all cases due to decreased side reactions, i.e., reduction and reductive coupling. Methyl-substituted analogs of methyl eugenol, a potent attractant of Oriental fruit fly,Dacus dorsalis Hendel, were synthesized by this method and evaluated for attractancy in field tests.On leave from the Institute of Organic Chemistry of the Armenian Academy of Sciences, Yerevan, Armenia; author to whom correspondence should be addressed.Presented at the 204th ACS National Meeting, Washington, D.C., 1992. This paper reports the results of research only. Mention of a proprietory product does not constitute an endorsement of this product by the USDA.     

Trimedlure enantiomers: Differences in attraction for mediterranean fruit fly,Ceratitis capitata (Wied.) (Diptera: Tephritidae)

The most biologically active enantiomer of trimedlure, a synthetic lure attractive to male Mediterranean fruit flies, is the 1S,2S,4R enantiomer of isomer C, the fert-butyl ester of ris-4-chloro-trans-2-methylcyclohexanecarboxylic acid. We also determined that the 1R,2R,5S enantiomer of isomer A is significantly more attractive than its optical antipode. Essential differences in the current synthetic work that are critical to possible commercialization of this preparation are detailed herein.Deceased.     

Residual activity of oviposition-deterring pheromone inRhagoletis pomonella (Diptera: Tephritidae) and female response to infested fruit

Under dry conditions, oviposition-deterring pheromone (ODP) of the apple maggot fly (Rhagoletis pomonella Walsh) on host fruit proved deterrent to ovipositing females for at least three weeks, with a half-life of ca. 11 days. There was no difference in decline of residual activity under lab vs. field conditions or between fly-deposited ODP vs. an application of a water extract of ODP. A decline in pheromone activity resulted from exposure to both natural and simulated rainfall. For natural rainfall, greatest losses (50– 61%) in activity resulted from high-intensity rains, with substantially less activity lost (13–35%) following light or moderate intensity rains.R. pomonella females discriminated against fruit without ODP but with conspecific larvae. Discrimination against infested fruit was manifested within fewer days following infestation of small fruit (9 mm diam.) as compared to larger fruit (15 mm diam.).     

A four-component attractant for the mexican fruit fly,Anastrepha ludens (Diptera: Tephritidae), from host fruit

Sixteen chemicals found in fermented chapote fruit odor were evaluated as attractants for hungry adult Mexican fruit flies. Ethyl octanoate, ethyl benzoate, terpinyl acetate, ethyl salicylate, and (–)--copaene proved slightly attractive. Several of the chemicals also were tested for their ability to increase the attractiveness of the previously developed chapote-derived attractant (CEH) consisting of 1,8-cineole, ethyl hexanoate, and hexanol. Combinations containing CEH with ethyl octanoate, ethyl benzoate, 4-terpineol, (–)--cubebene, or-terpineol were significantly more attractive than CEH alone. The two most attractive four-component combinations were ethyl octanoate with CEH (CEHO) and ethyl benzoate with CEH. No combinations containing greater numbers of chemicals were significantly more attractive than CEHO. Therefore, CEHO was selected for further study in this paper. Of CEHO component ratios that were tested, the most attractive was 1011100 for the chemicals 1,8-cineole, ethyl hexanoate, hexanol, and ethyl octanoate, respectively. Formulations of CEHO into rubber septa and polyvinyl chloride (PVC) were aged 0–15 days and tested againstTorula yeast in competing McPhail traps in a flight chamber. Summed over all lure ages, rubber septa and PVC dispensers, respectively, were 1.2 and 1.5 times more attractive thanTorula yeast. PVC dispensers aged 10–15 days were approximately 2.1 times more attractive thanTorula yeast.     

