South American Fruit Fly Research Articles

Molecular Markers for Analyses of Genetic Diversity within the Anastrepha fraterculus Complex with Emphasis on Argentine Populations.

The South American fruit fly Anastrepha fraterculus (Wiedmann) has a vast range extending from northern Mexico, through Central America, to South America where it is an extremely polyphagous pest of wild and cultivated fruits. It is a complex of cryptic species currently composed of eight recognised morphotypes: "Mexican", "Venezuelan", "Andean", "Peruvian", "Ecuadorian", and the three Brazilian morphotypes "Brazilian-1", "Brazilian-2", and "Brazilian-3". Molecular markers that can identify the member species of the complex are crucial for the implementation of effective pest control measures, such as the sterile insect technique. The object of this study was to evaluate the use of the internal transcribed spacer 2 (ITS2) sequence for discriminating several members of the A. fraterculus cryptic species complex (Mexican, Peruvian, and Brazilian-1) and a related species, Anastrepha schultzi Blanchard. The analysis highlighted significant genetic differentiation between the evaluated morphotypes, allowed their discrimination within the A. fraterculus cryptic species complex, and provided new insights into their genetic relationships. The ITS2 marker provides a basis for the development of taxonomic keys for the discrimination of the cryptic taxa within the A. fraterculus cryptic species complex. ITS2 also represents an important marker for the poorly studied species A. schultzi.

Volatiles of essential oils and yeast derivatives influence mating behaviour of Anastrepha fraterculus males under field cage conditions

AbstractThe sterile insect technique (SIT) is used for the management of tephritid fruit fly pests. The South American fruit fly, Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae), is one potential pest to be targeted by means of SIT. The success of SIT depends, to a large extent, on the sexual performance of sterile males. Various approaches have been evaluated with the aim of improving their sexual performance. These include the exposure to plant‐derived compounds and/or the provision of protein sources in the adults' diet capable of stimulating male mating success. The present study aimed to determine whether exposure to volatiles of Citrus limon (L.) Burm. F. (Rutaceae) essential oil and limonene confers a mating advantage to A. fraterculus laboratory males fed two distinct dietary regimes when competing with wild males for wild females under field cage conditions. Dietary regimes were, one, with non‐hydrolysed brewer's yeast and sugar (1:3 ratio), and the other with brewer's yeast hydrolysate enzymatic and sugar (1:12 ratio). The effect was evaluated in four variables associated with mating success: number of copulas obtained, latency to mate, copula duration, and copula location. Exposure to volatiles did not affect the number of matings achieved, irrespective of the diet given to the males. When laboratory males were fed with brewer's yeast hydrolysate, the effect of volatile exposure was shown in latency to mate, copula duration, and copula location. When the laboratory males were fed with non‐hydrolysed brewer's yeast, the effect of volatile exposure was shown only in copula duration. Laboratory males fed brewer's yeast hydrolysate achieved the same number of matings as wild males, whereas laboratory males fed non‐hydrolysed brewer's yeast had lower performance.

Male exposure to guava volatiles affects female remating behavior in Anastrepha fraterculus

AbstractPlant‐derived volatiles can have positive or negative effects on insects. Exposure to volatiles of guava (Psidium guajava L.) (Myrtaceae) enhances male mating success in the South American fruit fly, Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae), an important pest of various fruits. These volatiles can therefore be used as a post‐teneral, pre‐release supplement in sterile insect technique (SIT) programs. In SIT, mass‐reared sterile males compete for and mate with wild females, in order to reduce populations of insect pests. However, the success of SIT will be diminished if males are not able to inhibit females from remating with other (potentially wild) males. Here, we investigated the remating propensity of A. fraterculus females mated with males exposed to guava volatiles or non‐exposed (control) in choice and no‐choice tests. In addition, we tested whether exposure to guava volatiles affected male reproductive organ size (testes, accessory glands, and seminal vesicles) and cuticular hydrocarbon (CHC) profile. Females mated with guava‐exposed males were more likely to remate than females mated with control males, but there was no difference in the length of the refractory period (i.e., the time between the first and second mating event). Reproductive organ size did not differ between exposed and non‐exposed males, but exposed males had a higher quantity of waxes than non‐exposed males, and CHC profiles differed. The results are discussed in the context of SIT programs for the control of this insect pest.

