Ovary Activation in Virgin Queens of Plebeia lucii Moure (Hymenoptera: Meliponini)

Stingless bees (Meliponini) are commonly used in meliponiculture and pollination. In colonies of Plebeia lucii Moure (Hymenoptera: Meliponini), a single queen undergoes changes in hormone profiles, as well as physiological, behavioral, transcriptional, and morphological modifications, particularly after copulation. Among these changes, some bee species exhibit ovary activation in virgin queens before mating. However, few studies have described the reproductive system of virgin queens of Meliponini. The colony’s dynamics depend on the queen, making an understanding of its reproductive biology essential for effective management of this species. This study aimed to determine whether ovary activation occurs before mating in virgin queens of P. lucii. Three virgin queens of P. lucii were collected from royal chambers of different colonies, and their ovaries were analyzed using light microscopy. Each virgin queen possessed two ovaries, each composed of four meroistic polytrophic ovarioles containing a terminal filament, a germarium, and a vitellarium. Oocytes in early developmental stages, spherical in shape and with well-developed nurse cells, were observed in these ovarioles, along with nurse and oocytic chambers in the vitellarium. Additionally, vitellogenesis was observed in the vitellarium, characterized by the formation of elliptical oocytes, yolk accumulation, and the degeneration of adjacent nurse cells. These findings indicate that ovary activation occurs before mating in virgin queens of P. lucii.