Volatiles as Attractants of Mahogany Shoot Borer, Hypsipyla grandella Zeller (Lepidoptera: Pyralidae).

The mahogany shoot borer, Hypsipyla grandella Zeller (Lepidoptera: Pyralidae), is one of the most economically important pests in all American tropical forests because it prevents the establishment of monoculture plantations of the family Meliaceae, such as Spanish cedar, Cedrela odorata L. Various studies have focussed on the bioecological aspects and the chemical and silvicultural control of this pest. However, relatively little is known about the biological interactions between this insect and its host plant. In this study, the shoot borer's behavior and attraction response to cedar host plants was evaluated in field cages. We also identified the volatiles emitted by healthy C. odorata plants that were attractive to H. grandella adults. The attraction to headspace volatiles from cedar plants and a synthetic blend were evaluated in a Y-glass tube olfactometer. We observed that virgin and mated females exhibited low activity at night, frequent movement of the antennae, sporadic flight activity, and short (< 10 s) and long (> 30 s) wing-fanning. Virgin females assumed a calling position, whereas mated females exhibited three periods of oviposition. The results showed that all evaluated categories - virgin females, virgin males, and mated females - were attracted to cedar plants. We identified the following volatile compounds: α-pinene, (E)-ß-ocimene, 2-ethyl-1-hexanol, limonene, nonanal, (E)-4,8-dimethyl-1,3,7-nonatriene, α-copaene, ß-caryophyllene, and germacrene D. A synthetic blend significantly attracted virgin male and mated female shoot borers. Our results suggested that C. odorata volatiles compounds are responsible for the attraction of H. grandella.

How to repel a killer; chemical identification and effective repellent activity of commercial essential oils against kissing bugs.

Triatomines are haematophagous insects, some species are vectors of Trypanosoma cruzi, the aetiological agent of Chagas disease. The main strategy for interrupting T. cruzi transmission is to avoid contact of the vector populations with humans. Volatiles from commercial essential oils are excellent candidates to serve as repellents of kissing bugs. We used an exposure device to assess the repellence effect of eight commercial essential oils on Triatoma pallidipennis. The most effective oils were blended and evaluated against T. infestans, T. pallidipennis and Rhodnius prolixus. The blend was also evaluated on parasitised T. pallidipennis. Data were compared with the commercial repellent NN-diethyl-3-methylbenzamide. We recorded the time the insects spent in the proximity of the host and determined if any of the evaluated oils served as kissing bug repellent. We found commercial essential oils and a blend that significantly reduced the time spent in the proximity of the host. The blend was effective for use by human males and females, repelling infected and non-infected insects. The study of essential oils as repellents of blood-sucking disease-vector insects could shed light on the development of new control strategies.

Attraction of the two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae), to healthy and damaged strawberry plants mediated by volatile cues.

Tetranychus urticae Koch (Acari: Tetranychidae), the two-spotted spider mite, is a pest that limits strawberry production in Mexico. Little is known about the interactions that occur between T. urticae and healthy strawberry plants or strawberry plants infested by conspecific spider mites. Therefore, in this study we evaluated the attraction of T. urticae to healthy strawberry plants mediated by volatile organic compounds (VOCs), and to plants damaged by conspecifics mediated by herbivore-induce plant volatiles (HIPVs). First, we conducted dual-choice tests using a Y-tube olfactometer with plants and extracts obtained through dynamic aeration. The volatile composition of the extracts was identified using gas chromatography-mass spectrometry (GC-MS). Once the compounds were identified, we also conducted dual-choice tests with selected synthetic compounds. Tetranychus urticae exhibited greater attraction to both healthy and damaged plants compared to the control (clean air). However, when healthy and damaged plants were offered simultaneously, there was no significant preference observed. Bioassays with extracts obtained by dynamic aeration yielded similar results. The identified compounds were terpenes and aromatic hydrocarbons. We found qualitative and quantitative changes between the VOCs emitted by the healthy plant and the HIPVs from mite-damaged plants. The individual compounds α-pinene (10 ng), pseudocumene (10 ng), and limonene (1 ng) and 10 ng of the blend made of α-pinene + pseudocumene + mesitylene + limonene (5:34:57:4) attracted more T. urticae than the control. However, the binary blend of pseudocumene + limonene (91:9) was more attractive than the other binary or three-compound blends evaluated. These results may contribute to developing strategies for the management of this pest.