Behavioural and Electrophysiological Response of Anastrepha fraterculus (Diptera: Tephritidae) to a γ-Lactone Synthetic Semiochemical.

Attractants are a powerful tool for pest management. The lack of specific attractants for the South American fruit fly, Anastrepha fraterculus, a complex of cryptic species of great economic importance in South America, makes it difficult to monitor the pest in the field. The γ-lactone male sex and aggregation pheromones of several Anastrepha species, naturally released in a 7:3 epianastrephin to anastrephin ratio, and a structurally related naturally occurring γ-lactone ((±)-trans-tetrahydroactinidiolide) with gem-dimethyl groups (dimethyl) at C(4), were evaluated as potential attractants of this species. Different age and mating conditions of A. fraterculus males and females were evaluated during electroantennography (EAG) and field cage experiments in which polymeric lures were deployed to contain 100 mg of attractant. Epianastrephin and dimethyl were EAG+ for all fly conditions, with epianastrephin eliciting the highest response for both sexes and immature flies showing greater responsiveness than mature flies. In the field cage experiments, immature flies were only attracted to leks; virgin females were attracted to leks, dimethyl, and both epianastrephin-anastrephin formulations (95 and 70 wt.% epianastrephin); mature-mated males were attracted to leks, dimethyl and 70 wt.% epianastrephin; and mature-mated females were only attracted to leks. Our bioassays showed a promising performance of the analog dimethyl since it elicited the same response as epianastrephin, requires fewer steps to synthesize, and contains one less chiral center than the natural pheromones. The attraction to leks was recorded for all mating conditions and ages of flies and suggests that air-borne volatiles of calling males contain cues that could act as sensory traps. The addition of any of these compounds in the synthetic attractants may result in a greater attraction and thus deserves further evaluation. Dose-response experiments will provide additional information to move a step forward and validate the results obtained in open-field conditions.

Methoprene treatment and its effect on male reproductive organ size and female remating in a fruit fly.

Methoprene, a juvenile hormone analog, is used to accelerate sexual maturation in males of species of economic importance in support to the sterile insect technique (SIT). In the SIT, mass-reared sterile males are released into the field and need to survive until they reach sexual maturation, find a wild female, mate with her and then induce female sexual refractoriness, so she will not remate with a wild counterpart. The use of methoprene shortens the time between release and copulation. However, in South American fruit flies, Anastrepha fraterculus, the ability of methoprene-treated males to inhibit female remating has been shown to be lower than wild males, when methoprene was applied by pupal immersion or topical application. Here we evaluated the possibility of incorporating methoprene into the male diet at different doses and the ability of those males to inhibit female remating, as well as the effect of methoprene on male reproductive organ size, due to the possible correlation between male accessory gland size and their content, and the role of male accessory gland proteins in female inhibition. We found that A. fraterculus males fed with methoprene in the adult protein diet at doses as high as 1% were less likely to inhibit female remating, however, at all other lower doses males had the same ability as untreated males to inhibit female remating. Males fed with methoprene had bigger male accessory glands and testes compared to methoprene-deprived males. We demonstrate that the incorporation of methoprene in adult male diets is possible in this species and potentially useful as a post-teneral, pre-release supplement at doses as low as 0.01%. Even at higher doses, the percentage of females remating after 48 h from the first copulation is sufficiently low in this species so as not compromise the efficiency of the SIT.

Natural parasitism in fruit fly (Diptera: Tephritidae) and interaction with wild hosts surrounding apple orchards adjacent to Atlantic Forest fragments in Paraná State, Brazil.

