Spondias mombin as a reservoir of fruit fly parasitoid populations in the Eastern Amazon: an undervalued ecosystem service

The Amazon and Its Biodiversity: a Source of Unexplored Potential Natural Enemies for Biological Control (Predators and Parasitoids)

The Amazon is an important source of natural enemies for biological control. The diversity of biocontrol agents in the Amazon is considerably higher than that in other Brazilian regions. However, few studies have focused on the bioprospecting of natural enemies in the Amazon. Furthermore, the expansion of agricultural land in recent decades has caused biodiversity loss in the region, including the loss of potential biocontrol agents, due to the replacement of native forests with cultivated areas and forest degradation. In this study, we reviewed the main groups of natural enemies in the Brazilian Legal Amazon: predatory mites (mainly Acari: Phytoseiidae), ladybirds (Coleoptera: Coccinellidae), and social wasps (Hymenoptera: Vespidae: Polistinae) and the Hymenoptera parasitoids of eggs (Trichogrammatidae) and of frugivorous larvae (Braconidae and Figitidae). The main species prospected and used in biological control are presented. The lack of knowledge and perspectives regarding these groups of natural enemies as well as the challenges of conducting research in the Amazon is discussed.

Irradiation and parasitism affect the ability of larval hemocytes of Anastrepha obliqua for phagocytosis and the production of reactive oxygen species

The development of the parasitoid Doryctobracon crawfordi (Viereck) (Hymenoptera: Braconidae) in Anastrepha obliqua (McQuart) (Diptera: Tephritidae) larvae is unviable in nature; however, if the host larva is irradiated at 160 Gy, the parasitoid develops and emerges successfully. This suggests that radiation affects the immune responses of A. obliqua larvae, while the underlying mechanisms remain to be revealed. Using optical and electronic microscopies we determined the number and type of hemocyte populations found inside the A. obliqua larvae, either nonirradiated, irradiated at 160 Gy, parasitized by D. crawfordi, or irradiated and parasitized. Based on flow cytometry, the capacity to produce reactive oxygen species (ROS) was determined by the 123-dihydrorhodamine method in those hemocyte cells. Five cell populations were found in the hemolymph of A. obliqua larvae, two of which (granulocytes and plasmatocytes) can phagocytize and produce ROS. A reduction in the number of cells, mainly of the phagocytic type, was observed, as well as the capacity of these cells to produce ROS, when A. obliqua larvae were irradiated. Both radiation and parasitization decreased the ROS production, and when A. obliqua larvae were irradiated followed by parasitization by D. crawfordi, the reduction of the ROS level was even greater. In contrast, a slight increase in the size of these cells was observed in the hemolymph of the parasitized larvae compared to those in nonparasitized larvae. These results suggest that radiation significantly affects the phagocytic cells of A. obliqua and thus permits the development of the parasitoid D. crawfordi.