Testicular morphometry and morphology in insectivorous bat (Molossus molossus Pallas, 1776) (Chiroptera, Molossidae) / Morfologia e morfometria testicular em morcego insetívoro (Molossus molossus Pallas, 1776) (Chiroptera, Molossidae)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Testicular morphometric analysis have been implemented in order to infer on the gonadal dynamics and reproductive capacity of the insectivorous bat Molossus molossus in the southeast of Minas Gerais, Brazil, collected during the four annual climatic seasons, from 2007 to 2008. After euthanasia animal tissues were collected and included in methacrylate, and histological preparations were evaluated in light microscopy. The ratio between the elements that constitute the testicular parenchyma was obtained using the software Image Pro Plus. So various gonadal parameters were calculated. The percentage of testicular parenchyma occupied by seminiferous tubules was significantly higher in fall and winter for the summer, reflecting directly on the percentage occupied by intertubular compartment, which in turn was higher in the summer for the fall and winter. The tubulosomatic index was lower in summer, as well as the percentage of the tubular compartment occupied by lumen and tunica propria, and the tubular diameter, which was lower in this station for the fall and winter and highest in the fall for the spring. The percentage of testes represented by the intertubular compartment was higher in the summer, as the percentage occupied by Leydig cells (LC) for fall and winter. The percentage of LC represented by the nucleus was greater in winter, while the percentage of cytoplasm was lower in this season. There was greater volume cytoplasmatic and of LC from the spring, with higher values in the fall. Analysis of correlation between the testicular morphometry and abiotic environmental factors confirmed the influence of climatic factors on the reproduction of males M. molossus. The increase of various tubular morphometric parameters observed in the fall, as well as the diameter of the seminiferous tubules, indicating increased of spermatogenic activity in this season. The greater investment in intertubular tissue and LC in the summer and the increase in cytoplasmatic and total of LC volume in the fall indicate greater androgenic capacity in those seasons. Although elongated spermatids were present in the testicular lumen, as well as spermatozoa in the epididymis throughout the year, we concluded that male M. molossus presents reproductive seasonality with high spermatogenic capacity in the fall and peaks of androgenic capacity in the summer and fall, tubular length far above the average of all mammals already studied, one of the largest proportions of seminiferous tubules, and testicular pattern characteristic of most mammals.

ASSUNTO(S)

morcego testis reproduction spermatogenesis bat sazonalidade seasonality testículo reprodução espermatogênese biologia geral

ACESSO AO ARTIGO

Documentos Relacionados