The South American fruit fly, Anastrepha fraterculus (Wiedemann, 1830) (Diptera: Tephritidae), is an important pest in the subtropical region of Brazil. This insect has tritrophic relation between wild fruits and parasitoids and is associated with apple (Malus domestica Borkh.) orchards adjacent to the Atlantic Forest in Paraná. We thus investigated the degree of infestation of the fruit fly and natural parasitism in wild and cultivated fruits surrounding apple orchards. For this purpose, we collected fruits of Acca sellowiana (Berg.) Burret, Campomanesia xanthocarpa (Mart), Eugenia uniflora L., Eugenia pyriformis Cambessèdes, Psidium cattleianum Sabine, Psidium guajava (L.), Annona neosericea Rainer and Eriobotrya japonica (Thumb) in apple orchards adjacent to the Atlantic Forest located in Campo do Tenente, Lapa and Porto Amazonas counties. In total, we collected 18,289 fruits during four growing years. The occurrence of A. fraterculus depends on the susceptible period of apple fruits. A. sellowiana and P. cattleianum were considered primary fruit fly multipliers and P. guajava was secondary, all occurring after the apple harvest (IS period). The group of parasitoids with A. fraterculus was Aganaspis pelleranoi (Brèthes, 1924) (Hymenoptera: Figitidae), Opius bellus (Gahan, 1930), Doryctobracon areolatus (Szépligeti, 1911) and Doryctobracon brasiliensis (Szépligeti, 1911) (Hymenoptera: Braconidae) all of which are first records in the Atlantic Forest in Paraná. First record of O. bellus occurring in the State of Paraná, as well as, first record of the tritrophic association between host plant A. neosericea, parasitoids D. areolatus and O. bellus and fruit fly A. fraterculus. The host P. cattleianum stood out among the Myrtaceae species in regard to the high diversity of parasitoid species (81% of parasitoids). The total number of Figitidae species (76.5%) was higher than that of Braconidae species. The influence of climatic events in southern Brazil on wild fruit production should be further studied to understand the association of A. fraterculus with the tritrophic relationship.

Double minute chromosomes in Anastrepha fraterculus (Wiedemann) (DIPTERA: Tephritidae): a model for cancer studies

Anastrepha fraterculus (Wied.) is known as the South American Fruit Fly. In order to develop efficient control strategies, we need deep knowledge on its biology along with periodical studies on population dynamics. Citogenetic studies on natural populations of this pest fly made it possible to reveal the presence of double minute chromosomes (DMs) in several natural populations of this insect. Cytogenetic studies performed in our insect laboratory, allowed the genetic analysis through a genealogical methodology. The establishment of families made it possible the genetic studies allowing the rigorous identification, characterization and confirmation of new chromosomal variants, frequently missinterpreted when the materials analyzed only come from nature. Double minute chromosomes -considered a type of chromosomal rearrangement- are extra chromosomal gene copies. This study sought to answer: What role do DMs chromosomes play in laboratory populations of the pest derived from natural populations? How are they transmitted from one generation to another? To answer our questions, we analyzed for 25 generations, two laboratory populations derived from Tucuman (T) and Buenos Aires (BA -tester) guava,. Data were recovered from cytological analysis of ganglia preparations revealed with H33258. The natural population from BA didn’t carry DMs. Results showed DMs in flies of both laboratory populations. DMs were transmitted from parents to progenies through 25 generations and their transmission was randomized in number. DMs are the cytological expression of resistance mechanisms used by the pest as a response to environmental stress. DMs in BA strain marked the change to the laboratory environment. A. fraterculus is a model insect for the study of cancer.

EFICIÊNCIA DE ATRATIVOS ALIMENTARES NA CAPTURA E NO MONITORAMENTO DE MOSCA-DAS-FRUTAS SUL-AMERICANA EM POMAR DE PEREIRA ASIÁTICA

ABSTRACT The South American fruit fly, Anastrepha fraterculus (Diptera: Tephritidae) is the most important insect pest in pear tree crops in Southern Brazil. Several studies pointed to the controversial efficacy of some food lures used for capture and monitoring this species in various fruit species. This study aimed to evaluate the efficacy of food lures available in the Brazilian market in capturing and monitoring A. fraterculus in relation to grape juice. The experiment was conducted during the 2014/2015 and 2015/2016 crop seasons in an Asian pear (Pyrus spp.) orchard located in Caçador, State of Santa Catarina, Brazil. The food lures evaluated were CeraTrap®, BioAnastrepha®, Torula®, Isca Mosca®, BioFruit®, and grape juice (a standard food lure in Southern Brazil). For each attractant substance, population fluctuations of A. fraterculus were recorded as well as the average number of female and male specimens captured, the FTD (fly/trap/day) rate of capture, the number of control indications, and mean weekly evaporation. The first A. fraterculus adults were captured in November, and in both crop seasons the population peak was found in January. CeraTrap® was more effective in capturing females and males and indicated a higher number of control indications compared to the other food lures. Grape juice presented lower effectiveness compared to CeraTrap®, including the evaporation parameter. It was concluded that CeraTrap® is the most effective food attractant in capturing adults of A. fraterculus and more accurate in detecting its population levels in Asian pear orchards, therefore, it is recommended rather than the usual grape juice.