Volatile Organic Compounds Produced by Cacao Endophytic Bacteria and Their Inhibitory Activity on Moniliophthora roreri.

Several studies have reported that bacteria produce anti-fungal volatiles. We identified the organic volatile compounds produced by six cacao endophytic bacteria (CEB) strains (Bacillus amyloliquefaciens CFFSUR-B35, Bacillus megaterium CFFSUR-B32, Bacillus muralis CFFSUR-B39, Bacillus pumilus CFFSUR-B34, Bacillus subtilis CFFSUR-B31, and Novosphingobium lindaniclasticum CFFSUR-B36). We evaluated their inhibitory effect on mycelium growth and spore germination of the phytopathogenic fungus Moniliophtora roreri. The volatiles produced by these six CEB, were collected and identified by SPME and GC-MS. Moreover, the inhibitory effect of five synthetic volatile organic compounds, individually and in mixtures (dimethyl disulfide, 2-5 dimethyl pyrazine, α-pinene, 2-heptanone and 2-ethyl hexanol) on M. roreri mycelium growth and spore germination was evaluated. All strains examined produced volatiles in different amounts; 13 to 10 compounds were identified, including sulfide, alcohol benzene derivate, pyrazine, ketone, nitrogen and terpene compounds. The B. subtilis CFFSUR-B31 strain produced the largest number of volatiles, while B. pumilus CFFSUR-B34 produced the fewest and the lowest amounts. The volatile organic compounds produced by B. pumilus CFFSUR-B34, B. muralis CFFSUR-B39 and N. lindaniclasticum CFFSUR-B36 inhibited M. roreri mycelium growth by more than 35%, sporulation by more than 81% and spore germination by more than 74%. However, when synthetic compounds were evaluated individually and in mixtures, 2-ethyl hexanol at 100,000 ppm (20 mg/filter paper disc) inhibited M. roreri mycelium growth by 100%, followed by organic volatile compound mixtures C (dimethyl disulfide, 2,5-dimethyl pyrazine, α-pinene, 2-ethyl-hexanol, 2-Heptanone) and D (only the top four) at 100,000 ppm (4 and 5 mg/filter paper disc) which inhibited spore germination by 97 and 89%, respectively.

Variation in the cuticular hydrocarbons of the Mexican fruit fly Anastrepha ludens males between strains and age classes.

In this study cuticular hydrocarbons (CHCs) were characterized from wings of individual unmated males of different Anastrepha ludens (Loew) mass-reared strains of different ages (3 and 19-day-old): (a) a standard mass-reared colony (control), (b) a genetic sexing strain, (c) a selected strain, (d) a hybrid strain, and (e) wild males. We found that the hydrocarbon profiles in all males included two n-alkanes, five monomethyl alkanes, and two alkenes. CHCs ranged from C26 to C31 . The most prominent peaks were 2-methyloctacosane (2-Me-C28), n-nonacosene (C29:1), 2-methyltriacontane (2-Me-C30), and n-hentriacontene (C31:1). Significant variations in the CHC amounts of the mass-reared strains were observed from Day 9 and thereafter. Comparison of CHCs using multivariate and canonical analyses across ages and among mass-reared strains and wild males revealed qualitative and quantitative differences. The relative amounts of C29:1 and 2-Me-C30 were significantly higher across age groups in the mass-reared strains than those in the wild males. In contrast, amounts of n-nonacosane (C29) significantly increased in wild males as they aged. Through statistical analyses, we inferred that CHC amounts vary with age. Wild males differed significantly from the mass-reared strains in the amount of C29, and the genetic sexing strain Tap-7 had significantly higher values for 2-methylhexacosane (2-Me-C26). In contrast the selected and control strain differed from the other strains in amounts of C29:1 and 2-Me-C30. We suggest that differential profiles in hydrocarbon composition among the strains may be mainly due to environmental pressures.

