Ovarian cycle of southern brown howler monkey (Alouatta guariba clamitans) through fecal progestin measurement

Abstract

The ovarian cycle in howler monkeys (genus Alouatta) has beean investigated through several biological parameters (ranging between 16.3 and 29.5 days); however, no data exist concerning the ovarian activity of the southern brown howler monkey (Alouatta guariba clamitans). This study aimed to describe the ovarian cycle of A. g. clamitans by profiling fecal progestin concentrations. Over 20 weeks, fecal samples of eight captive adult females of A. g. clamitans were collected. The collections were made at dawn, 5 days a week, and the samples were frozen immediately following collection. Next, they were dried, pulverized and hormonal metabolites were extracted to determine progestin concentrations by enzyme immunoassay. Of the 758 samples tested, the mean concentration of fecal progestins was 2866.40 ± 470.03 ng/g of dry feces, while the mean concentration at baseline was 814.47 ± 164.36 ng/g of dry feces. Among the eight females, one showed no ovarian cyclicity and three presented periods of probable absence of cyclicity and low progestin concentrations. A mean duration of 16 ± 0.52 days was observed for the 35 cycles studied. The interluteal phase lasted 4 ± 0.37 days on average, with a mean concentration of fecal progestins of 467.98 ± 29.12 ng/g of dry feces, while the luteal phase lasted 11 ± 0.50 days, with a mean concentration of 4283.27 ± 193.31 ng/g of dry feces. Besides describing the characteristics of the ovarian cycle, possible causes for the low concentrations of fecal progestins and periods of absence of cyclicity are also discussed.

Reproductive physiology with emphasis on endometrial cycles of woolly and uakari monkeys—A literature review

“…Kaiser (1947) evaluated the uterus of the mantled howler ( Alouatta paliatta ) and did not observe spiral or analogous arteries in the endometrium. Contrary, other studies report the presence of erythrocytes in the vaginal lumen at the end of the luteal phase, suggesting that this species has a menstrual cycle (Kugelmeier et al, 2011; Silvestre et al, 2017). Similar features were reported in the Geoffroy's spider monkey ( Ateles geoffroyi ), spiral arteries were also absent in the endometrium and there was mild bleeding with a small number of erythrocytes in the vaginal lumen, suggesting micromenstruation (Hernández‐López et al, 1998).…”

“…However, the maintenance of wild species in captivity can produce important reproductive variations due to multiple factors, such as stress, availability of resources, territories, and the composition of social groups (Mayor et al, 2017). Previous research has described different presentations of the sexual cycle depending on the primate species; while the menstrual cycle has been identified in Alouatta guariba clamitans (Silvestre et al, 2017) and genera Aotus , Cebus and Sapajus (de Lima Cardoso et al, 2021; Mayor et al, 2019), Callithrix (Abbott, 1992) and Saimiri (Srivastava et al, 1970) have estrous cycles. However, reproductive knowledge is still absent for many medium‐ and large‐sized primates, such as woolly monkeys (genus Lagothrix ) and uakaris (genus Cacajao ).…”

Assessing female reproductive status of spectral tarsier (Tarsius tarsier) using fecal steroid hormone metabolite analysis

“…Nowadays, a large number of studies have demonstrated the reliability of quantifying fecal sex hormone metabolites for assessing female reproductive physiology, in a large number of primate species (e.g. Fürtbauer, Schülke, Heistermann, & Ostner, ; Heistermann et al, ; Scheun et al, ; Silvestre et al, ). This helped to provide important information on basic reproductive characteristics (e.g.…”