Evidence for adaptation of Rhagoletis pomonella (Diptera: Tephritidae) on large-thorn hawthorn, Crataegus macracantha, in Okanogan County, Washington State, USA.

The apple maggot fly, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae), was introduced from eastern North America into western North America via infested apples (Malus domestica Borkhausen) about 44 yr ago, where it subsequently adapted to 2 hawthorn species, Crataegus douglasii Lindley and C. monogyna Jacquin. Here, we test whether R. pomonella has also adapted to large-thorn hawthorn, Crataegus macracantha Loddiges ex Loudon, in Okanogan County, Washington State, USA. In 2020, 2021, and 2022, fruit of C. macracantha were shown to ripen in late September and were infested at rates from 0.7% to 3.0%. In laboratory rearing studies, large-thorn hawthorn flies from C. macracantha eclosed on average 9-19 days later than apple flies from earlier ripening apple (August-early September), consistent with large-thorn hawthorn flies having adapted to the later fruiting phenology of its host. In a laboratory no-choice test, significantly fewer (64.8%) large-thorn hawthorn than apple flies visited apples. In choice tests, greater percentages of large-thorn hawthorn than apple flies resided on and oviposited into C. macracantha versus apple fruit. Large-thorn hawthorn flies were also smaller in size than apple flies. Our results provide further support for the recursive adaptation hypothesis that R. pomonella has rapidly and independently specialized phenologically and behaviorally to different novel hawthorn hosts since its introduction into the Pacific Northwest of the USA, potentially leading to host race formation.

Occurrence of fruit flies (Diptera: Tephritidae) in the municipality of Alvorada do Gurguéia in South Central Piauí, Brazil

The state of Piauí is in a Cerrado/Caatinga transition area, which is known the richness of its fauna and flora. Therefore, this work aims to know the diversity of fruit fly species in cashew orchards and native forest fragments in the south-central region of Piauí. Fruit flies were collected in McPhail traps and by sampling fruits. The material collected from the traps and the fruits in the two areas were taken to the Laboratory of Phytotechnics from Campus Prof. Cinobelina Elvas at the Universidade Federal do Piauí (UFPI/CPCE), municipality of Bom Jesus, Piauí, Brazil. In McPhail traps, six species of the genus Anastrepha: A. alveata, A. dissimilis, A. fraterculus, A. manihoti, A. obliqua, and A. zenildae were captured, of which A. fraterculus, A. obliqua, and A. zenildae were present in both areas. Anastrepha alveata, A. dissimilis and A. manihoti occurred only in the cashew orchard. In fruit sampling, A. fraterculus, A. obliqua, and A. zenildae infested wild-guava fruits, Myrcia tomentosa (Myrtaceae), in native forest. Anastrepha fraterculus, A. obliqua and A. zenildae were obtained directly from M. tomentosa fruits and from traps. The availability of host fruits is the factor that most influences the population fluctuation of fruit flies, mainly in the native forest area. Anastrepha manihoti is reported for the first time in the state of Piauí. This is the first record of A. fraterculus, A. obliqua and A. zenildae, infesting wildguava fruits, M. tomentosa.

A Minor Role of Host Fruit on the Parasitic Performance of Aganaspis daci (Hymenoptera: Figitidae) on Medfly Larvae.

Host fruit is known to strongly affect the performance of both fruit pests and their potential natural enemies. This is particularly important in the control of tephritid fruit flies, whose larvae develop inside the fruit and thus create a set of foraging problems for parasitoids. In the present study, we assessed the response of female Aganaspis daci (Weld) (Hymenoptera: Figitidae), one of the most promising parasitoids for tephritid biocontrol in the Mediterranean Basin, to different potential host fruit species. We measured the olfactory response to medfly-infested and uninfested fruits, and several biological parameters of A. daci when different infested fruits were offered under both laboratory and greenhouse conditions. Our results showed that this parasitoid was significantly more attracted to apples and uninfested fruit. Moreover, parasitic activity was similar among the tested fruits under both conditions, showing very high values in the laboratory and a much poorer performance when conditions were variable. This suggests that A. daci may be a good candidate to be included in mass releases against the medfly regardless of the affected crop, but only when climate conditions are not expected to hinder its normal activity.

