Ovariole structure and oogenesis in queens and workers of the stingless bee Melipona quadrifasciata (Hymenoptera: Apidae, Meliponini) kept under different social conditionsÉrica Donato Tanaka1, Weyder Cristiano Santana1 and Klaus Hartfelder2
1 Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Brazil
2 Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brazil
Received 4 June 2008 – Revised 5 November 2008 – Accepted 19 November 2008 - Published online 3 February 2009
Abstract - 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.
Key words: worker reproduction / follicle development / actin cytoskeleton / ovary histology
© INRA, DIB-AGIB, EDP Sciences 2009