Fruit flies (Diptera: Tephritidae) and their parasitoids associated with acerola, mango, and guava in the municipality of Brasil Novo, Pará

Submitted on September 21 , 2020 and accepted on February 17 , 2021. 1 Instituto Nacional de Pesquisas da Amazônia, Programa de Pós Graduação em Agricultura no Trópico Úmido, Manaus, Amazonas, Brazil. souzaasd31@gmail.com 2 Universidade Federal do Pará (UFP A), campus de Altamira, Altamira, Pará, Brazil. jwilsonps@gmail.com 3 Instituto Nacional de Pesquisas da Amazônia, Coordenação de Capacitação, Manaus, Amazonas, Brazil. ronchi@inpa.gov .br Corresponding author: souzaasd31@gmail.com Fruit flies (Diptera: Tephritidae) and their parasitoids associated with acerola, mango, and guava in the municipality of Brasil Novo, Pará


INTRODUCTION
Fruit flies (Diptera: Tephritidae) are considered insect pests of great importance in world fruit production, causing significant economic losses in production and/ or leading to increased costs and management practices of orchards . The economic losses caused by fruit fly infestation reach approximately US $ 1 billion per year worldwide and US$ 242 million per year in Brazil (Oliveira et al., 2013).
Damage is caused to the fruits by the females at egg laying and by the larvae feeding on the fruit pulp , and losses can reach 100% in some untreated orchards depending on the cultivated species (Hernandes et al., 2013).
The economically important species of Tephritidae in Brazil are separated into four genera: Anastrepha Schiner, 1968;Rhagoletis Loew, 1862;Ceratitis MacLeay, 1829; and Bactrocera Macquart, 1835. The last two are represented by a single species each, the Mediterranean fruit fly, Ceratitis capitata (Wiedemann, 1824), and the carambola fruit fly, Bactrocera carambolae (Drew & Hancock, 1994). The genus Anastrepha is to date represented by 121 species identified throughout the Brazilian territory and infest several native and/or exotic fruits (Zucchi & Moraes, 2008).
Knowledge about the diversity of fruit flies, host plants, and infestation rates is fundamental to define management practices for this insect pest . However, according to Zucchi & Moraes (2008), only 51% of fruit flies recorded in Brazil have at least one known host.
Of the 28 Anastrepha species recorded in the state of Pará, only 11 have at least one known host plant . Twenty-two host plant species were described Rev. Ceres, Viçosa, v. 68, n.6, p. 579-585, nov/dec, 2021 in association with Anastrepha species, in addition to C. capitata which is associated with four plant species Araújo et al., 2016).
Therefore, our objectives were study the tritrophic relationship between species of Anastrepha, their parasitoids, and the three commercial fruits acerola (Malpighia emarginata DC.), mango (Mangifera indica L.), and guava (Psidium guajava L.) in the municipality of Brasil Novo, state of Pará, and to determine the infestation rates and percentage of parasitism.
Freshly fallen fruits from acerola, mango, and guava trees, which were not in an advanced stage of decay, hollow inside and/or half-eaten by birds and other animals, were collected weekly. The sample size varied according to fruit availability in the field, as recommended by Silva et al. (2011).
After collection, the fruits were packed in trays or plastic bags and taken to the Agricultural Entomology Laboratory (LEA) at the Federal University of Pará -UFPA, campus Altamira -PA. In the laboratory, the fruits were counted, separated, and weighed. The fruits were placed in plastic containers with the bottom covered with a layer of sterilized and moistened sand, covered with voile fabric, tightened with an elastic band or a holed lid, and kept in a protected and ventilated area.
The fruit samples were examined every five days to keep moisture and remove the puparium. The puparium were placed in a new container with a thin layer of moistened sand, covered with voile fabric tightened with an elastic band or a holed lid, and monitored daily for emergence of fruit flies and/or their parasitoids. After emergence, the insects were kept alive for 48 hours, so that their morphological structures acquired a peculiar color, which is important for taxonomic identification. Then, the insects were sorted by sex, counted, and stored in 70% alcohol until species identification, as recommended de Silva et al. (2011).
