Attractants for synanthropic flies

Fermented molasses or sucrose solutions are known to attract several species of filth-breeding flies. To identify the volatile attractants produced in fermenting sucrose solutions with yeast, these solutions were fractionated, and the chemical constituents identified and bioassayed against filth-breeding flies includingFannia canicularis (L.),Muscina stabulans (Fallén), andMusca domestica (L.). Distillation of a fermented sucrose solution gave an active distillate and an inactive residue. Gas Chromatographic analysis of the distillate showed the presence of acetaldehyde, ethyl acetate, ethanol, 1-pro-panol, 2-methyl-l-propanol, and 3-methyl-l-butanol. Ethanol constituted by far the greatest proportion of compounds present in the distillate. An aqueous solution of ethanol exhibited the same level of attractancy as the distillate, the fermented sucrose solution, and a reconstituted distillate containing all compounds identified. Ethanol was thus identified as the sole attractant emanated from fermented carbohydrate solutions that elicited positive responses in pest flies, especially inF. canicularis.Diptera: Muscidae.     

Onion fly and little house fly host finding selectively mediated by decomposing onion and microbial volatiles

Responses of onion flies,Hylemya antiqua (Meigen), to various synthetic onion and microbial volatiles as well as volatiles from microbial cultures and decomposing onions were tested to characterize the most effective host-finding stimuli. Of nine onion and microbial volatiles tested individually, only the known attractant,n-dipropyl disulfide, caught significant numbers of flies. However, a blend of these volatiles attracted more flies than any single chemical, includingn-dipropyl disulfide. In another experiment, agar plates inoculated with microorganisms from decomposing onions did not attract onion flies. However, cut onions inoculated with microorganisms and conditioned 4 days caught more onion flies than freshly cut onions andn-dipropyl disulfide. These results suggest that a blend of chemicals, rather than a single key chemical, is the more effective host-finding stimulus, and that microbial activity enhances the attractancy of a blend of onion volatiles. Large numbers ofFannia canicularis (L.), the little house fly, responded to the microbial cultures, demonstrating the existence of a potent attractant for this muscid.Diptera: Anthomyiidae.Diptera: Muscidae.Paper No. 9470 of the Michigan State University Agricultural Experiment Station. Received for publication May 23, 1980.     

Composition of Chemical Attractants Affects Trap Catches of the Australian Sheep Blowfly, Lucilia cuprina, and Other Blowflies

Numbers of Lucilia cuprina (Australian sheep blowfly), Chrysomya spp., and Calliphora spp. blowflies caught on sticky traps baited with various synthetic attractants or a standard liver/sodium sulfide attractant in western Queensland were recorded. Numbers of each genus collected were influenced by the composition of the chemical attractants. Attractant mixtures based on 2-mercaptoethanol, indole, butanoic/pentanoic acid, and a sodium sulfide solution gave 5- to 20-fold higher L. cuprina catches than the liver standard. These blends attracted similar numbers of Chrysomya spp. (0.85-2.7x) and fewer Calliphora spp. (0.02-0.2x) compared to the liver standard. These synthetic attractants were more effective and selective for L. cuprina than the standard liver/sodium sulfide attractant, and they can be packaged in controlled-release dispensers to generate constant, prolonged release of the attractant.     

Field evaluation of chemical attractants against the flyFannia femoralis (Diptera: Muscidae)

Four chemical compounds previously shown to be attractants toHippelates eye gnats and houseflies were evaluated againstFannia femoralis (Stein). Two of the compounds, trimethylamine hydrochloride andn-butyric acid, were determined to be the principal attractants against this fly. A composition containing trimethylamine hydrochloride (yielding trimethylamine in presence of water),n-butyric acid, and an anchovy meal inert carrier proved highly attractive. To evaluate the practical use of the synthetic fly attractant (SFA) formulation, a large-scale trial over an entire poultry ranch was implemented using SFA formulation and a sugar toxicant (as a killing agent) in specially designed traps. Within 2 weeks after initiation of SFA-toxicant treatments, significant reduction inF. femoralis population from the pretreatment level occurred. This high level of reduction prevailed during the remainder of the treatment period.     

