Ring-Fluorinated Analog of Methyl Eugenol: Attractiveness to and Metabolism in the Oriental Fruit Fly, <Emphasis Type="Italic">Bactrocera Dorsalis</Emphasis> (Hendel)

Oriental fruit fly, Bactrocera dorsalis (Hendel), males are highly attracted to the natural phenylpropanoid methyl eugenol (ME). They compulsively feed on ME and metabolize it to ring and side-chain hydroxylated compounds that have both pheromonal and allomonal functions. Side-chain metabolic activation of ME leading to (E)-coniferyl alcohol has long been recognized as a primary reason for hepatocarcinogenicity of this compound in rodents. Earlier, we demonstrated that introduction of a fluorine atom at the terminal carbon of the ME side chain significantly depressed metabolism and specifically reduced formation of coniferyl alcohol but had little effect on field attractiveness to B. dorsalis. In the current paper, we demonstrate that fluorination of ME at the 4 position of the aromatic ring blocks metabolic ring-hydroxylation but overall enhances side-chain metabolism by increasing production of fluorinated (E)-coniferyl alcohol. In laboratory experiments, oriental fruit fly males were attracted to and readily consumed 1,2-dimethoxy-4-fluoro-5-(2-propenyl)benzene (I) at rates similar to ME but metabolized it faster. Flies that consumed the fluorine analog were as healthy post feeding as ones fed on methyl eugenol. In field trials, the fluorine analog I was ∼50% less attractive to male B. dorsalis than ME.

Di- and Tri-fluorinated Analogs of Methyl Eugenol: Attraction to and Metabolism in the Oriental Fruit Fly, Bactrocera Dorsalis (Hendel)

Oriental fruit fly, Bactrocera dorsalis (Hendel), males are attracted to the natural phenylpropanoid methyl eugenol (ME). They feed compulsively on ME and metabolize it to ring and side-chain hydroxylated compounds that have both pheromonal and allomonal properties. Previously, we demonstrated that mono-fluorination at the terminal carbon of the ME side-chain significantly reduced metabolic side-chain hydroxylation, while mono-fluorination of ME at position 4 of the aromatic ring blocked ring-hydroxylation but surprisingly enhanced side-chain hydroxylation. Here, we demonstrated that the introduction of fluorine atoms on both the ring and side-chain of ME blocks both positions that undergo enzymatic hydroxylation and, in particular, completely inhibits oxidative biotransformation of the allyl group. In laboratory experiments, B. dorsalis males initially were more attracted to both 1-fluoro-4,5-dimethoxy-2-(3,3-difluoro-2-propenyl)benzene (I) and 1-fluoro-4,5-dimethoxy-2-(3-fluoro-2-propenyl)benzene (II) than to ME. However, both I and II were taken up by flies at rates significantly less than that of ME. Flies fed with difluoroanalog II partially metabolized it to 5-fluoro-4-(3-fluoroprop-2-en-1-yl)-2-methoxyphenol (III), and flies fed with trifluoroanalog I produced 4-(3,3-difluoroprop-2-en-1-yl)-5-fluoro-2-methoxyphenol (V), but the rates of metabolism relative to rates of intakes were much lower compared to those of ME. Flies that consumed either the tri- or difluorinated analog showed higher post-feeding mortality than those that fed on methyl eugenol. In field trials, trifluoroanalog I was ～90% less attractive to male B. dorsalis than ME, while difluoroanalog II was ～50% less attractive. These results suggest that increasing fluorination can contribute to fly mortality, but the trade off with attractancy makes it unlikely that either a di or trifluorinated ME would be an improvement over ME for detection and/or eradication of this species.     

