Abstract

VILLAMIZAR-RAMIREZ, Ángela M; SERRANO-CARDOZO, Víctor H  and  RAMIREZ-PINILLA, Martha P. Reproductive activity of a population of Nephelomys meridensis (Rodentia: Cricetidae) in Colombia. Mastozool. neotrop. [online]. 2017, vol.24, n.1, pp.177-189. ISSN 0327-9383.

We studied the annual reproductive activity of a population of Nephelomys meridensis in an Andean oak forest in the Cordillera Oriental of Colombia. Monthly during a year, Sherman live traps were established in 5 fixed stations (20 traps per station) during 4 nights per month, along an altitudinal range of 2530-2657 m. Reproductive condition was established in adult females by external morphology including nipple development, abdomen distension, and features of the vaginal opening. Adult females were categorized as pregnant or in lactation. Additionally, female reproductive condition was complemented with the analysis of vaginal smears of each female with open vagina and with a general description of the estrous cycle for some females in captivity. Females of this population of N. meridensis reproduce continuously throughout the year, and females were pregnant, in lactation or in estrous several months. The presence of postpartum estrus both in captivity and in the field was observed. Under captivity conditions, the estrous cycle can last more than 5 days because some phases were extended more than 2 days. No relationship was found between the frequency of reproductive females in each reproductive state and the monthly average of rainfall or with the variation in the environmental availability of food (arthropod abundance and oak fructification). Therefore, in this popula­tion of N. meridensis females have an aseasonal polyestric pattern suggesting a constant offer of environmental resources for reproduction.

Keywords : Andean forest; Environmental factors; Nephelomys meridensis; Reproduction.