Use of mineral particle film to protect ‘Okitsu’ tangerine and ‘Valencia’ orange against Anastrepha fraterculus and the effect on fruit quality

The particle film technology has been reported as a promising tool in pest control. The objective of this work was to evaluate the efficiency of kaolin-based products against the oviposition of South American fruit fly, Anastrepha fraterculus (Dip.:Tephritidae), and its effect on the quality of citrus fruits. The experiment was conducted in orchards of ‘Okitsu’ tangerine and ‘Valencia’ orange trees in the 2017, 2018 and 2019 harvests. The treatments were as follows: 1) kaolin 10% + 0.1% Break-Thru® adjuvant; 2) Surround® 5% WP; 3) 0.15% phosmet (Imidan® 500 WP), 75 g. a.i.; 4) without application (control). The sprays were performed every 21 days. At harvest, fruits were individually packed in a greenhouse for inspection after 25 days and infestation was recorded. Fruit samples were evaluated for average diameter, average mass, soluble solids, titratable acidity and peel colorimetry. Infestation of A. fraterculus in tangerines was reduced in plants treated with the two kaolin-based products in the 2017 harvest. In the 2017 and 2019 crops, Surround® WP reduced the infestation and the number of puparium/fruits in oranges. The mineral films did not alter the physicochemical characteristics of the fruits, representing a promising alternative for the management of A. fraterculus.

Fine Scale Microevolutionary and Demographic Processes Shaping a Wild Metapopulation Dynamics of the South American Fruit Fly Anastrepha fraterculus.

Anastrepha fraterculus (Wiedmann)is an important American pest species. Knowledge of its population dynamics is of particular interest for ecology, evolutionary biology, and management programs. In the present study, phenotypic, genotypic, and spatial data were combined, within the frame of landscape genetics, to uncover the spatial population genetic structure (SGS) and demographic processes of an Argentinian local population from the Yungas ecoregion. Eight simple sequence repeats (SSR) loci and six morphometric traits were analysed considering the hierarchical levels: tree/fruit/individual. Genetic variability estimates were high (HE = 0.72, RA = 4.39). Multivariate analyses of phenotypic data showed that in average 52.81% of variance is explained by the tree level, followed by between individuals 28.37%. Spatial analysis of morphological traits revealed a negative autocorrelation in all cases. SGS analysis and isolation by distance based on SSR showed no significant autocorrelation for molecular coancestry. The comparison between phenotypic (PST) and molecular (FST) differentiation identified positive selection in different fruits for all traits. Bayesian analysis revealed a cryptic structure within the population, with three clusters spatially separated. The results of this study showed a metapopulation dynamics. The genetic background of the components of this metapopulation is expected to change through time due to seasonality, repopulation activities, and high gene flow, with an estimated dispersal ability of at least 10km. Effective population size (Ne) of the metapopulation was estimated in around 800 flies, and within subpopulations (clusters) Ne was associated with the levels of genetic drift experienced by the founding lineages.

Anastrepha fraterculus (South American fruit fly)

Anastrepha fraterculus (South American fruit fly)

Phenological development of fruits in cultivars of feijoa (Acca sellowiana) and its relationship with South American fruit fly infestation

ABSTRACT: The present study aimed to evaluate the developmental phases of feijoa fruits associated with infestation by Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) and the nonpreference of fruit flies for ripe fruits of feijoa. Two tests were carried out. In the first trial, we evaluated the association between the developmental stages of feijoa fruits and infestation by A. fraterculus. To accomplish this, fruits at five different stages of development, from green to ripe, were examined from the Alcântara cultivar. In the second trial, we evaluated the nonpreference of A. fraterculus for ripe fruits of Alcântara, Helena, Mattos and access 2316 cultivars. Physicochemical analyses were performed on the fruits of both trials. In the second test, analyses of polyphenol index and tannin concentration were also performed. Feijoa fruits in stage I are the likely targets of attack by A. fraterculus. The fruits of Alcântara cultivar from stage II, with 39 mm of transversal diameter and soluble solids, presented four puparium / fruit. The fruits of Alcântara and access 2316 cultivars showed greater and lesser infestation, respectively. The fruits of access 2316 also showed a higher concentration of tannins compared to the three commercial cultivars tested, which may have conferred the greatest protection against infestation by A. fraterculus. Feijoa fruits from Alcântara and Mattos cultivars showed high susceptibility to infestation by A. fraterculus, requiring management practices to guarantee commercial production.