Floral synomone of a wild orchid,Bulbophyllum cheiri,lures Bactrocera fruit flies for pollination

The major fruit fly attractant component in the floral fragrance of Bulbophyllum cheiri (fruit fly orchid) is methyl eugenol (ME). In the lowland rain forest of Malaysia, the solitary and nonresupinate flowers of the fruit fly orchid attract only males of the ME-sensitive fruit fly species (Bactrocera carambolae, B. papayae, and B. umbrosa. During the morning, the fruit fly orchid flower is visited by many fruit flies, which can sometimes cover the whole flower. The number of visitors dwindles in the afternoon. Headspace analysis of the flower shows a high ME peak in the morning, a small one between 12:00 and 14:00 hr, and no detectable ME peak after 14:00 hr. The process of pollination in the wild is initiated by attraction of fruit flies to floral ME. The flower, with the aid of its specialized hinged see-saw lip (labellum), temporarily traps (<1 min) a fruit fly pollinator between its lip and column. Just prior to this, the fly is rewarded by the opportunity to feed on the floral attractant found on surfaces of petals, sepals, and lip. The pollinaria borne by two wild B. papayae males (caught on and near the fruit fly orchid flower) are identical in morphology and structure with those obtained from the flower. Many of the B. papayae males (17 of 22 analyzed) attracted to the fruit fly orchid already possessed both ME metabolites, trans-coniferyl alcohol and 2-allyl-4,5-dimethoxyphenol, in their rectal glands, indicating that they had previously consumed ME. In this orchid–fruit fly association, both organisms gain direct reproductive benefits: the orchid flower gets pollinated without having to offer nectar, while the fruit fly boosts its pheromone and defense system, as well as its sexual competitiveness by feeding on the ME produced by the flower.     

Accumulation of Phenylpropanoid and Sesquiterpenoid Volatiles in Male Rectal Pheromonal Glands of the Guava Fruit Fly, <Emphasis Type="Italic">Bactrocera correcta</Emphasis>

The guava fruit fly, Bactrocera correcta, is widely distributed in Thailand and other surrounding Southeast Asian countries, and, like the closely related sympatric species, the oriental fruit fly, B. dorsalis, infests various fruits, including guava, peach, and mango. Males of both B. correcta and B. dorsalis are strongly attracted to, and compulsively feed on, methyl eugenol (ME). Bactrocera dorsalis males fed on ME sequester its metabolite phenylpropanoids, (E)-coniferyl alcohol and 2-allyl-4,5-dimethoxyphenol, in the rectal pheromone gland. In contrast, B. correcta males fed on ME sequester two different metabolites, (Z)-coniferyl alcohol (ZCF) and (Z)-3,4-dimethoxycinnamyl alcohol (DMC), in the rectal gland. Examination of the temporal changes of ME metabolites in B. correcta male rectal glands revealed that the total of ZCF and DMC was as high as 100 μg/male at 24 hr after ME feeding. ZCF and DMC were detected in a large proportion of wild B. correcta males captured at various sites in Thailand. Since B. correcta and B. dorsalis are sympatric species in Thailand, these two different subsets of rectal phenylpropanoids could play a role to avoid interbreeding between the species. Further survey of wild flies in Thailand revealed that a large proportion of males of B. correcta store large quantities (over 250 μg/gland) of sesquiterpene hydrocarbons, including β-caryophyllene, α-humulene, and alloaromadendrene in the rectal gland in addition to, or instead of, ZCF and DMC. Laboratory-reared males also sequestered β-caryophyllene and α-humulene, along with ZCF and DMC, when the sesquiterpenes were artificially supplied together with ME. A field test demonstrated that a mixture (1:1) of β-caryophyllene and α-humulene attracted male B. correcta, albeit in smaller numbers than in traps baited with ME. The sequestration of sesquiterpenes, in addition to the different ME metabolites in the pheromone gland in B. correcta males, contrasts with the situation in B. dorsalis males, suggesting a potential role in intra and/or inter-specific interactions between these sympatric species.     

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.     

Can Ménage-À-Trois be Used for Controlling Insects?

