Emergence and pupal mortality factors of Anastrepha obliqua (Macq.) (Diptera: Tephritidae) along the fruiting season of the host Spondias dulcis L.

Abstract

The emergence and pupal mortality factors of Anastrepha obliqua (Macq.) (Diptera: Tephritidae) along the fruiting season of the host plant, Spondias dulcis L. (Anarcadiaceae), were studied in Sertãozinho, SP, Brazil, under field and laboratory conditions. Eclosed and uneclosed puparia were recorded in two experimental conditions. The number of emerged flies and parasitoids were determined in the eclosed puparia. The uneclosed puparia were inspected and classified into living (dormant) and dead. The following pupal mortality factors were considered: disease, desiccation, predation and parasitism. Out of the total of 1,204 puparia analyzed, 53% emerged and 47% remained uneclosed. Out of the uneclosed puparia, 25.3% contained dormant pupae and 21.7% showed no signs of emergence. Among the dormant pupae, 17.8% were flies, 0.2% of which emerged; 7.5% were parasitoids, 4.7% of them emerged. The initial parasitism was 8.6%, increasing to 15.3% after the emergence of dormant pupae. Predatory activity (natural condition), especially when time of exposure was long, and desiccation (laboratory condition) were the predominant causes of pupal mortality. Variation in mortality caused by parasites and pathogens (bacteria and fungi) seems to play a minor role. Control by predators on fruit fly population is significant. However, the factors, which regulate induction, maintenance and termination of dormancy, are still to be determined. An estimate of the dormancy and of the biotic and abiotic pupal mortality factors are essential to understand the adaptive strategies of A. obliqua and its parasitoids and to develop effective methods of control in tropical regions.