Identification of the Sex Pheromone of Holotrichia reynaudi

The male attractant pheromone of the scarab beetle Holotrichia reynaudi, an agricultural pest native to southern India, was extracted from abdominal glands of females with hexane and analyzed by gas chromatography–mass spectrometry. Field testing of the candidate chemicals, indole, phenol, and anisole, both alone and as binary mixtures, led us to conclude that anisole was the major component of the sex pheromone. Neither male nor female beetles were attracted to indole or phenol on their own. Similarly, when indole and anisole were combined, the attractiveness of the solution did not increase over that obtained with anisole alone. However, combination of phenol and anisole did alter the attractiveness of anisole, with fewer male beetles attracted to the binary mixture than to anisole on its own. The behavior of female beetles was not altered by any of the chemicals tested. Anisole is also the sex pheromone of H. consanguinea, making this the first known example of two melolonthine scarabs sharing the same pheromone.     

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.     

Production of onion fly attractants and ovipositional stimulants by bacterial isolates cultured on onion

Decomposing onions at certain microbial successional stages produce potent volatile attractants and ovipositional stimulants of the onion fly,Delia antiqua (Diptera: Anthomyiidae). A reproducible source of these compounds was obtained by culturingErwinia carotovora var.carotovora (EC) on sterile onion tissue. In laboratory choice tests, EC-inoculated onion was more attractive thanKlebsiella pneumoniae (KP) cultured on onion, EC cultured on potato (a nonhost of onion fly), or the chemical synthetic baits dipropyl disulfide and an aqueous solution of 2-phenylethanol and pentanoic acid. Onion flies were mildly attracted to potato after inoculation with EC, but females did not accept EC-inoculated potato for oviposition. This work emphasizes that sources of semiochemicals may need to be defined microbiologically as well as physically and chemically.Diptera: Anthomyiidae.Paper No. 12106 of the Michigan State University Agricultural Experiment Station.     

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.     

Semiochemical attractants ofDiabrotica undecimpunctata howardi barber,southern corn rootworm,andDiabrotica virgifera virgifera leconte,the western corn rootworm (Coleoptera: Chrysomelidae)

During the summers of 1984 and 1985, a variety of structurally related benzenoid compounds was evaluated in sweet corn plots as attractants for adult southern corn rootworms (SCR), western com rootworms (WCR), and northern corn rootworms (NCR). Field response to the volatiles was measured by beetle counts on baited cylindrical sticky traps placed inside the corn plots at a height of l m above ground level. SCR adults were attracted late in the season (last week of August through September, 1984 and 1985) to numerous aromatic compounds, including phenylacetaldehyde, benzyl acetone, phenethyl alcohol, phenyl acetate, indole, veratrole, methyl eugenol, methyl isoeugenol, eugenol, and isoeugenol. Although many compounds attracted SCR adults late in the season, only veratrole, phenylacetaldehyde, and chavicol were significantly active in early and middle August 1985. WCR adults were attracted to a different group of compounds, namely estragole,trans-anethole, and indole. Estragole (4-methoxy-1-allylbenzene) was an effective WCR attractant from corn tasseling in early August 1985, until the end of the trapping period in late September and early October 1985. Indole andtrans-anethole (4-methoxy-1-propenylbenzene) were less effective attractants than estragole and were most active at the beginning and/or end of the corn season. Traps baited with 100 mg of estragole caught an average of 20 times more WCR adults than unbaited control traps, and the females outnumbered the males in the baited traps. Estragole dosage tests were conducted in three sweet corn plots on different dates in 1985 and the minimum effective dose ranged between 5 and 30 mg/trap. Field tests with structural analogs revealed the importance of the site of unsaturation in the allylic side chain of estragole and the effect of different ring substituents on WCR response. The phenylpropanoids, eugenol and isoeugenol, significantly attracted NCR adults, even though these beetles were in low abundance in the test corn plots. Field tests indicate there is no cross-species response by WCR and NCR adults to their related phenylpropanoid attractants. However, in late August, SCR adults do respond to some WCR and NCR attractants (indole and several eugenol analogs). Electroantennographic analysis of SCR males revealed they can perceive peripherally a wide range of benzenoid compounds.     