We propose a new cross-species disruption approach that might be capable of interrupting mating of one species that uses another insect species as the mercenary agent. We argue that insects treated with a sufficiently powerful attractant for a second species might interfere with mating of one or both species, for example, by leading males astray in pursuit of the false trails created by suitably dosing individuals of the first species. Our reciprocal test systems used (1) methyl eugenol, an attractant for male oriental fruit flies (Bactrocera dorsalis), applied to melon flies (B. cucurbitae) and (2) cuelure, a lure for male melon flies, applied to B. dorsalis. There was no mortality 1 week after either attractant was applied to individual flies at doses up to 100 ng, which was effective in attracting insects in a field cage and in the field. In wind tunnel choice tests, 100 ng of either lure topically applied to tethered flies attracted fruit fly males of the second species, which exhibited prolonged bouts of physically disruptive behaviors including chasing and bumping. In small cages, treatment of males did not reduce mating of either species, with one group of three (ménage) per cage. However, in large field cages with multiple pairs of both species present, there was a significant reduction in the mating of melon flies resulting from methyl eugenol applied to males compared to untreated controls. The treatment of oriental fruit flies with cuelure also reduced their mating to a lesser extent. These results do not yet provide the practical proof of this new concept for pest management, but other model systems may be more appropriate. This work is novel in presenting attractants on a moving target, in this case, another insect species. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Female-Biased Attraction of Oriental Fruit Fly, Bactrocera dorsalis (Hendel), to a Blend of Host Fruit Volatiles From Terminalia catappa L.

Coupled gas chromatography-electroantennogram detection (GC-EAD) analysis of volatiles from tropical almond fruit, Terminalia catappa L., revealed 22 compounds that were detected by antennae of oriental fruit fly females, Bactrocera dorsalis (Hendel). Both solid-phase microextraction (SPME) and Porapak Q were used for sampling odors in fruit headspace, with SPME collections producing larger EAD responses from a greater number of compounds. Geranyl acetate and methyl eugenol elicited the largest EAD responses. A synthetic blend containing SPME collected, EAD stimulatory compounds showed female-biased attraction in laboratory wind tunnel bioassays, but heavily male-biased trap captures in a larger olfactometer arena. A nine-component subset of compounds eliciting relatively small EAD responses (EAD minor) and consisting of equal parts ethanol, ethyl acetate, ethyl hexanoate, hexyl acetate, linalyl acetate, ethyl nonanate, nonyl acetate, ethyl cinnamate, and (E)-β-farnesene, attracted mainly females. This EAD minor blend was as attractive to females and much less attractive to males when compared to torula yeast in field cage experiments using glass McPhail traps. Similar results were obtained with outdoor rotating olfactometer tests in which the EAD minor blend was almost completely inactive for males.     

Evidence of Natural Hybridization Between Two Sympatric Sibling Species of <Emphasis Type="Italic">Bactrocera dorsalis</Emphasis> Complex Based on Pheromone Analysis

Bactrocera carambolae and B. papayae are major fruit fly pests and sympatric sibling species of the B. dorsalis complex. They possess distinct differences in male pheromonal components. In the 1990s, wild Bactrocera fruit flies with morphological traits intermediate between those of B. carambolae and B. papayae were often captured in traps baited with methyl eugenol (ME). Chemical analyses of rectal glands of ME-fed males revealed that the laboratory F₁, F₂, and backcross hybrids possessed ME-derived sex pheromonal components ranging from that typical of B. papayae to that of B. carambolae without any specific trend, which included a combination of pheromonal components from both parental species within an individual hybrid. ME-fed hybrids without any ME-derived pheromonal components were also detected. Further chemical analysis of rectal glands from wild Bactrocera males, after ME feeding in the laboratory, showed a combination of pheromonal components similar to that found in the ME-fed, laboratory-bred hybrids. These findings present circumstantial evidence for the occurrence of a natural hybrid of the two Bactrocera species.     