The Stingless Bee Melipona solani Deposits a Signature Mixture and Methyl Oleate to Mark Valuable Food Sources.

Stingless bees foraging for food improve recruitment by depositing chemical cues on valuable food sites or pheromone marks on vegetation. Using gas chromatography/mass spectrometry and bioassays, we showed that Melipona solani foragers leave a mixture composed mostly of long chain hydrocarbons from their abdominal cuticle plus methyl oleate from the labial gland as a scent mark on rich food sites. The composition of hydrocarbons was highly variable among individuals and varied in proportions, depending on the body part. A wide ratio of compounds present in different body parts of the bees elicited electroantennogram responses from foragers and these responses were dose dependent. Generally, in bioassays, these bees prefer to visit previously visited feeders and feeders marked with extracts from any body part of conspecifics. The mean number of visits to a feeder was enhanced when synthetic methyl oleate was added. We propose that this could be a case of multi-source odor marking, in which hydrocarbons, found in large abundance, act as a signature mixture with attraction enhanced through deposition of methyl oleate, which may indicate a rich food source.

Influence of Methoprene on Pheromone Emission and Sexual Maturation of Anastrepha obliqua (Diptera: Tephritidae) males.

It has been demonstrated that the application of juvenile hormone analog, methoprene, reduces the time required for sexual maturation and enhances mating success in several species of tephritid fruit flies. This study examined the effect of different concentrations of methoprene incorporated into the diet of adult flies and distinct sugar:protein (S:P) ratios on sexual maturity and pheromone emission of Anastrepha obliqua males. Diets with 0.2 and 0.5% of methoprene accelerated sexual maturation of males compared with untreated males. In subsequent assays, the enhancement of male pheromone emission and sexual maturation by the incorporation of 0.02% methoprene into a 24:1 (S: P) diet was confirmed. Among the volatiles released by males, (Z)-3-nonenol and (Z,Z)-3,6-nonadienol were emitted at higher quantities by flies treated with methoprene than untreated ones. The results show that methoprene accelerates sexual maturation of mass-reared A. obliqua males and increases their mating propensity. This would reduce the time required to attain sexual maturation by sterile males, thus decreasing fly handling costs and improving the efficacy of the sterile insect technique.

Sex Pheromone of Anastrepha striata.

The guava fruit fly, Anastrepha striata, is a pest of several cultivated species of Myrtaceae in the American tropics and subtropics. During calling, A. striata males release numerous volatiles. This study was conducted to identify which of the male volatiles function as the A. striata sex pheromone and to investigate the effects of age and time of day on the emission of pheromone components. Analysis of the volatiles from males collected by solid phase microextraction using gas chromatography coupled to electroantennographic detection (GC-EAD) showed that three volatile compounds elicited repeatable responses from the antennae of females. The EAD-active compounds were identified by GC/mass spectrometry as ethyl hexanoate, linalool, and ethyl octanoate. In two-choice tests using Multilure traps placed in field cages, traps baited with live males, ethyl hexanoate, or the three-component blend captured more females than unbaited traps. However, there was no difference in catches when traps baited with live males were compared against traps baited with ethyl hexanoate. Although traps baited with the three-component blend caught more females than traps baited with live males, the difference was not significant. Analyses of pheromonal components released by A. striata males 8 to 26 days old showed that there was an effect of age on pheromone production and also a significant effect of time of day on pheromone emission. Release of the volatile compounds occurred from 14.00 to 18.00 hr, although traces of linalool were detected from 08.00 hr. Peak emission of pheromone compounds occurred at 14.00 hr.