The insects were identified at the Agriculture Insect Rearing Laboratory of the National Research Institute of the Amazon (INPA). The adult females collected from the fruits were analyzed according to the wing and thoracic patterns and morphometric measurements of the aculeus apex, according to the dichotomous keys by Zucchi (2000) and Zucchi et al. (2011).
The parasitoids of the Braconidae family were identified based on the shape of the mandible and the clypeus, structure and color of the wing and the propodeum (Marinho et al., 2011). The individuals of the Figitidae family were analyzed based on the characteristics of the antenna, thorax, and anterior wing venation (Guimarães & Zucchi, 2011). The individuals of the Pteromalidae family were identified based on the legs, wings and antennae (Wharton & Yoder, 2019). The voucher specimens of fruit flies and parasitoids sampled were deposited in the Biological Scientific Collections at INPA.
The parameters evaluated were the indices of infestation per kilogram of fruit, pupal viability (PV), parasitism rate (PT), and frequency of parasitoids per species (F). Calculations were made according to Sá et al. (2008)

RESULTS AND DISCUSSION
A total of 4,103 fruits of acerola, mango, and guava were collected, corresponding to 122.3 kg, from which 7,650 puparium of fruit flies were obtained, the majority from samples of guava with 4,324 puparium, followed by mango with 2,682 puparium, and acerola with 644 puparium.
Two species of fruit flies were identified infesting the fruits sampled: 1,339 individuals of Anastrepha obliqua (Macquart, 1835) and 438 individuals of Anastrepha striata Schiner, 1868. A. obliqua infested the samples of all fruit species, with frequencies of 90.3% in mangoes, 7.7% in acerolas and 2.1% in guavas, while A. striata infested guavas and acerolas, with frequencies of 98.8% and 1.2%, respectively.
The species A. striata is an important native agricultural pest that occurs in the Amazon region and has guava as its main host (Jesus-Barros et al., 2012). This is the first record of A. striata infesting acerola fruits in the state of Pará, and there is only one record of infestation of this fruit in the Amazon region, in Ilha de Santana, AP, by Almeida et al. (2016).
The species A. obliqua is predominant in the Amazon region, since the species has a polyphagous feeding habit and infest several host plants (Zucchi & Moraes, 2008). However, it preferentially attacks plants in the family Anacardiaceae (Ferreira et al., 2003). In the Amazon region, this species is described as infesting 33 species of host plants belonging to eight botanical families -Anacardiaceae, Apocynaceae, Chrysobalanaceae, Combretaceae, Malpighiaceae, Myrtaceae, Oxalidaceae and Sapotaceae. .
The average fruit-fly infestation rates in the guava samples were 3.3 puparium/fruit and 110.8 puparium/kg ( Table 1). The average infestation rate/kg was higher than those reported by other studies such as the survey carried out by Santos et al. (2012), in which they found infestation of 99.3 puparium/kg in collections carried out in organic guava crops in the municipality of Maceió, Alagoas. Similarly, Moura & Moura (2011) found infestation levels lower than the findings of the present study, reporting 30.3 puparium/kg in samples collected in a guava orchard in Fortaleza, Ceará.
The average pupal viability (PV) in the guava samples was 63.2% (Table 1). This result is lower than the PV found by Dias et al. (2013) in a survey carried out in municipalities along the border area of Rio Grande do Sul, Argentina and Uruguay, where, in guava fruits, the PV of A. fraterculus was 76% and C. capitata was 85%. However, the result of this study was higher than that reported by Santos et al. (2012) for organic guava crops in the municipality of Maceió, Alagoas, where they found VP of 59.6%.
In this study, the PV found for guava fruits was higher than the other fruits. According to Sá et al. (2008), a high pupal viability is not desirable in pest management, because hosts that allow good larval performance contribute to the maintenance and increase of the fruit fly population; therefore, as it is a potential host for fruit fly, the guava crop should have special attention.
The average rates of infestation by fruit flies in the mango samples were 4.8 puparium/fruit and 34.9 puparium/kg (Table 2). These rates were higher than the reports of Sousa et al. (2019) for mango of Tommy Atkins variety, with infestation rates of 4.1 puparium/kg. However, they were lower than the infestation rates Raga et al. (2011) found in a survey carried out in 67 municipalities in the state of São Paulo, 59 puparium/ fruit and 283.3 puparium/kg. Acerola fruits showed the lowest infestation per fruit, with mean of 0.3 puparium/fruit, which is probably due to their smaller size (Table 3). Leite et al. (2017) report infestation rate of 0.04 puparium/fruit in Nossa Senhora do Livramento, BA, while Araújo et al. (2011) describe infestation rates of 0.01 to 0.91 puparium/fruit in Mossoró, RN.