Isolation,identification, and synthesis of male-produced sex pheromone of papaya fruit fly,Toxotrypana curvicauda Gerstaecker (Diptera: Tephritidae)

A male-produced sex pheromone of the papaya fruit fly,Toxotrypana curvicauda Gerstaecker, was isolated from volatiles collected from air passed over calling males and was identified as 2-methyl-6-vinylpyrazine by comparative gas-liquid chromatographic and spectroscopic evidence. Synthetic 2-methyl-6-vinylpyrazine elicited typical pheromonal responses from unmated mature female flies such as walking, running, and flying in an arena bioassay; flying upwind with a zigzag flight pattern; and hovering in the pheromone plume in a wind-tunnel bioassay. These responses were similar quantitatively and qualitatively to responses to naturally occurring pheromone from calling male papaya fruit flies.This article reports the results of research only. Mention of a proprietary product does not constitute an endorsement or the recommendation for its use by USDA.     

Caribbean fruit fly,Anastrepha suspensa (Loew), attraction to host fruit and host kairomones

Extracts of 22 fruits were tested for their attractancy toAnastrepha suspensa (Loew), the Caribbean fruit fly. Box-orange, calamondin, carambola, cattley guava, loquat, and Surinam-cherry were about equal in attractiveness to males and females. Nine synthetic chemicals, including four found in box-orange ripe seed, were attractive to females. Five synthetic chemicals, including two in box-orange ripe seed, were attractive to males. Farnesol,-phellandrene, and 3-carene were highest in attractiveness to both males and females. Females were more attracted than males to 12 synthetic chemicals. These data suggest that host chemicals serve as attractants and that female and male specific attractants and traps could be developed from host kairomone data. These data also suggest that the volatilization of chemicals from water may play an important role in kairomone biology.     

Biology of pheromone release by male caribbean fruit flies,Anastrepha suspensa (Diptera: Tephritidae)

Males of the Caribbean fruit fly,Anastrepha suspensa (Loew), typically form leks and attract females by releasing a multicomponent volatile pheromone. Previous reports have identified two nine-carbon alcohols, three lactones, a sesquiterpene, and a monoterpene in the volatiles. The present report is a study of the physiology of male pheromone release and of ecological and social interactions that influence pheromone release by laboratoryreared flies. Volatiles released by males were trapped on Tenax, eluted, separated, and quantitatively measured by gas chromatography. Experiments showed that the volatiles were primarily released from mouth and anus. Sealing the anal opening or the mouth with melted beeswax resulted in up to 40% or greater reduction in most components, and sealing both mouth and anus further reduced release of volatiles, but some volatiles are possibly still released directly from the cuticle. An anal pouch of everted tissue played a major role as a large evaporative surface for release of some of the volatile components. Male flies entrained to a 1410 light-dark cycle showed a peak release of volatiles at 11–12 hr into the photophase, but smaller quantities of the same volatiles were released over a broad period during the daylight hours. Laboratory-reared males peaked in pheromone release at 7–10 days and production and release continued through 35 days of age. Single males released significantly more of all components measured than did groups of males. The reduction by aggregations of males may be related to lekking behavior in this fruit fly. The pheromone probably serves to attract females to a lek site, but additional parameters are likely to enter into the choice of male made by the arriving female.This is University of Florida Agricultural Experiment Station Journal Series No. 9589.     

Identification of the major components in the secretion from the rectal pheromone glands of the queensland fruit fliesDacus tryoni andDacus neohumeralis (Diptera: Tephritidae)

The secretion from the rectal pheromone glands of maleDacus tryoni andDacus neohumeralis is largely a mixture of six aliphatic amides. In order of decreasing quantity these areN-3-methylbutylpropanamide,N-3-methylbutylacetamide,N-(3-methylbutyl-2-methylpropanamide,N-2-methylbutylpropanamide,N-2-methylbutylacetamide, andN-(2-methylbutyl)-2-methylpropanamide. The proportions of the various amides in the two species are similar.     