Chemical symphony: Unraveling triatomine aggregation and attraction patterns for innovative pest control solutions.

Aggregation is a spatial distribution pattern where individuals can be grouped through interaction with particular signals or cues [e.g., chemical substances]. Numerous triatomine species exhibit attraction and aggregation around both conspecific and heterospecific feces. It remains unclear whether compounds released by feces function as signals (pheromones or synomones) or cues. Employing a bioassay that mimics field conditions, we investigated the response of Triatoma pallidipennis bugs to volatiles present in its feces and blends of these compounds. Our findings indicate that short-chain aldehydes, namely nonanal, octanal, heptanal, and hexanal, attract fifth-instar nymphs. Furthermore, insects responded to individual compounds as well as secondary, ternary, and quaternary blends. The most attractive blend consisted of all four aldehydes. Additionally, quaternary blends at various compound ratios attracted fifth-instar nymphs of T. phyllosoma and T. longipennis. We discuss the potential roles of these compounds as signals or cues and explore their application as bait in control programs.

Gymnandrosoma aurantianum (Lepidoptera: Tortricidae): Calling Rhythm and Effect of Age on Female Sex Pheromone Titer and Male Antennal Responses.

The macadamia nut borer, Gymnandrosoma aurantianum Lima (Lepidoptera: Tortricidae), is the main pest of Macadamia integrifolia Maiden & Betche (Proteales: Proteaceae) in Central America. Despite its importance, there is little information on its reproductive behavior. We studied the calling behavior and effect of age on female sex pheromone production and male antennal response to the pheromone. Calling behavior of G. aurantianum females occurred at the onset of scotophase, between 17:00 and 20:00 h. The mean time spent calling was 64 min. It was observed that 30% of the 50 females exhibited a calling posture characterized by extrusion of the pheromone gland from the tip of the abdomen and they spread their wings slightly. Female age had no influence on the sex pheromone production, while male antennal response increased with age and pheromone dosage. The information obtained in this work contributes to understanding the sexual behavior of G. aurantianum and thus to the creation of strategies to control this important pest in macadamia.

Lessons to be popular: the chemical basis of aggregation in Trypanosoma cruzi-infected and non-infected Chagasic bugs.

Aggregation is one of the most remarkable behaviours in the animal kingdom-a process that is usually governed by pheromones. Triatomines are blood-sucking bugs that act as vectors of Trypanosoma cruzi, the etiological agent of Chagas disease in mammals, including humans. Triatomines usually gather in roosting refuges by using aggregation pheromones of unknown chemical structure. In terms of vector control, one option to reduce triatomine-human contact is via capturing the insects into traps baited with lures based on such aggregation pheromones. As a first step towards this aim, we elucidated the aggregation pheromone in the triatomine Triatoma pallidipennis, using T. cruzi-infected and non-infected bugs. We used different extraction techniques and gas chromatography coupled to mass spectrometry for the identification. Also, two different bioassays were implemented for evaluating the attractant and arrestant activity of the pheromone. We found that T. pallidipennis produced short-chain aldehydes as attractants, and nitrogen-derived compounds as arrestants. We detected differences in the production and perception of these compounds according to whether animals were infected or not. These findings show that T. cruzi may influence triatomine chemical ecology and are promising tools for triatomine control.

A baited trap for kissing bugs (Hemiptera: Reduviidae: Triatominae).