The average PV obtained in the present study in the acerola samples was 21.8% (Table 3), which was close to that observed by Lemos et al. (2017)  The lowest PV was recorded in the samples of acerola, which may indicate a low preference for this fruit by the Anastrepha species compared with the other fruits studied in this work. Another reason that may have influenced VP and If is the high level of parasitism in relation to other fruit.
Of the 599 parasitoids that emerged in the collected samples, 292 were found in guavas, 205 in mangoes, and 102 in acerolas. The species associated with A. striata in guava were the family Figitidae (Aganaspis pelleranoi (Brèthes, 1924)); the family Braconidae (Doryctobracon areolatus (Szépligeti, 1911), Odontosema albinerve   , 1909, Opius bellus (Gahan, 1930, Utetes anastrephae (Viereck, 1913)); and the family Pteromalidae (Pachycrepoideus vindemmiae (Rondani, 1875)) ( Table  4). The results found in this study agree with those of Jesus- Barros et al. (2012), who found that these species were associated with A. striata in surveys carried out in five municipalities in the state of Amapá and surveys carried out by Dutra et al. (2013) in the state of Amazonas. The parasitoid species A. pelleranoi, D. areolatus, O. albinerve, O. bellus, and U. anastrephae associated with A. obliqua were found in mango fruits. The two species of parasitoids D. areolatus and U. anastrephae associated with A. obliqua were recorded in acerola fruits (Table 4). These species were also found associated with A. obliqua in the survey carried out by Marsaro Júnior et al. (2011) in the state of Roraima and by Sousa et al. (2016) in three municipalities in the state of Amapá.
The average parasitism rate in guava samples was 8% ( Table 5). The results were close to those found by Leal et al. (2009), who recorded levels of parasitism from 1.5 to 11.5% in surveys carried out in four municipalities in the state of Rio de Janeiro. Further, the results of the present study were higher than that reported by Bittencourt et al. (2012) for surveys in garden orchards in the Southcoast of Bahia, in which the authors observed parasitism rate of 1.61 in guava samples.
The average parasitism rate in mango fruits was 4.8% (Table 6), the lowest in relation to the other fruits studied, a result close to that found by Marinho et al. (2009). The factors that can initially interfere in parasitism are the volatiles of infested fruits (Eitam et al., 2003), the removal of fruits from the field to the laboratory, but a characteristic that can directly affect the parasitism index is the morphology of the fruit because in smaller fruits with shallow pulp the indexes are higher in relation to large fruits (Hickel, 2002).
The average parasitism rate in acerola was 15.1% (Table  7), which was higher than the rates recorded in the other fruit species sampled, probably due to the small size of the fruit. According to Nascimento et al. (2015), parasitism is influenced by the physical characteristics of the fruit, with the highest rates occurring in small-sized fruits as in the case of Spondias mombin L.
In general, parasitism rates are low, but varies according to location and host species in the area (Carvalho et al., 2010), therefore, the selection of plant hosts with high rates of parasitism should be considered for planting in fruit growing areas, aiming to increase natural parasitism of fruit flies .   Among the parasitoids observed, D. areolatus presented the highest frequency in all the fruits studied, varying between 57.4 to 60.8%, followed by A. pelleranoi, varying from 18.1 to 58.4%, and U. anastrephae, varying from 3.5 to 16.2% (Table 8). Several surveys conducted in Brazil showed that D. areolatus is the most frequent species in collections of fruit flies, which is due to the size of its ovipositor and egg-laying performance at different stages from immature eggs to third-instar larvae (Marinho et al., 2011;Nunes et al., 2011).
Guava was the most susceptible crop to fruit fly infestation among the three fruit species studied. This is the first record of A. striata infesting acerola (Malpighia emarginata) fruits in the state of Pará and   Doryctobracon areolatus was the most frequent parasitoid species in all samples of the fruits collected, providing important information for the management of fruit flies.