Male olive fruit fly attraction to synthetic sex pheromone components in laboratory and field tests

Male olive fruit fly attraction to the four synthetic components of the female sex attractant pheromone was studied under laboratory and field conditions. In laboratory tests males responded to all four components tested separately. Component I, (1,7-dioxaspiro[5.5]undecane) was more attractive than any of the remaining three components alone, but a combination of all four was more attractive than component I alone. In field tests with polyethylene vials as pheromone dispensers, the complete mixture, although not statistically significant, was constantly more attractive to males than component I alone. A tendency of enhancement of attraction of component I by combining it with component II (-pinene) or III (n-nonanal) was also observed. In field tests with rubber septa as pheromone dispensers only component I was attractive. Mixtures containing component I were also attractive but not more attractive than component I alone. Evaporation rate and ratio of components as they come out of the dispenser appear to be critical for male response.     

Chemical studies of rectal gland secretions of some species ofBactrocera dorsalis complex of fruit flies (diptera: Tephritidae)

Male-produced rectal gland secretions of a number of species now considered to be members of theBactrocera dorsalis complex of fruit flies have been examined by combined gas chromatography-mass spectrometry. The structures of a number of previously unreported compounds have been confirmed by synthesis and Chromatographic comparisons. Compounds identified in these secretions include fatty acids, esters, amides, keto alcohols, diols and spiroacetals. These chemical findings are in agreement with taxonomic revisions based on other criteria.     

Attraction ofCeratitis capitata (Diptera: Tephritidae) flies to odor of coffee fruit

On potted nonfruiting host trees in outdoor field cages, we evaluated attraction of released mature laboratory-cultured or wild-origin Mediterranean fruit flies (medflies) to odor of freshly picked fruit of host and nonhost plants. Odor of ripe intact or crushed coffee fruit (the presumed ancestral host of medflies) was significantly more attractive than odor of ripe intact or crushed fruit of five lower-ranking hosts and three nonhosts. Odor of crushed coffee fruit was significantly more attractive than odor of intact coffee fruit. Odor of ripe or near-ripe coffee fruit was significantly more attractive than odor of unripe coffee fruit. Immature females (without eggs) were significantly more attracted to odor of a proteinaceous food lure than to odor of ripe coffee fruit, whereas the reverse was true for mature females carrying a high egg load. In some trials, males proved as discriminating as females in favor of coffee fruit odor, but in several other trials males were less discriminating than females. Response patterns of mature laboratory-cultured females were similar to those of mature wild-origin females. In a field of coffee plants, attraction of natural-population females was significantly greater to odor of ripe coffee fruit than to water but was not greater than attraction to odor of proteinaceous food. Findings are discussed in relation to potential use of synthetic volatiles of coffee or other host fruit in traps for monitoring or controlling medflies.     

Chemistry of fruit flies: Glandular secretion ofBactrocera (Polistomimetes) visenda (Hardy)

The major component (>90% of volatiles) of the male rectal glandular extract of the nonpest speciesBactrocera visenda (Hardy) is 3-methyl2-butenyl acetate, with minor components being the isomeric 3-methyl-3-butenyl acetate, the homologous esters, 3-methyl-2-butenyl propanoate and 3-methyl-2-butenyl formate, along with 3-methyl-2-buten-1-ol, 3-methyl-2-butenal, and 3-methylbutyl acetate. None of these compounds has been identified previously from aBactrocera species, supporting the view thatBactrocera visenda is taxonomically distant from otherBactrocera species identified from the Australian mainland. This collection of compounds adds to the known types utilized by dipteran species and emphasizes their extensive biosynthetic capability.     

Distance of response to host tree models by female apple maggot flies,Rhagoletis pomonella (Walsh) (Diptera: Tephritidae): Interaction of visual and olfactory stimuli

