Parasitóides de moscas-das-frutas (Diptera: Tephritidae) associados a fruteiras tropicais

Interference of tritrophic (grape × medfly × parasitoid) interactions by mineral and biomaterial films

Fruit fly infestation is one of the main obstacles to the exportation of fresh agricultural produce. Films of mineral particles and biomaterials have the potential to protect fruits against tephritid fruit fly infestation. The present study evaluated the effects of particle films on the tritrophic interactions of grape (Vitis vinifera L.), the fruit fly Ceratitis capitata (Wiedemann) and the parasitoid Diachasmimorpha longicaudata (Ashmead) under semi-field conditions. Grapes were biometrically characterised (i.e. colour, firmness, mass, length and diameter), treated with mineral particles, biomaterials or distilled water (control), and then used in oviposition and parasitism bioassays. In the oviposition bioassay, the treated grapes were exposed to 50 C. capitata pairs in field cages, and after 48 h, the punctures and eggs on each fruit were counted. In the parasitism bioassay, treated grapes were artificially infested with third-instar C. capitata larvae (two per fruit), exposed (2 h) to 50 D. longicaudata pairs in field cages to determine parasitism index, larval and pupal viabilities and number of flies and parasitoids emerged. Treatment with the mineral film affected fruit colour and reduced C. capitata oviposition but failed to significantly affect the parasitism capacity of D. longicaudata. The ability of the parasitoid to locate and parasitise C. capitata larvae in kaolin-coated fruits suggests that kaolin films could be used in conjunction with biological agents to control fruit flies.

Does Diachasmimorpha longicaudata (Hymenoptera: Braconidae) have a preferential instar to parasitize Tephritidae (Diptera)?

ABSTRACT Diachasmimorpha longicaudata (Ashmead, 1905) is a koinobiont parasitoid of Tephritidae larvae, the third instar larvae of which is considered preferential, but it is able to parasitize other larval stages and compete with native parasitoids. This study investigated the preference and parasitism capacity of D. longicaudata in larvae of different instar of Anastrepha fraterculus (Wiedemann, 1830) (AF) and Ceratitis capitata (Wiedemann, 1824) (CC). The experiments were carried out under laboratory conditions, one instar being offered at a time in parasitism units, with the following choices among the hosts: 25 AF larvae and 25 CC larvae (first, second and third instar were evaluated). The other test was a multiple-choice in relation to the instar, for larvae of the same host species, with three parasitism units being offered, with 15 larvae of each instar. The mean number of formed pupae, emerged parasitoids, parasitized pupae, unviable pupae and sex ratio were evaluated. In the first bioassay, the mean number of emerged parasitoids and parasitized pupae in the AF host were significantly higher in treatments with first and second instar larvae. For CC there was no difference between the instars tested. In the second bioassay, the mean value of emerged parasitoids and parasitized pupae, was higher in second and third instar larvae for CC, and for AF was in second instar larvae. The sex ratio was biased for males in all treatments in both bioassays. The results show that D. longicaudata can parasitize and be successful in all available larval instars, being able to compete with parasitoids of any instar.

Strategies for Establishing a Rearing Technique for the Fruit Fly Parasitoid: Doryctobracon brasiliensis (Hymenoptera: Braconidae)

Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) is the most important pest in South American orchards. When control measures are not adopted, this pest can cause losses of up to 100%. Doryctobracon brasiliensis (Szépligeti) (Hymenoptera: Braconidae) is a larval-pupal endoparasitoid that can be used as a native biological control agent against A. fraterculus. This study aimed to develop a rearing technique for D. brasiliensis in larvae of A. fraterculus. Trials were carried out to: 1) determine the optimal instar for parasitism, 2) define the exposure time of larvae to parasitoids, 3) determine the density requirements of A. fraterculus larvae offered to each parasitoid, and 4) evaluate the effect of diet on adults of D. brasiliensis. In all trials, we evaluated the number of offspring, parasitism rate, and sex ratio. Moreover, in the experiment to investigate the effects of diet, we determined the longevity of males and females. In both choice and nonchoice parasitism tests, the parasitoids preferred third-instar larvae of A. fraterculus over second- and first-instar larvae. An exposure time of 12 h of A. fraterculus larvae produced larger numbers of parasitoids and higher parasitism rates. The density of 15 larvae of A. fraterculus to each female of D. brasiliensis produced a larger number of offspring. A supply of honey solution (20 and 50%) to the parasitoids yielded the highest number offspring and resulted in greater longevity. Our findings can be used to support the development of a mass rearing protocol for D. brasiliensis.