Multicomponent attractant for female screwworm flies,Cochliomyia hominivorax,in bovine blood

An olfactometer bioassay was used to follow attractant for screwworm flies,Cochliomyia hominivorax, in steam distillates of bovine blood under different distillation and storage conditions and after HPLC separation of components in a water-methanol gradient. In addition, fly responsiveness was examined in relation to sex and ovarian stage. Gravid and vitellogenic nullipars were attracted to the blood, although the former predominated four to one. Males did not respond at a dose that attracted 76% of gravid females. Maximum attractiveness occurred when distillate was stored in sealed glass ampoules. An argon atmosphere made storage at ambient temperatures feasible, but offered no advantage during storage at ca. –60°C or during distillation. The HPLC separation produced four fractions that duplicated the attractiveness of the distillate when recombined but showed little activity when presented as two-fraction, and most three-fraction, mixtures. Availability of the HPLC fractions for combination with other samples will facilitate location via bioassay of attractant components in samples obtained from subsequent or alternate isolations that preserve only one or two elements of the multicomponent mixture.Mention of a proprietary product does not constitute an endorsement or recommendation for its use by the USDA.     

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.     

Yeast and corn hydrolysates and other nutritious materials as attractants for onion and seed flies

The attractancy of enzymatic yeast hydrolysate, a corn hydrolysate, brewers' yeast, honey, ammonia,n-dipropyl disulfide, and several combinations of these treatments was tested in an onion field containing onion flies,Hylemya antiqua (Meigen) and seedcorn flies,H. platura (Meigen). Enzymatic yeast hydrolysate (concentrated powder) proved to be highly attractive to both fly species; females were more responsive than males. Brewers' yeast and corn hydrolysate were intermediately attractive, while all other treatments were only slightly or not at all attractive. Although no steps were taken to prolong release of volatiles, some of the nutritious materials remained highly attractive even after 11 days. The yeast products may, at certain times, be even more attractive than specific host volatiles. However, their activity was not constant over time and may be influenced by the stage of reproductive development of female flies.Diptera: AnthomyiidaePaper No. 9511 of the Michigan State University Agricultural Experiment Station.     

Mutual Reproductive Benefits Between a Wild Orchid, Bulbophyllum patens, and Bactrocera Fruit Flies via a Floral Synomone

The solitary flower of Bulbophyllum patens selectively attracts male fruit flies of several Bactrocera species with a specific fragrance in the rain forest of Malaysia. It temporarily traps flies between its hinged see-saw lip and column for pollination. The attractant component is zingerone [4-(4-hydroxy-3-methoxyphenyl)-2-butanone], a pungent essence of ginger. Zingerone has a structure resembling two major fruit fly attractants (methyl eugenol and raspberry ketone) and shows potency to attract a wide range of fruit fly species (B. carambolae, B. caudata, B. cucurbitae, B. tau, and B. umbrosa). A fruit fly visitor is rewarded by feeding on zingerone, and in return it removes the pollinarium and then transfers it to another flower. Males of the melon fly acquire the floral essence and selectively store it in the pheromone gland to attract conspecific females. Males of B. papayae, however, convert zingerone to zingerol in the crop. The latter compound is stored in the rectal gland and subsequently released to attract females. This provides a rare example of a mutualistic interaction between insects and plants via a floral synomone, in which both organisms obtain advantages directly benefiting their reproductive systems.     

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.     

Isolation and identification of a sex attractant of a mushroom-infesting sciarid fly

A sciarid fly,Lycoriella mali (Fitch), is one of the most destructive pests to the commercial mushroom,Agaricus bisporus (Lange) Singer. Sanitation procedures and pesticide applications were ineffectual in controlling this pest. A supplemental pest control method employing sex pheromones was suggested since previous work indicated the presence of a sex attractant in the female. Diagnostic reactions performed on female extracts indicated saturated hydrocarbons as active components. The biologically most active fractions eluted from the gas chromatograph between standard hydrocarbons C₁₅ and C₂₂. Hydrocarbons C₁₅, C₁₆, C₁₇, and C₁₈ were isolated and identified via TLC, GC, and GC-MS. Male response to standard hydrocarbons C₁₅ to C₂₆ indicated that C₁₇ is a major attractant. Male response to varying amounts of C₁₇ indicated a preference for levels 10^–6g and 10^–9g.     