Chagas disease is a key vector-borne disease. This illness is caused by Trypanosoma cruzi Chagas, which is transmitted by triatomine bugs. Largely, the control of this disease relies on reducing such contact. We optimized the performance of a box trap in laboratory conditions to capture four triatomine species: Triatoma pallidipennis (Stål), Triatoma infestans Klug, Triatoma phyllosoma (Burmeister), and Rhodnius prolixus Stål. We varied four components for a box trap: material, color, height, and bait attractants. All species were captured more in corrugated cardboard traps than in other trap material. Moreover, T. infestans and R. prolixus were also captured in plywood traps. T. pallidipennis preferred traps of 15 × 15 × 4 cm and 20 × 20 × 4 cm, while T. phyllosoma and T. infestans were more captured in traps of 10 × 10 × 4 cm, and 15 × 15 × 4 cm. Rhodnius prolixus was more captured to 10 × 10 × 4 cm traps. T. pallidipennis was trapped with traps of any color tested, T. phyllosoma and T. infestans were captured more in red and yellow traps, and R. prolixus was mostly captured in blue, violet, and yellow traps. Triatoma pallidipennis was captured at any height above the ground, while T. phyllosoma, T. infestans, and R. prolixus were mostly captured 50, 100, and 150 cm above the ground. Regarding the lure, T. pallidipennis was trapped with four aldehydes + lactic acid + ammonia; T. infestans and R. prolixus were trapped with a blend of four aldehydes + lactic acid, a blend of the four aldehydes + ammonia, and a blend of four aldehydes + lactic acid + ammonia. Triatoma phyllosoma was trapped with any lure tested. These results showed that the trap boxes offer an alternative method for controlling Chagas disease.

Dog hair volatiles attract Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) females.

Rhipicephalus sanguineus sensu lato (s.l.) (Latreille) feeds on domestic dogs worldwide. This tick species uses dog volatiles during host-seeking behavior. In this study, we identified volatile compounds from dog hairs involved in the host location of R. sanguineus s.l. The R. sanguineus s.l. females, but not males, were attracted to hair samples and Super Q extracts from Schnauzer dogs in Y-tube olfactometer bioassays. A total of 54 compounds from dog hair extracts were identified by gas chromatography coupled to mass spectrometry, including hydrocarbons, aldehydes, alcohols, ketones, and carboxylic acids. Screening the identified compounds by the single sensillum recording technique showed that isovaleric acid, hexanal, heptanal, and sucaltone (6-methyl-5-hepten-2-one) significantly stimulated the olfactory receptor neurons of the basiconic, chaeticum, and trichodeum sensilla of female ticks. When synthetic compounds were evaluated alone, or in binary, tertiary, or quaternary mixtures, female ticks were only attracted to isovaleric acid and 1 tertiary mixture (hexanal, heptanal, and isovaleric acid). We conclude that isovaleric acid functions as an attractant for R. sanguineus s.l. These findings contribute to the understanding of the chemical ecology of ticks during host location.

Olfactory Responses of Anastrepha obliqua (Diptera: Tephritidae) to Mango Fruits as Influenced by Cultivar and Ripeness Stages.

Anastrepha obliqua Macquart (Diptera: Tephritidae) is a polyphagous species with hog plums (Spondias spp.) (Sapindales: Anacardiaceae) and mangoes (Mangifera indica L.) (Sapindales: Anacardiaceae) as primary host fruits. In this study, the olfactory preference of A. obliqua for three stages of ripeness of two mango cultivars ('Coche' and 'Ataulfo') was investigated. The female flies were more attracted to ripe 'Coche' fruits compared to those ripe 'Ataulfo'. Further, they were more attracted to the 'Coche' half-ripe and ripe fruits than to the unripe ones, but they did not discriminate among the stages of ripeness of 'Ataulfo' fruits. The male flies did not show preference for any specific mango cultivars or ripeness stage tested. Four compounds from ripe 'Coche' mangoes, and two from ripe 'Ataulfo' fruits were identified using coupled gas chromatography-electroantennographic (GC-EAD) recording and gas chromatography-mass spectrometry (GC-MS) analysis. 'Coche' mango volatiles eliciting responses from the female antennae were ethyl butyrate, ethyl hexanoate, ethyl heptanoate, and ethyl octanoate. The two 'Ataulfo' mango volatiles were identified as 3-carene and ethyl octanoate. These compounds were absent in unripe mangoes of both cultivars. Synthetic blends of these compounds were attractive to females as mango extracts in field cage tests. Our results suggest that the olfactory preference of A. obliqua for attractive hosts is based on the presence or absence of the compounds associated with fruit maturity.