Response of Male Queensland Fruit Fly (Diptera: Tephritidae) to Host Fruit Odors.

The surveillance and management of Dacini fruit fly pests are commonly split by fly gender: male trapping focuses on the dacine 'male-lures', whereas female trapping focuses on lures based on host-fruit volatiles. Although the males of several Dacini species have been reported to be attracted to host fruit volatiles, the option of using host-fruit traps for males has, to date, been ignored. Males of the cue-lure responsive fruit fly Bactrocera tryoni (Froggatt) have been recorded as responding to host-fruit volatile blends, but it is not known how frequently this happens, if it is age-dependent, or the strength of the response relative to cue-lure throughout the year. Here, we conducted an olfactometer experiment to test the lifetime (weeks 1-15) response of B. tryoni males to the odor of tomato, a known host of this fly, and compare catches of wild males to tomato-based traps and cue-lure traps in the field. Bactrocera tryoni males started to respond to tomato odor as they sexually matured (2 to 3 wk olds) and thereafter showed consistent olfactory response until advanced age (15 wk). In the field, wild males were captured by tomato-based traps throughout the year at a level not significantly different from cue-lure traps. The reason for the consistent B. tryoni male response to host fruit odor at this stage is not known, but it certainly occurs at a level greater than can be continued to be ignored for both basic and applied research.

Diachasmimorpha longicaudata Parasitism Response to Medfly Host Fruit and Fruit Infestation Age.

The parasitoid Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) is increasingly being used in integrated pest management (IPM) programs as a biological control agent in order to suppress tephritid fruit flies of economic importance. Innate and acquired behavioral responses-such as pest host fruit preference-of parasitoids can modulate their efficiency in the field and should be taken into consideration prior to parasitoid species' selection for mass-rearing. We have assessed the influence of medfly-infested (two infestation ages, 1 and 4-d-old) and uninfested fruit species on host preference and efficiency of D. longicaudata by using a multistep assay including olfactory, laboratory and semi-field trials. We found that D. longicaudata was significantly more attracted to medfly-infested apples for both infestation ages, with the oldest being the most preferred. D. longicaudata exhibited a significant preference among the four fruits tested. The implications of these behavioral responses of D. longicaudata to medfly host fruits and infestation age are discussed in relationship to its use in IPM programs in the Mediterranean basin area.

Hosts and parasitoids of fruit flies (Diptera: Tephritoidea) in the State of Tocantins, Brazil

Fruit flies were obtained from 13 species of naturally infested fruits in the central region of Tocantins State, from January to October 2005. A total of 1,753 female flies were collected that belong to 11 species: Anastrepha coronilli Carrejo & González, A. fraterculus (Wied.), A. mucronota Stone, A. obliqua (Macquart), A. sororcula Zucchi, A. striata Schiner, A. turpiniae Stone, A. zenildae Zucchi, Anastrepha sp., Ceratitis capitata (Wied.) and Neosilba sp. Also six species of parasitoids were associated to Anastrepha larvae: Asobara anastrephae (Muesebeck), Doryctobracon areolatus (Szépligeti), Doryctobracon sp., Opius bellus Gahan, Opius sp. and Utetes anastrephae (Viereck).

Moscas-das-frutas foram obtidas de larvas criadas em frutos de 13 espécies de frutíferas, naturalmente infestadas, de janeiro a outubro de 2005. Coletaram-se 1.753 fêmeas de 11 espécies: Anastrepha coronilli Carrejo & González, A. fraterculus (Wied.), A. mucronota Stone, A. obliqua (Macquart), A. sororcula Zucchi, A. striata Schiner, A. turpiniae Stone, A. zenildae Zucchi, Anastrepha sp., Ceratitis capitata (Wied.) e Neosilba sp. Foram coletadas também seis espécies de parasitóides associados às larvas de Anastrepha: Asobara anastrephae (Muesebeck), Doryctobracon areolatus (Szépligeti), Doryctobracon sp., Opius bellus Gahan, Opius sp. e Utetes anastrephae (Viereck).