Floral Phenylpropanoid Cocktail and Architecture of Bulbophyllum vinaceum Orchid in Attracting Fruit Flies for Pollination

It is widely believed that most orchid flowers attract insects by using deception or chemical rewards in the form of nectar. Flowers of Bulbophyllum vinaceum produce a large array of phenylpropanoids that lure tephritid fruit fly males and also act as floral reward, which the flies subsequently convert to pheromone components. The major floral volatile components identified are methyl eugenol (ME), trans-coniferyl alcohol (CF), 2-allyl-4,5-dimethoxphenol (DMP), and trans-3,4-dimethoxycinnamyl acetate, whereas the minor components are eugenol, euasarone, trans-3,4-dimethoxy cinnamyl alcohol, and cis-coniferyl alcohol. Among the various floral parts, the lip (which is held in a closed position up against the sexual organs) has the highest concentration of the major compounds. An attracted male fly normally lands on one of the petals before climbing up onto and forcing the “spring loaded” floral lip into the open position, hence exposing the floral sexual organs. The architecture and location of chemical attractants of the lip compel the fly to align itself along the lip’s longitudinal axis in a precise manner. As the fly laps up the compounds and moves towards the base of the lip, it passes the point of imbalance causing the lip to spring back to its normal closed position. The fly is catapulted headfirst into the column cavity, and its dorsum strikes the protruding sticky base of the hamulus and adheres to it. The momentum of the fly and the structural morphology of the long stiff hamulus act to pry out the pollinia from its anther cover. Hence, the pollinarium (pollinia + hamulus) is detached from the flower and adhered to the fly’s dorsum. In this unique mutualistic association, both species receive direct reproductive benefits—the flower’s pollinarium is transported for cross pollination, and the fly is offered a bouquet of phenylpropanoids (synomone) that it consumes, converts, and/or sequesters as sex pheromonal components, thus enhancing sexual attraction and mating success.     

Effects of Enantiomeric Blend of Verbenone on Response ofIps paraconfusus to Naturally Produced Aggregation Pheromone in the Laboratory

The aggregation pheromone produced by maleIps paraconfusus (Coleoptera: Scolytidae) tunneling in Monterey pine,Pinus radiata, logs was trapped on Porapak Q. A concentration of an extract of trapped volatiles that attracted beetles was determined in the laboratory through a concentration–response analysis of walking behavior of males and females. The interruptant effects of four concentrations of verbenone on response to a constant concentration of this naturally produced aggregation pheromone were tested with males and females. Independent of its enantiomeric composition [99.5% (S)-(–), 93.1 % (S)-(–), and 98.3% (R)-(+)], verbenone significantly reduced the percentage of females (but not males) reaching the attractant source. However, when the time required for beetles of both sexes taken together to reach the attractant source was considered, verbenone of higher enantiomeric purity had a greater effect on beetle behavior. Solutions of 99.5% (S)-(–)- and 98.3% (R)-(+)-verbenone increased the time required for beetles to reach the attractive source when compared to 93.1% (S)-(–)-verbenone. When pooled across enantiomeric blends, increasing concentrations of verbenone resulted in slower responses in beetles that reached the attractant source within 2 min. Males and females did not respond to verbenone alone.     

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.     

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.     

Effective attraction radius

The catches of bark beetles (Coleoptera: Scolytidae) were compared between attractive traps releasing semiochemicals and passive traps (cylindrical sticky screens hung, at 10 heights of 0.7–11.5 m, on poles). A central attractive-trap pole was surrounded by three passive-trap poles spaced 50 or 100 m away at the apices of an equilateral triangle. The catches ofTomicus piniperda and other scolytid species on the attractive-trap pole baited with host monoterpenes, or the catches ofIps typographus attracted to synthetic pheromone, were compared to passive trap catches in a Scots pine forest or in a Norway spruce clear-cut, respectively. Information about flight height distributions of the above scolytid species, andHylurgops palliatus, Cryphalus abietis, Pityogenes chalcographus, P. quadridens, P. bidentatus, andTrypodendron domesticum were obtained on the passive and attractive trap poles. A new method is presented for determining the densities of flying insects based on the passive trap's dimensions and catch, duration of test, and speed of insect. Also, a novel concept, the effective attraction radius (EAR), is presented for comparing attractants of species, which is independent of insect density, locality, or duration of test. The EAR is obtained by the ratio of attractive and passive trap catches and the dimensions of the passive trap, and thus should correlate positively with the strength of the attractant and the distance of attraction. EARs are determined from catch data ofT. piniperda andI. typographus as well as from the data of previous investigations on the same or other bark beetles.