Ovariole structure and oogenesis in queens and workers of the stingless bee Melipona quadrifasciata (Hymenoptera: Apidae, Meliponini) kept under different social conditionsStructure des ovarioles et ovogenèse chez les reines et les ouvrières de l’abeille sans aiguillon, Melipona quadrifasciata (Hymenoptera, Apidae, Meliponini) en fonction des conditions socialesOogenese und Ovariolenstruktur bei Königinnen und Arbeiterinnen der Stachellosen Biene Melipona quadrifasciata (Hymenoptera: Apidae, Meliponini), die unter unterschiedlichen sozialen Bedingungen gehalten wurden

The high variability in the reproductive biology of stingless bees makes them very amenable for comparative studies with other eusocial bee taxa. We investigated the structural organization of the ovaries of Melipona quadrifasciata queens and workers kept under different social conditions by analyzing their general histology, mitotic activity, and microfilament organization. The overall dynamics of ovarian activity were similar in the two castes, and at emergence their ovarioles contained a previtellogenic follicle. Stingless bees and honey bees differ in the structural organization in the lower germarium, but they have in common synchronized mitotic activity and putative germ line stem cells in the terminal filament. Unlike honey bees, stingless bee workers lay trophic eggs in addition to reproductive eggs. The overall similarities in oogenesis between the two taxa suggest that the decision to form trophic eggs should only occur in the late stages of oogenesis.