Irradiation of Anastrepha fraterculus (Diptera: Tephritidae) Eggs to Inhibit Fly Emergence in the Mass-Rearing of Diachasmimorpha longicaudata (Hymenoptera: Braconidae)

As the incidence of Anastrepha fraterculus (Wiedemann) has increased in Southern Brazil in the past 3 yr, an initiative to release sterile flies and parasitoids has started. In order to make feasible the mass-rearing of the parasitoid Diachasmimorpha longicaudata (Ashmed), this study investigated the suitability of A. fraterculus larvae derived from irradiated eggs as host for D. longicaudata Two different ages of A. fraterculus eggs (24 and 48 h old) were analyzed for hatchability after the exposure to a range of radiation doses. The hatchability of 48-h-old eggs was not affected by radiation, and no fly emerged at doses higher than 27.5 Gy. The larvae derived from irradiated eggs proved to be suitable hosts for the parasitoid development, with observed parasitism rates higher than 70% and sex ratio values above 0.6. The parasitism capability and longevity of D. longicaudata reared on larvae derived from irradiated eggs were also assessed. During the 10 d of parasitism evaluated, D. longicaudata from the treatments were able to parasitize nonirradiated larvae similarly as the parasitoids from controls and the laboratory colony. The longevity of D. longicaudata from the treatments was not affected either, with survival rates higher than 80% after 20 d of evaluation. The age of 48 h and a dose of 30 Gy could be considered the best age and dose for A. fraterculus eggs to be used in the mass-rearing of D. longicaudata The results of this study will decrease the costs of mass-rearing D. longicaudata on A. fraterculus.

Basis for the Development of a Rearing Technique of Aganaspis pelleranoi (Hymenoptera: Figitidae) in Anastrepha fraterculus (Tephritidae: Diptera)

Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) is among the most important pests of fruit trees in South America, where it can cause losses of up to 100% in fruit orchards. The endoparasitoid Aganaspis pelleranoi (Brèthes) (Hymenoptera: Figitidae) is one of the main natural enemies of A. fraterculus in Neotropical countries and can be used as a biological control agent against this pest. This study aimed to provide background biological information for the development of a method for mass rearing of A. pelleranoi in larvae of A. fraterculus . We determined the effects of diet on the longevity and parasitism capacity of A. pelleranoi adults, the optimal instar of A. fraterculus for parasitism, the ideal exposure time of the larvae to the parasitoid, and the parasitism capacity of females of A. pelleranoi . The results showed that a 30% honey:water solution maximized parasitoid longevity. Third-instar larvae of A. fraterculus should be used in parasitoid multiplication. An exposure time of 4 h of A. fraterculus larvae produced a larger number of parasitoid offspring, with the highest proportion of females. In addition, the estimated mean parasitism capacity of females of A. pelleranoi was 10 larvae per day. This information can help to develop a mass-rearing method for A. pelleranoi in larvae of A. fraterculus .

Augmentative Biological Control Using Parasitoids for Fruit Fly Management in Brazil

The history of classical biological control of fruit flies in Brazil includes two reported attempts in the past 70 years. The first occurred in 1937 when an African species of parasitoid larvae (Tetrastichus giffardianus) was introduced to control the Mediterranean fruit fly, Ceratitis capitata and other tephritids. The second occurred in September 1994 when the exotic parasitoid Diachasmimorpha longicaudata, originally from Gainesville, Florida, was introduced by a Brazilian agricultural corporation (EMBRAPA) to evaluate the parasitoid's potential for the biological control of Anastrepha spp. and Ceratitis capitata. Although there are numerous native Brazilian fruit fly parasitoids, mass rearing of these native species is difficult. Thus, D. longicaudata was chosen due to its specificity for the family Tephritidae and its ease of laboratory rearing. In this paper we review the literature on Brazilian fruit fly biological control and suggest that those tactics can be used on a large scale, together creating a biological barrier to the introduction of new fruit fly populations, reducing the source of outbreaks and the risk of species spread, while decreasing the use of insecticides on fruit destined for domestic and foreign markets.

Anastrepha species (Diptera: Tephritidae), their hosts and parasitoids in southern Amapá State, Brazil

This work was carried out to record the species of Anastrepha, their host plants and associated parasitoids in Laranjal do Jari and Vitória do Jari, Amapá State. Fleshy fruits of 17 species of 13 families were sampled, from February to July of 2006, in main districts of both municipalities. Nine species of Anastrepha and six species of braconid parasitoids were sampled during this study.

