ABSTRACT Knowledge about the spatial distribution of fruit flies (Diptera: Tephritidae) and tritrophic interactions (fruit-fruit fly parasitoid) contributes to the monitoring and maintenance of the numerical density at a level lower than economic damage. The purpose of this study was to identify the spatial distribution and associations of fruit flies with their parasitoids and host plants in the municipality of Bom Jesus-PI. The flies were obtained from fruit collection from July 2018 to May 2019. A total of 1,711 individuals were obtained, represented by six species: Anastrepha obliqua (Macquart, 1835), An. fraterculus (Wiedemann, 1830), An. alveata Stone, 1942, An. sororcula Zucchi, 1979, An. zenildae Zucchi, 1979 and Ceratitis capitata (Wiedemann, 1824). Anastrepha obliqua was the species with the widest distribution throughout the ecotone area. Ceratitis capitata is distributed only in the urban perimeter. A tritrophic relationship occurred between four species of parasitoids, Asobara anastrephae (Muesebeck, 1958) or Opius sp. associated with An. obliqua in Spondias mombin or S. tuberosa fruits. Opius sp. has also been associated with An. alveata in Ximenia americana. Pachycrepoideus vindemiae was obtained from C. capitata in Malpighia emarginata, in addition to An. obliqua in Averrhoa carambola. Therefore, fruit flies are associated with native fruit trees (S. tuberosa, S. mombin, S. purpurea, P. acutangulum, Inga laurina, X. americana) and exotic fruits (M. emarginata, A. carambola, P. guajava). Ceratitis capitata was recorded for the first time in the state of Piauí infesting I. laurina (Sw.) Willd. This is the first record of the parasitoid genus Spalangia. in An. obliqua in Piauí and in the semiarid region of Brazil.

ABSTRACT 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 wild-guava fruits, M. tomentosa.

RESUMO: Registra-se a ocorrência de Neosilba zadolicha McAlpine & Steyskal pela primeira vez em frutos de mandacaru (Cereus jamacaru DC.), no município de Alvorada do Gurgueia, centro-sul do estado do Piauí (8º22’35.63” S, 43º51’25,96” W). Foram obtidos 11 exemplares de frutos de mandacaru, em área de mata nativa, de fevereiro de 2016 a maio de 2016. Este é o primeiro registro de N. zadolicha em uma espécie de Cactaceae.

ABSTRACT: For the first time, the presence of Neosilba zadolicha McAlpine & Steyskal is being recorded in mandacaru fruits [Cereus jamacaru DC.], in the municipality of Alvorada do Gurgueia, in the south-central region of the State of Piauí, Brazil (8º22’35.63” S, 43º51’25,96” W). Eleven specimens were obtained from mandacaru fruits in an area of native forest between February and May of 2016. This is the first record of N. zadolicha in a Cactaceae species.

Resumo: O objetivo deste trabalho foi determinar os parâmetros biológicos e as exigências térmicas de Trichogramma pretiosum linhagem TM sobre ovos de Helicoverpa armigera. Para cada fêmea, foi oferecida uma cartela contendo 20 ovos de H. armigera, às temperaturas de 18, 20, 22, 25, 28, 30 e 32°C. Todos os estádios de vida de T. pretiosum foram observados sob as dadas condições de temperatura. A temperatura ótima para o parasitismo de T. pretiosum foi de 25°C e a maior longevidade foi verificada à mesma temperatura. As maiores taxas de emergência do parasitoide foram às temperaturas de 22, 25 e 28°C. A maior proporção de indivíduos de T. pretiosum emergidos por ovo foi observada a 18°C. Quanto à razão sexual, a maior proporção de fêmeas ocorreu a 28°C, e o maior percentual de viabilidade do parasitismo foi observado à mesma temperatura. O limiar térmico inferior para o desenvolvimento pré-imaginal total e as exigências térmicas de T. pretiosum foram de 10,82°C e 134,55 grau-dias, respectivamente. O número estimado de gerações de T. pretiosum às temperaturas médias do Município de Bom Jesus, Piauí, foi de 4 por mês.

Abstract: The objective of this work was to determine the biological parameters and thermal requirements of Trichogramma pretiosum TM strain reared on Helicoverpa armigera eggs. A card containing 20 eggs of H. armigera was offered for each T. pretiosum female, at temperatures of 18, 20, 22, 25, 28, 30 and 32°C. All life stages of T. pretiosum were observed under the given temperature conditions. The optimum temperature for the parasitism of T. pretiosum was 25°C, and the highest longevity was found at the same temperature. The highest parasitoid emergence rates occurred at temperatures of 22, 25 and 28°C. The highest proportion of T. pretiosum individuals emerged per egg was observed at 18°C. Concerning the sex ratio, the highest proportion of females occurred at 28°C, and the highest percentage of parasitism viability was observed at this same temperature. The lowest thermal threshold for total preimaginal development and thermal requirements of T. pretiosum were 10.82°C and 134.55 degree-days, respectively. The estimated number of generations of T. pretiosum in the average temperatures of municipality of Bom Jesus, state of Piauí, Brazil is four per month.

Atualmente centenas de plantas são investigadas para se conhecer os princípios ativos responsáveis pela atividade inseticida contra as diversas pragas de importância econômica. Com o objetivo de verificar a atividade inseticida das cascas do caule de Croton urucurana Baillon 1864 (Euphorbiaceae) em relação a Anagasta kuehniella Zeller 1879 (Lepidoptera: Pyralidae), avaliou-se o extrato metanólico (EMeOH), fração diclorometano (FDM), a fração acetato de etila (FAE) e a resina in natura, os quais foram adicionados à dieta artificial. O EMeOH (0,5, 1,0 e 20,%) e a resina in natura (2,0%), não interferiram no peso, sobrevivência das larvas de 4ª ínstar, bem como nos demais parâmetros analisados. A fração FDM (2,0%) causou mortalidade de 65%, e a dieta artificial contendo 2,0, 1,0, e 0,5% de FAE causou 100, 55 e 68% de mortalidade respectivamente quando comparado com o controle, constatando-se as menores eficiências de conversão do alimento para a FDM (2,0%) e FAE (1,0%). Através do ensaio tríptico realizado com o fluido do intestino médio das larvas, foi possível verificar que a atividade tríptica e quimiotríptica para as larvas alimentadas com dieta artificial contendo o EMeOH e a resina in natura não apresentaram diferenças significativas.

Hundreds of plant species have been studied in order to find out the active ingredient responsible for their insecticidal activity against the pests of economic importance. To verify the insecticidal activity in the husk of stem of Croton urucurana Baillon 1864 (Euphorbiaceae) against Anagasta kuehniella Zeller 1879 (Lepidoptera: Pyralidae), the methanolic (EMeOH) extract, dichloromethane fraction (FDM), ethyl acetate fraction (FAE) and crude resin, incorporated into an artificial diet were evaluated. EMeOH (0.5, 1.0 and 2.0%) and crude resin (2.0%) interfered with neither the weight nor the survival of fourth instar larvae and other analyzed parameters. FDM (2.0%) fraction caused mortality of 65%, and the artificial diet containing 2.0, 1.0 and 0.5% FAE caused 100, 55 and 68% mortality respectively when compared with the control, confirming the least efficiency rates of food conversion for FDM(2.0%) and FAE(1.0%). The tryptic analysis performed with the midgut fluid of fourth-instar larvae demonstrated that tryptic and chymiotryptic activities for the larvae fed artificial diet containing EMeOH and crude resin were not different.