Intraspecific variation of scent and its impact on pollinators' preferences.

Floral scents shape plant-pollinator interactions. Although populations of the same species can vary in their floral scent, little is known about how this variation affects pollinator visitation. In this study, we compare the scents emitted by buzz-pollinated Solanum rostratum (Solanaceae) in two areas of its distribution (Mexico and USA) and investigate how these differences in scent affect pollinator preferences and attraction. We determined the variation of floral volatile compounds using hexane extraction followed by gas chromatography coupled with spectrometry. We also performed a field cage multiple-choice bioassay and a Y-tube behavioural bioassay using Bombus impatiens. We recorded 13 volatile compounds in floral extracts for plants from both ranges that varied qualitative and semi-quantitatively among populations. We found that in the field cage experiment, bumble bees visited plants from the US populations more frequently than plants from Mexican populations. However, bees showed no difference in preference between extracts from Mexican or US flowers. We conclude that although bees show differential visitation to whole plants of different regions, variation in floral extract alone does not translate into differences in preference by B. impatiens. The potential effects of variation in floral scent on the other native bee pollinators remain to be assessed.

Queen volatiles as a modulator of Tetragonisca angustula drone behavior.

Tetragonisca angustula mating occurs during the virgin queen nuptial flight, usually in the presence of a drone congregation area (DCA). The presence of virgin queen pheromone is considered the trigger for DCA establishment, although this has not been demonstrated experimentally. We established meliponaries, in different habitats, with T. angustula virgin queens during the main drone reproduction period. Eight DCAs were observed in urban areas, and all established outside or near colonies containing at least one virgin queen. The accumulation of drones in the DCAs occurred from 08:00 to 18:00 h and over 3-35 days. The number of drones in DCAs ranged from 60 to 2,000. In field trials, drones were attracted to virgin queens and also, unexpectedly, to physogastric queens. Volatiles collected from both virgin and physogastric queens elicited strong electoantennogram (EAG) responses from drones. Virgin and physogastric queen volatiles were qualitatively similar, but quantitatively different, in chemical composition. The queen's abdomen was the principal source of these compounds. Isopropyl hexanoate (IPH), the most abundant compound in virgin queen volatiles and one of the most abundant in physogastric queen volatiles, was identified as one of the compounds that elicited EAG responses and was demonstrated to attract drones in a field test.

The Succession of Flies of Forensic Importance Is Influenced by Volatiles Organic Compounds Emitted During the First Hours of Decomposition of Chicken Remains.

After death, a series of primary reactions occur that produce volatile organic compounds (VOCs) that are released into the environment. In this study, we investigated if the succession of flies of forensic importance in the first hours after death is mediated by VOCs in order to better understanding of the ecology of necrophagous insects. In total, 685 adult insects (Diptera and Hymenoptera) were collected by traps baited with chicken remains at different decomposition times (0, 6, 12, 24, 36, or 48 h). Of the total of insects caught, individuals from six families of Diptera can be cataloged of forensic importance. The most abundant dipteran family was Piophilidae with 213 individuals, followed by Calliphoridae with 178 specimens. Of the total flies caught, 90% were females and the rest were males. Most of the caught females were categorized as gravid, which visited more often the decaying tissues compared to nongravid females. The abundance of the flies increased in the remains with a longer time of decomposition. Six VOCs emitted in different relative quantities were identified according to the decomposition time of the remains. An apparent association was observed between the emission of ρ-cresol with Lucilia eximia (Wiedemann), between the emission of phenol, dimethyl disulfide, and dimethyl trisulfide with Chrysomya rufifacies (Macquart), and between the emissions of indole with Cochliomyia macellaria (Fabricius).

Rat volatiles as an attractant source for the Asian tiger mosquito, Aedes albopictus.