Mature female apple maggot flies,Rhagoletis pomonella (Walsh), were released individually onto a single potted, fruitless hawthorne tree in the center of an open field. The tree was surrounded by four 1-m² plywood host tree models painted green or white, with or without synthetic host fruit odor (butyl hexanoate), and placed at one of several distances from the release tree. Each fly was permitted to forage freely on the release tree for up to 1 hr, or until it left the tree. Flies left the tree significantly sooner when green models with host fruit were present at 0.5, 1.5, or 2.5 m distance from the release tree than when these models were placed at a greater distance (4.5 m) from the release tree or when no models were present. Flies responded detectably to 1-m² models without odor up to a maximum distance of 1.5 m. These results suggest that female apple maggot flies did not detect green 1-m² models with odor 4.5 m away or models without odor 2.5 m or more away. Flies responded to white models with and without odor to a much lesser extent, both in terms of response distance and flight to and alightment upon models. Increasing model size to 2 m² increased the distance to 2.5 m at which flies responded to green models without odor. Decreasing model size to 0.5 m² reduced fly responsiveness to green or white models. The presence of host fruit odor alone, without the visual stimulus of a green model, did not influence residence time on the release tree.     

Trans-ceralure isomers: Differences in attraction for mediterranean fruit fly,Ceratitis capitata (Wied.) (diptera: Tephritidae)

Differences in attractiveness of four individualtrans isomers of ceralure (CRL) [ethyl 4- (and 5-) iodo-trans-2-methylcyclohexane-1-carboxylate] for male Mediterranean fruit fly,Ceratitis capitata (Wiedemann), were investigated. One of the isomers, CRL-B1 (ethylcis-5-iodo-trans-2-methylcyclohexane-1-carboxylate) was significantly superior to the three othertrans-CRL isomers, CRL, trimedlure (TML) [1,1-dimethylethyl 4- (and 5-) chloro-trans-2-methylcyclohexane-1-carboxylate], and TML-C (1,1-dimethylethyl-cis-4-chloro-trans-2-methylcyclohexane-1-carboxylate) on an equal weight basis.     

Attraction of Female Oriental Fruit Fly, Bactrocera dorsalis, to Volatile Semiochemicals from Leaves and Extracts of a Nonhost Plant, Panax (Polyscias guilfoylei) in Laboratory and Olfactometer Assays

Fresh whole leaves and solvent–water leaf extracts of the hedgerow plant panax, Polyscias guilfoylei (Bull), were tested for their attractiveness to male and female Oriental fruit flies, Bactrocera dorsalis, in laboratory flight tunnel and cage olfactometer bioassays. Fresh mature whole panax leaves were found to be attractive to mated female oriental fruit flies in the flight tunnel. Response of males and virgin females was low and in most instances not significantly different from controls. Attraction of mated female flies to the layers resulting from a methylene chloride–water partition or a hexane–water partition of freshly ground leaves using small McPhail traps was greatest in the methylene chloride fraction. When methylene chloride and water layers were tested competitively in a multiple-choice rotating olfactometer, the methylene chloride fraction was more attractive. Tests involving the methylene chloride–water interface (an emulsion of the two partitioned layers) with and without a standard attractant NuLure, showed the emulsion layer to be significantly more attractive than the other fractions or NuLure. In outdoor cage olfactometer assays of methylene chloride and water fractions, activity was greatest in the methylene chloride fraction. The results suggests that volatile semiochemicals from this nonhost plant are attractive to mated female Oriental fruit flies. The results are discussed in relation to the chemical ecology of B. dorsalis and the potential use of this nonhost plant for detection and control of female Oriental fruit flies in the field.     

Olea europaea Volatiles attractive and repellent to the olive fruit fly (Dacus oleae,Gmelin)

Comparative study of the headspace (HS) composition from olive leaves, olives of varying degrees of ripeness, and crushed olives revealed significant quantitative and qualitative differences. Three different methods were employed to test the effect of the substances identified on the behavior ofDacus oleae gravid females. Attractive/repellent features were tested by presenting the insects with olfactory choices of a water solution of the test chemicals examined, water (blank), and a highly attractive (control) solution of olive maceration water (MW). Toluene and ethylbenzene, present in leaf and half-ripe olive HIS proved attractive, while (E)-2-hexenal emitted by the crushed olives was found to be decidedly repellent. An oviposition stimulation/deterrence test was carried out on olives placed in proximity to test chemicals under examination in water solution, with olives from the same crop serving as control. In the oviposition test-pinene, mostly emitted by the leaves and half-ripe olives, emerged clearly as an activant,p-xylene, myrcenone, ethylbenzene,n-octane ando-xylene as weak activants. (E)-2-hexenal and hexanal, both emitted by the crushed olives, displayed an oviposition deterrent effect. The highly repellent property of (E)-2-hexenal was again confirmed in this test.     