Raspberry Ketone Trifluoroacetate,a New Attractant for the Queensland Fruit Fly, <Emphasis Type="Italic">Bactrocera Tryoni</Emphasis> (Froggatt)

Queensland fruit fly, Bactrocera tryoni (Q-fly), is a major pest of horticultural crops in eastern Australia. Lures that attract male Q-fly are important for detection of incursions and outbreaks, monitoring of populations, and control by mass trapping and male annihilation. Cuelure, an analog of naturally occurring raspberry ketone, is the standard Q-fly lure, but it has limited efficacy compared with lures that are available for some other fruit flies such as methyl eugenol for B. dorsalis. Melolure is a more recently developed raspberry ketone analog that has shown better attraction than cuelure in some field studies but not in others. A novel fluorinated analog of raspberry ketone, raspberry ketone trifluoroacetate (RKTA), has been developed as a potential improvement on cuelure and melolure. RKTA placed on laboratory cages containing 2-week-old Q-flies elicited strong behavioral responses from males. Quantification of Q-fly responses in these cages, using digital images to estimate numbers of flies aggregated near different lures, showed RKTA attracted and arrested significantly more flies than did cuelure or melolure. RKTA shows good potential as a new lure for improved surveillance and control of Q-fly.     

Relationship of sexual maturation rate to response of oriental fruit fly strains (Diptera: Tephritidae) to methyl eugenol

Laboratory-reared and wild, fruit-reared adults of the Oriental fruit fly,Dacus dorsalis Hendel, were tested for response to methyl eugenol at various ages. Virgin laboratory (2, 4, 6, 8, and 10 days old) and wild (7, 11, 15, 19, and 23 days old) flies were released into an outdoor field cage and trapped over a two-day period. Response of males increased with age as ca. 32% and 22% of laboratory and wild males responded at 2 and 7 days of age, respectively, while ca. 93% of both strains responded at 10 and 23 days of age, respectively. These correspond approximately to the ages at which they reach sexual maturity. Female response did not increase with age and fluctuated between 15% and 29% for the laboratory strain and 10% and 45% for the wild strain. The age-related response profiles, when integrated with sexual maturation curves, indicate that one of the major reasons the male-annihilation technique is effective is because methyl eugenol is able to attract 40–50% of male flies prior to the onset of sexual maturation.     

中间体O-3-氯-2-丙烯基羟胺的制备

以乙酸乙酯和盐酸羟胺为原料，经过乙酰胺化、醚化和水解三步反应合成了环己烯酮类除草剂的中间体0-3-氯-2-丙烯基羟胺，总收率超过90％，纯度(GC)大于99％。     

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.     

O-3-氯-2-丙烯基羟胺热危险性及其淬灭研究

为研究O-3-氯-2-丙烯基羟胺(简称氯代胺)的热危险性及其淬灭,采用差示扫描量热仪(DSC)和绝热量热仪(Phi-TEC)对其进行了测试.DSC测试结果表明,与气氛、升温速率相比,样品质量对氯代胺热危险性的影响较大,当氯代胺质量超过1 mg时,热分解过程中会出现爆炸性放热.在样品质量为0.56 mg、升温速率为4 ℃...     

Pharmacophagy of Methyl Eugenol by Males Enhances Sexual Selection of <Emphasis Type="Italic">Bactrocera carambolae</Emphasis>

After pharmacophagy of methyl eugenol (ME), males of Bactrocera carambolae (Diptera: Tephritidae) produced (E)-coniferyl alcohol (CF) along with its endogenously synthesized pheromonal compounds. CF was shown to be released into the air by the ME-fed males only during the courtship period at dusk and attracted significantly more males and females than the ME-deprived males in wind tunnel assays. However, earlier onset of sexual attraction and a higher mating success were observed only in the wind tunnel and field cage assays on the third day posttreatment of ME. Field cage observations on the male-to-male interaction indicated that the ME-deprived males did not exhibit aggregation behavior, but that ME feeding promoted aggregation behavior in B. carambolae. Field cage observations revealed that the ME-deprived males were not only attracted to the ME-fed males, but also appeared to feed on their anal secretions. The secretions were subsequently confirmed to contain CF along with endogenously produced pheromonal compounds. Results obtained for B. carambolae were compared to those previously obtained from its sibling species, Bactrocera dorsalis, and are discussed in light of species advancement in fruit fly–plant relationships.     