Aedes albopictus is a vector of dengue, chikungunya, and dirofilariasis. Volatile compounds are crucial for mosquitoes to locate their hosts. This knowledge has allowed the identification of attractants derived from human odours for highly anthropophilic mosquito species. In this study, we used rats as a experimental model to identify potential attractants for host-seeking Ae. albopictus females. Porapak Q extracts from immature female rats were more attractive to Ae. albopictus females than those from mature and pregnant females, and males. Phenol, 4-methylphenol, 4-ethylphenol, and indole were identified compounds in male, immature, mature, and pregnant female extracts. There were quantitative differences in these compounds among the extracts that likely explain the discrepancy in their attractiveness. Ae. albopictus females were not attracted to the single compounds when was compared with the four-component blend. However, the binary blend of 4-methylphenol + 4-ethylphenol and the tertiary blend of 4-methylphenol + 4-ethylphenol + indole were as attractive as the four-component blend. In the field trials, BGS traps baited with the tertiary or quaternary blends caught more Ae. albopictus females and males than BGS traps without lures. This is the first laboratory and field study to identify compounds that mediate the attraction of Ae. albopictus to one of its hosts.

Field evaluation of potential fruit-derived lures for Anastrepha obliqua (Diptera: Tephritidae).

Previous studies have shown that a nine-component blend (ethyl butyrate, isopropyl butyrate, hexan-1-ol, propyl butyrate, isobutyl butyrate, ethyl hexanoate, isopentyl butyrate, ethyl benzoate, and ethyl octanoate) isolated from Spondias mombin L. (Anacardiaceae) fruit are attractive to both sexes of West Indian fruit fly, Anastrepha obliqua (Macquart) (Diptera: Tephritidae), in laboratory and field cage tests. In this study, we evaluated the effectiveness of traps baited with the nine-component blend in capturing wild A. obliqua in a mango, Mangifera indica L. variety Ataulfo) orchard. In addition, we tested other S. mombin-derived lures to determine whether any of these effectively mimic the nine-component blend in attracting A. obliqua. In all trials, we compared the attractiveness of the S. mombin-derived lures against hydrolyzed protein, the standard bait for monitoring A. obliqua. We found that, in some trials, there was no difference in the number of females caught by traps baited with the nine-component blend or with hydrolyzed protein. In other trials, traps baited with hydrolyzed protein captured more females than traps baited with the nine-component blend. For males, in general there were no differences in the number of flies caught by traps baited either with the nine-component blend or with hydrolyzed protein. Traps baited with other S. mombin-derived lures captured fewer A. obliqua than traps baited with hydrolyzed protein. Traps baited with S. mombin-derived lures caught fewer species of nontarget tephritid flies and nontarget insects than traps baited with hydrolyzed protein.

Olfactory response of the Mexican fruit fly (Diptera: Tephritidae) to Citrus aurantium volatiles.

We investigated the behavioral and electrophysiological responses of male and female Mexican fruit fly, Anastrepha ludens (Loew) (Diptera: Tephritidae), to volatiles of bitter orange fruit, Citrus aurantium L. In field cage tests, the number of A. ludens caught in Multilure traps baited with mature green bitter orange fruit was significantly higher than the number captured in traps baited with ripe yellow bitter orange fruit and control (unbaited traps). Both sexes were more attracted to mature green bitter orange fruit extracts than to controls in both flight tunnel and field cage assays. Gas chromatography-mass spectrometry analysis of the mature green bitter orange fruit volatiles identified 10 different compounds. Limonene was the most abundant volatile compound, followed by an unknown compound, tentatively identified as trans-ocimene. Linalool, beta-pinene, and methyl salicylate were found in lower proportions. Both sexes of A. ludens evoked higher antennal response to linalool, methyl salicylate, and to a blend of these four components in comparison with limonene, and beta-pinene. In flight tunnel, both sexes were more attracted and landed more often on spheres baited with the four-component blend compared with control spheres. In field cage tests, Multilure traps baited with the four-component blend captured significantly more A. ludens flies than traps baited with hydrolyzed protein or control traps.