A novel attractant for Mexican fruit fly,Anastrepha ludens,from fermented host fruit

Chemicals from fermented chapote fruit were identified and evaluated as attractants for hungry adult Mexican fruit flies in laboratory and greenhouse bioassays. Twenty-eight chemicals identified from an attractive gas-chromatography fraction were as attractive as a chapote volatiles extract (CV) when mixed in the same amounts found in CV. Sixteen of the chemicals were slightly attractive to flies when tested individually. A mixture containing 15 of the chemicals by design and the 16th as an impurity, in arbitrary concentrations, was at least as attractive as the original CV. In a series of experiments, the number of chemicals was reduced to three by elimination of unnecessary components. The three-component mixture retained the attractiveness of the 15-component mixture. The three chemicals were 1,8-cineole, ethyl hexanoate, and hexanol (CEH). Attractiveness of the three-chemical mixture was equal to the sum of the attractiveness of the three individual components, suggesting that each chemical binds to a different receptor type that independently elicits partial attraction behavior. Optimal ratios were 1011 of the three chemicals, respectively. Optimal test quantities ranged between 0.4–4g of 1,8-cineole and 40–400 ng each of ethyl hexanoate and hexanol applied to filter paper in the laboratory bioassays. A neat 1011 mixture of the chemicals was 1.8 times more attractive than aqueous solutions ofTorula dried yeast and borax to starved 2-day-old flies when the lures were tested in competing McPhail traps in a large greenhouse cage.Diptera: Tephritidae.     

Enantiospecific synthesis of (3S,6R)-3-hydroxy-1,7-dioxaspiro[5.5]undecane and its (4R)-4-hydroxy isomer [minor components of olive fruit fly (Dacus oleae) sex pheromone]

The synthesis of (3S,6R)-3-hydroxy-1,7-dioxaspiro[5.5]undecane (8) and its (4R)-4-hydroxy isomer (11) from (3R,4S,6R)-3,4-dihydroxy-1,7-dioxaspiro[5.5]undecane (1), obtained from D-fructose, has been accomplished by regioselective deoxygenation at C-4 and C-3, respectively, of the appropriately protected derivatives.Enantiospecific synthesis of spiroacetals. Part III. For Part II, see Izquierdo et al. (1991).     

Partial characterization and HPLC isolation of bacteria-produced attractants for the Mexican fruit fly,Anastrepha ludens

Methods were developed to collect and isolate volatile chemicals produced by aStaphylococcus bacterium in tryptic soy culture that are attractive to protein-hungry adult Mexican fruit flies. Centrifugation of bacteria culture yielded a slightly attractive pellet containing most of the bacteria cells and a highly attractive supernatant. Supernatant filtered to remove the remaining bacteria was as attractive as the unfiltered supernatant. Filtrate at pH 7 and above was much more attractive than filtrate at pH 5 and below. Most of the attractiveness was retained on strong cation exchange media under acidic conditions and eluted with base. Attractive principles could not be trapped on adsorbents such as Porapak Q or extracted with organic solvents from aqueous preparations, but they were easily collected by headspace sweeping with steam. The attractive components were efficiently concentrated by rotary evaporation of steam distillate at pH 5, but at higher pH much of the attractiveness distilled. A reverse-phase HPLC method using a negative counter-ion was developed to separate and collect attractive components of concentrated steam distillate. Attractive fractions collected using this method were concentrated and injected onto silica HPLC. Activity eluted from silica in two distinct bands. Results suggest that the most attractive components of the bacterial odor are highly polar, low-molecular-weight amines.Diptera: Tephritidae.