Diversity of Anastrepha spp. (Diptera: Tephritidae) and associated braconid parasitoids from native and exotic hosts in southeastern Bahia, Brazil

We documented fruit fly-host associations and infestation rates over 5 yr in the state of Bahia, Brazil, by systematically collecting native and introduced fruits in backyard and commercial orchards, experimental stations, and patches of native vegetation. Fruit were collected in multiple sites in the southern and southernmost regions of Bahia. A total of 942.22 kg from 27 fruit species in 15 plant families was collected throughout this study. Of these, 15 plant species from six families were infested by Anastrepha species. A total of 11,614 fruit flies was reared from the fruit (5,178 females and 6,436 males). No specimens of Ceratitis capitata (Wiedemann) were recovered. Eleven Anastrepha species were recovered from the collected fruit: Anastrepha antunesi Lima (0.04%), Anastrepha distincta Greene (0.1%), Anastrepha fraterculus (Wiedemann) (53.5%), Anastrepha leptozona Hendel (4.5%), Anastrepha manihoti Lima (0.1%), Anastrepha montei Lima (1.0%), Anastrepha obliqua (Macquart) (33.0%), Anastrepha pickeli Lima (2.0%), Anastrepha serpentina (Wiedemann) (1.0%), Anastrepha sororcula Zucchi (3.0%), and Anastrepha zenildae Zucchi (1.8%). We recovered 1,265 parasitoids (Hymenoptera: Braconidae) from Anastrepha pupae. Three species of braconids were found to parasitize larvae of nine Anastrepha species. The most common parasitoid species recovered was Doryctobracon areolatus (Szépligeti) (81.7%), followed by Utetes anastrephae (Viereck) (12.2%) and Asobara anastrephae (Muesebeck) (6.1%). We report A. fraterculus infesting Malay apple Syzygium malaccense (L.) Merr. & L. M. Perry and A. fraterculus, A. sororcula, and A. zenildae infesting araza Eugenia stipitata McVaugh for the first time in Brazil.

EFEITO DO NIM (AZADIRACHTA INDICA) NA MOSCA-DAS-FRUTAS CERATITI. CAPITATA (DIPTERA: TEPHRITIDAE) E SEU PARASITOIDE DIACHASMIMORPHA LONGICAUDATA (HYMENOPTERA: BRACONIDAE)

RESUMO Este trabalho teve como objetivo avaliar a ação do inseticida botânico nim em larvas de Ceratitis capitata, bem como no parasitismo destas larvas por Diachasmimorpha longicaudata. Para tanto, larvas de 3o ínstar de C. capitata foram mergulhadas por 30 segundos em soluções contendo as concentrações de 0,5%, 1% e 1,5% de um produto comercial à base de óleo de nim a 0,37% (3.686 ppm), além da testemunha mergulhada apenas em água destilada. Em seguida, as larvas foram expostas ao parasitismo de D. longicaudata por um período de 2 horas e 30 minutos. No experimento sem chance de escolha, para cada tratamento, uma única “unidade de parasitismo” foi pendurada no interior da gaiola. No experimento com livre escolha, as “unidades de parasitismo” foram penduradas no interior de uma mesma gaiola, de forma que os parasitoides tivessem livre acesso a todos os tratamentos. No experimento sem livre escolha, foi constatado que o aumento da concentração de nim diminuiu a atração das fêmeas, o número de fêmeas que efetuaram postura, o índice de parasitismo e a emergência dos parasitoides. No experimento com livre escolha, verificou-se que a emergência dos parasitoides e o índice de parasitismo também foram prejudicados nas maiores concentrações de nim. A ação isolada do nim, quando em contato com as larvas de 3o instar, não afetou a emergência de C. capitata.

Parasitoid diversity (Hymenoptera: Braconidae and Figitidae) on frugivorous larvae (Diptera: Tephritidae and Lonchaeidae) at Adolpho Ducke Forest Reserve, Central Amazon Region, Manaus, Brazil

This study aimed to identify parasitoid species of frugivorous larvae and to describe the tritrophic interactions involving wild fruits, frugivorous insects and their natural enemies at Adolpho Ducke Forest Reserve (RFAD) (Manaus, AM, Brazil). Collections were performed in four 1 km² quadrants in the corners of the RFAD. The wild fruits were collected inside the forest in access trails leading to each collection area and in trails that surrounded the quadrants, up to five metres from the trail on each side. The fruits were placed in plastic containers covered with thin fabric, with a vermiculite layer on the base to allow the emergence of flies or parasitoids. Seven Braconidae species were collected, distributed among Opiinae: Doryctobracon areolatus (Szépligeti, 1911), Utetes anastrephae (Viereck, 1913), and Opius sp., and Alysiinae: Asobara anastrephae (Muesebeck, 1958), Phaenocarpa pericarpa Wharton and Carrejo, 1999, Idiasta delicata Papp, 1969, and Asobara sp. Parasitism rates by braconids and figitids are presented. Doryctobracon areolatus was the most frequent, parasitizing the highest number of fly species, and showing the highest parasitism percentage in larvae feeding on Micropholis williamii fruits. The collected figitids belong to Aganaspis nordlanderi Wharton, 1998 and A. pelleranoi (Brethes, 1924). All 15 tritrophic associations are new records for the Brazilian Amazon region. The RFAD is an important natural reservoir of frugivorous larvae parasitoids.