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Ovarian characterization and definition of the number of generations of south american fruit flies during the crop cycle in two orchards in the region of Porto Alegre, State of Rio Grande do Sul, Brasil

The South American fruit fly, Anastrepha fraterculus (Wiedemann, 1830) (Diptera: Tephritidae) is a major pest of fruit trees in southern Brazil. This study aimed to characterize the populations of fruit flies captured in traps with food baits, through the characterization of reproductive organs of females compared with females of the laboratory strain. Collections were performed in two orchards; the first, peach trees with conventional management; the second, guava trees without management; during a crop cycle. McPhail traps were used with grape juice at 25% and hydrolyzed protein at 5%. Collected females were dissected; their ovaries were measured in width and length, and the degree of sexual maturation was determined. Females maintained in the laboratory, with age controlled, were also dissected to serve as a comparison to the field specimens. A total of 895 females of A. fraterculus were captured in the orchard of guava and 139 in peach trees. Three physiological stages of the females from the ovarian cell differentiation were determined: immature, in development and mature. Ovaries from mature laboratory females were significantly smaller than those from the field. In the peach orchard, through the peaks of immature flies, three generations were identified during the crop cycle, until the harvest. In guava, the population peak of immature flies occurred at the end of the cycle, indicating that the population was able to colonize other fruit.

Anastrepha; ovary; reproduction


Instituto Biológico Av. Conselheiro Rodrigues Alves, 1252 - Vila Mariana - São Paulo - SP, 04014-002 - São Paulo - SP - Brazil
E-mail: arquivos@biologico.sp.gov.br