Reproductive Stages and Ovarian Histophysiology in Artibeus planirostris (Chiroptera: Phyllostomidae) in the Dry and Rainy Months in a Municipality of the Mesoregion of the Mata Pernambucana, Northeastern Brazil

Abstract

In this study, reproductive stages and ovarian histophysiology were investigated in adult female Artibeus planirostris in the municipality of Vitória de Santo Antão, Pernambuco, Northeastern Brazil. They were captured over one night each month (November 2016 to November 2017). Based on the monthly average precipitation, the dry (September to February) and rainy (March to August) months were grouped. Through external body morphology, females were classified as inactive, pregnant, lactating, and post-lactating. Only the inactive (n = 13) were euthanized for morphophysiological analyzes. Blood samples were obtained for estrogen measurement and, after euthanasia, the ovaries were collected and processed by routine histological techniques. In morphometry, were considered: the area of the ovary, the presence, and the area of the ovarian follicles (unilaminar and multilaminar primary, antral, and Graafian), as well as the quantification of the corpus luteum. In immunohistochemistry, PCNA (Proliferating cell nuclear antigen) was used. The results showed pregnant females only in dry months, however inactive, lactating, and post-lactating females were collected in dry and rainy months. Estrogen levels and the presence of positive PCNA cells were higher in the rainy months. The Graafian follicle occurred only in these months, whereas the corpus luteum was found in all specimens from the dry months. Although A. planirostris has a tendency to start gestation in dry months and mating from mid to the end of the rainy months, this species showed adaptability influenced by environmental variations throughout the reproductive cycle, indicating a aseasonal polyestry.