Showing papers by "Gustavo Ferreira Martins published in 2004"

A comparative study of the ovaries in some Brazilian bees (Hymenoptera; Apoidea)

Abstract: A morfologia do ovario em 33 especies de abelhas apresentando diferentes graus de sociabilidade foi estudada. Todas as especies apresentaram ovario do tipo meroistico politrofico formado por um germario anterior e um vitelario basal. No germario estao localizadas as celulas germinativas e o vitelario apresenta foliculos arranjados linearmente. Cada foliculo e constituido pela câmara nutridora e pela câmara ovocitica, ambas revestidas por uma camada unica de celulas foliculares. O numero de ovariolos/ovario e de ovocitos maduros/ovario, o comprimento dos ovariolos, o tamanho e a largura dos ovocitos, a altura do epitelio folicular e a distância intertegular foram analisadas, mostrando que os representantes das tribos altamente eussociais Meliponini e Apini tem os maiores ovarios, enquanto as abelhas solitarias apresentam maiores ovocitos. Os resultados obtidos sugerem que ha uma tendencia para o aumento no tamanho do ovario e numero de ovariolos conforme ha um aumento no nivel de sociabilidade das abelhas.

Changes in the reproductive tract of Melipona quadrifasciata anthidioides (Hymenoptera: Apidae, Meliponini) queen after mating

Abstract: The effect of mating on the morphological features of the female reproductive system of the stingless bee Melipona quadrifasciata anthidioides was investigated as well as the amount of time required for spermatozoa transfer to the spermatheca after mating. Five-day old queens were allowed to mate in the presence of one male. After abandoning the females, the male was analyzed to verify genitalia loss. Fifteen mated queens were obtained and three specimens were dissected in the following periods after mating: 5, 10, 15, 20 and 40 days. For each mated queen analyzed there was another virgin queen used as control. Reproductive systems were extracted with light and scanning electron microscope procedures. Results indicated that mating induced ovarian activity and the increase of the spermatheca wall height. Ovarian activity was asynchronic, but in physogastric queens there was synchronism in oocyte production. Ovarioles in virgin queens were stretched, but after mating an enlargement of the basal portion occurred. Follicle degeneration was frequent and seemed to follow virgin queen aging. Ten minutes after mating we found spermatozoa in the spermatheca. Three hours was the necessary for spermatheca lumen to become filled with spermatozoa.