Magnetite nanoparticles as a promising non contaminant method to control populations of fruit flies (DIPTERA: Tephritidae)

“True fruit flies” belong to the family Tephritidae. Among them, the Mediterranean fruit fly (Medfly) Ceratitis capitata (Wiedemann) is the most economically important agricultural pest insect in the world. Anastrepha fraterculus (Wiedemann) is the South American fruit fly and represents a serious problem for countries of America. Both species share hosts fruits. Traditionally the control of fruit flies bases on the use of pesticides with chemical components. Due to their massive use to crops, pesticides are associated to environmental pollution and toxicity in mammals. An emerging technology is the use of nanomaterials with pesticidal activity or for the delivery of pesticides. The present paper reports: a) the synthesis of iron oxide (magnetite) nanoparticles and b) the effects of Fe3O4 nanoparticles during the development of the tephritid flies C. capitata and A. fraterculus. We sampled guava fruits to recover immature stages of fruit flies. Magnetite nanoparticles Fe3O4 were synthesized by co-precipitation of Fe (III) and Fe (II). We suspended doses of 100, 200 and 400 µg/ml of magnetite nanoparticles in water and we added the suspensions to larval medium. NPs are spherical with a medium diameter of 11 ± 2 nm and unimodal size distribution. During larval-pupal development, we checked out difficulties in the capacity to complete the natural biological cycle. Only 40% of larvae feeded in medium 400 μg / ml Fe3O4 NPs were able to continue their life cycle, in contrast to 92% of the control. Application of iron oxide (or magnetite) nanoparticles to larval food resulted in larvae toxicity expressed as dose-dependent lethality

Improvement of the Mass-Rearing Protocols for the South American Fruit Fly for Application of the Sterile Insect Technique.

Simple SummarySignificant advances in the domestication and artificial rearing techniques for the South American fruit fly, Anastrepha fraterculus (Diptera, Tephritidae), have been achieved since the FAO/IAEA Workshop held in 1996 in Chile. Despite the availability of rearing protocols that allow the production of a high number of flies, they must be optimized to increase insect yields and decrease production costs. In addition, evidence of sexual incompatibility between a long-term mass-reared Brazilian strain and wild populations has been found. To address these issues, this study refined rearing protocols and assessed the suitability of a bisexual A. fraterculus strain established from a target population in southern Brazil for the mass production of sterile flies.The existing rearing protocols for Anastrepha fraterculus must be reviewed to make economically viable the production of sterile flies for their area-wide application. Additionally, evidence of sexual incompatibility between a long-term mass-reared Brazilian strain and wild populations has been found. To address these issues, this study aimed to refine rearing protocols and to assess the suitability of an A. fraterculus strain for the mass production of sterile flies. A series of bioassays were carried out to evaluate incubation times for eggs in a bubbling bath and to assess the temporal variation of egg production from ovipositing cages at different adult densities. A novel larval diet containing carrageenan was also evaluated. Egg incubation times higher than 48 h in water at 25 °C showed reduced larval and pupal yields. Based on egg production and hatchability, the density of 0.3 flies/cm2 can be recommended for adult cages. The diet with carrageenan was suitable for mass production at egg-seeding densities between 1.0 and 1.5 mL of eggs/kg of diet, providing higher insect yields than a corn-based diet from Embrapa. Even after two years of being reared under the new rearing protocols, no sexual isolation was found between the bisexual strain and wild flies.

Determining the Sterilization Doses under Hypoxia for the Novel Black Pupae Genetic Sexing Strain of Anastrepha fraterculus (Diptera, Tephritidae).