Accumulation ofDendrobium superbum (orchidaceae) fragrance in the rectal glands by males of the melon fly,Dacus cucurbitae

4-(4-Hydroxyphenyl)-2-butanone was characterized from flowers of the orchidDendrobium superbum as a specific attractant factor for the male melon fly,Dacus cucurbitae. The male flies compulsively licked the flower surface and sequestered the compound in significant quantities in their rectal glands. The compound was detected within 6 hr after ingestion and was retained for more than six days in the rectal gland sacs.     

Isolation and Identification of Host Cues from Mango, <Emphasis Type="Italic">Mangifera indica</Emphasis>, That Attract Gravid Female Oriental Fruit fly, <Emphasis Type="Italic">Bactrocera dorsalis</Emphasis>

The oriental fruit fly, Bactrocera dorsalis, is an economically damaging, polyphagous pest of fruit crops in South-East Asia and Hawaii, and a quarantine pest in other parts of the world. The objective of our study was to identify new attractants for B. dorsalis from overripe mango fruits. Headspace samples of volatiles were collected from two cultivars of mango, ‘Alphonso’ and ‘Chausa’, and a strong positive behavioral response was observed when female B. dorsalis were exposed to these volatiles in olfactometer bioassays. Coupled GC-EAG with female B. dorsalis revealed 7 compounds from ‘Alphonso’ headspace and 15 compounds from ‘Chausa’ headspace that elicited an EAG response. The EAG-active compounds, from ‘Alphonso’, were identified, using GC-MS, as heptane, myrcene, (Z)-ocimene, (E)-ocimene, allo-ocimene, (Z)-myroxide, and γ-octalactone, with the two ocimene isomers being the dominant compounds. The EAG-active compounds from ‘Chausa’ were 3-hydroxy-2-butanone, 3-methyl-1-butanol, ethyl butanoate, ethyl methacrylate, ethyl crotonate, ethyl tiglate, 1-octen-3-ol, ethyl hexanoate, 3-carene, p-cymene, ethyl sorbate, α-terpinolene, phenyl ethyl alcohol, ethyl octanoate, and benzothiazole. Individual compounds were significantly attractive when a standard dose (1 μg on filter paper) was tested in the olfactometer. Furthermore, synthetic blends with the same concentration and ratio of compounds as in the natural headspace samples were highly attractive (P < 0.001), and in a choice test, fruit flies did not show any preference for the natural samples over the synthetic blends. Results are discussed in relation to developing a lure for female B. dorsalis to bait traps with.     

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.     

2-氟-3-氯-5-三氟甲基吡啶的合成方法评述

2-氟-3-氯-5-三氟甲基吡啶是一种重要的含氟吡啶类中间体,在农药、医药合成中有广泛的应用。综述了2-氟-3-氯-5-三氟甲基吡啶的常用合成路线,并对各条合成路线作了比较和评价。     

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.     

Deterrence of repeated oviposition by fruit-marking pheromone inCeratitis capitata (Diptera: Tephritidae)

During ovipositor dragging on the fruit surface following egg laying in hawthorne fruit,Ceratitis capitata (Wiedemann) females deposit an unidentified pheromone that deters repeated oviposition attempts in that fruit. The pheromone proved water soluble and, when collected and sprayed in aqueous solution onto uninfested fruits in laboratory cages, effectively deterred boring attempts byC. capitata females of wild origin for at least 6 days (termination of test). A laboratory population ofC. capitata cultured on artificial media for more than 200 generations deposited pheromone that proved equally as deterrent to wild fly oviposition as pheromone from wild flies. However, lab fly oviposition was not effectively deterred by the presence of pheromone. The ecological significance of the pheromone is discussed.