Simple SummaryThe sterile insect technique is an environmentally-friendly method that can be used to manage populations of the South American fruit fly Anastrepha fraterculus, but its sterilizing doses have been determined only under normoxia. To maintain sterile male fly quality without jeopardizing sterility, a strategy of applying the radiation dose under an oxygen-reduced atmosphere is commonly used. Therefore, this study tested a range of gamma radiation doses under hypoxia on pupae from a bisexual strain and a novel genetic sexing strain (GSS) of A. fraterculus. Four types of crosses between irradiated flies under hypoxia and nonirradiated flies of the bisexual strain were set to assess sterility for each strain and radiation dose. For males from both strains, the effect of radiation dose on the percentage of egg hatch, egg-to-pupa recovery, and recovery of adults were determined. A dose of 74 Gy reduced egg hatch by 99% regardless of the male strain and was considered the sterilizing dose. The fertility of irradiated females and development of their offspring were severely affected, even at low doses under hypoxia, and no eggs were laid with doses above 50 Gy.A common strategy used to maintain sterile fly quality without sacrificing sterility is to irradiate the insects under an oxygen-reduced atmosphere. So far, sterilizing doses for the South American fruit fly Anastrepha fraterculus have only been determined under normoxia. Our study reports for the first time the dose-sterility response under hypoxia for two different A. fraterculus strains. The pupae were derived from a bisexual strain (a Brazilian-1 population) and a recently developed genetic sexing strain (GSS-89). Two hours prior to irradiation, pupae were transferred to sealed glass bottles and irradiated when oxygen concentration was below 3%. Four types of crosses with nonirradiated flies of the bisexual strain were set to assess sterility for each radiation dose. For males from both strains, Weibull dose–response curves between radiation doses and the proportion of egg hatch, egg-to-pupa recovery, and recovery of adults were determined. The GSS males revealed high sterility/mortality levels compared to males from the bisexual strain at doses < 40 Gy, but a dose of 74 Gy reduced egg hatch by 99% regardless of the male strain and was considered the sterilizing dose. The fertility of irradiated females was severely affected even at low doses under hypoxia.

Use of toxic bait to manage the south american fruit fly in apple orchards in Southern Brazil

Abstract Anastrepha fraterculus the South American fruit fly, is an important insect pest in apple orchards of southern Brazil, especially in small farms, where it often causes total crop loss. Experiments were conducted to evaluate, during four crop seasons (2009/2010, 2010/2011, 2012/2013, and 2013/2014) in organic and conventional apple orchards in southern Brazil, the toxic bait formulation ANAMED™ (oils and waxes 49.0% + M7 attractant 24.2% + spinosad insecticide 0.1%) for its capacity to reduce the South American fruit fly population. ANAMED applications started after apples with an average diameter of 20 mm had been thinned, and they were made every 14 days until harvest. ANAMED was sprayed on non-crop vegetation growing on the edges of the orchards at a rate of 1.0 kg.ha-1. Adult fruit flies were monitored weekly using McPhail traps baited with Torula™ yeast. Injured fruits were evaluated seven days before harvest. ANAMED reduced the adult population of trapped fruit flies captured in all crop seasons and the injured fruit, except for the first year of evaluation (2009/2010). In conclusion, the sequential use of ANAMED toxic bait over time significantly reduced adult populations of A. fraterculus and the percentage of fruits injured by this pest.

Lemon and Schinus polygama essential oils enhance male mating success of Anastrepha fraterculus

AbstractThe sterile insect technique (SIT) is an environmentally friendly pest control method that relies on the introduction of sterility into the pest population by the release of sterile males. Many Tephritidae fruit fly pests are currently being controlled with SIT. Sterile insect technique efficacy can be increased if the sexual success of mass‐reared sterile males is enhanced. Phytochemicals influence the sexual behaviour of many species of phytophagous insects. Here, we evaluated the possibility of using essential oils to enhance male sexual success of the highly polyphagous fruit fly pest Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae), also known as the South American fruit fly. In laboratory tests, we determined the effect of exposing males to volatiles from seven essential oils [Baccharis spartioides (Hook. &amp; Arn) Cabrera (Asteraceae), Schinus polygama (Cav.) Cabrera, Schinus areira (L.) (Anacardiaceae), Zingiber officinale (Roscoe) (Zingiberaceae), Citrus limon (L.) Burm. F., Citrus paradisi Macfad., and Citrus sinensis (L.) Osbeck (Rutaceae)] and two monoterpenes (limonene and citral) that are present at high proportions in some of the oils we evaluated. One exposed and one non‐exposed (control) male were placed in a mating arena with one virgin female. We recorded the type of male chosen as mating partner, copula start time, and copula duration. Laboratory males exposed to the volatiles of C. limon and S. polygama essential oils achieved more matings than non‐exposed males. The rest of the oils had no effect on male mating success. In addition, limonene‐exposed males obtained significantly more matings than non‐exposed males, and citral induced a detrimental effect. Exposure to the volatiles of the various essential oils and monoterpenes did not impact on copula start time and copula duration. We discuss the role of essential‐oil volatiles on A. fraterculus males’ sexual behaviour and its implications for SIT.

Identification and in situ hybridization to mitotic chromosomes of a molecular marker linked to maleness in Anastrepha fraterculus (Wied.)

The present report shows the molecular identification, isolation and citologically localization of a DNA-sequence from the South American fruit fly Anastrepha fraterculus (DIPTERA: Tephritidae) involved in sex- determination. It belongs to the Tephritidae family, the true fruit flies which are consider a pest of fruit crops. The sex determination system is of vital importance in the genetic control of the fruit fly pest: Sterile Insect Technique which unlike chemical control tactics, is environmentally friendly and does not pose any health concerns. We used in situ hybridization on mitotic chromosomes for localizing the primary sex determination factor in this fruit fly pest. Our results show that in Anastrepha fraterculus the Y chromosome is responsible for sex determination

Development and characterization of a pupal-colour based genetic sexing strain of Anastrepha fraterculus sp. 1 (Diptera: Tephritidae)

BackgroundArea-wide integrated pest management programs (AW-IPM) incorporating sterile insect technique (SIT) have been successful in suppressing populations of different fruit fly species during the last six decades. In addition, the development of genetic sexing strains (GSS) for different fruit fly species has allowed for sterile male-only releases and has significantly improved the efficacy and cost effectiveness of the SIT applications. The South American Fruit Fly Anastrepha fraterculus (Diptera: Tephritidae) is a major agricultural pest attacking several fruit commodities. This impedes international trade and has a significant negative impact on the local economies. Given the importance of sterile male-only releases, the development of a GSS for A. fraterculus would facilitate the implementation of an efficient and cost-effective SIT operational program against this insect pest species.ResultsFor potential use in a GSS, three new morphological markers (mutants) were isolated in a laboratory strain of A. fraterculus sp. 1, including the black pupae (bp) gene located on chromosome VI. The black pupa phenotype was used as a selectable marker to develop genetic sexing strains by linking the wild type allele (bp+) to the Y-chromosome -via irradiation to induce a reciprocal Y-autosome translocation. Four GSS were established and one of them, namely GSS-89, showed the best genetic stability and the highest fertility. This strain was selected for further characterization and cytogenetic analysis.ConclusionsWe herein report the development of the first genetic sexing strain of a major agricultural pest, A. fraterculus sp. 1, using as a selectable marker the black pupae genetic locus.

Larvicidal and Adulticidal Activities of Neem Oil against Anastrepha fraterculus (Wied.) (Tephritidae)

In the laboratory, a neem oil-based formulation was evaluated for its insecticidal potential against the South American fruit fly Anastrepha fraterculus (Wied.), as efficient alternative for growers harvest fruits more harmless for the human consumption. The commercial product was evaluated against eggs in vitro, guavas infested with eggs and young larvae, and adults. The application of 0.8% neem oil significantly reduced the larval hatching of A. fraterculus. Neem oil at 0.4, 0.6 and 0.8% significantly reduced the number of pupae and adults per fruit infested with eggs. Guava infested with A. fraterculus eggs and treated with neem oil at 0.8% exhibited a reduction of 90.0% and 92.6% of pupae and adults per fruit, respectively. The same dosage to guava infested by larvae achieved a 44.6 and 51.4% reduction of pupae and larvae, respectively. At 360 minutes after treatment, 0.8% of neem oil provided 67.9% of corrected adult mortality. This double insecticidal effect of neem oil and lack of phytotoxicity in ripe guavas at the tested concentrations demonstrate its potential in biorational management.