Reproductive Biology of Bats in the Colombian Tropical Dry Forest

ABSTRACT The Tropical Dry Forest (TDF) of central Colombia is a highly seasonal and vulnerable ecosystem where bats play a key role in ecosystem functioning through seed dispersal and arthropod regulation. However, reproductive strategies of Neotropical bats in seasonal environments remain poorly documented. This study evaluated reproductive seasonality and dietary patterns of 31 bat species across seven TDF fragments, assessing how bimodal rainfall regimes and associated food pulses influence reproductive timing. Reproductive condition was determined using external morphology, vaginal cytology in females, and testicular histology in males. Diet composition was assessed through fecal analysis, identifying 21 plant genera and 67 insect taxa. Monthly reproductive activity was analyzed in relation to precipitation patterns and food availability. Most species exhibited a bimodal polyestrous reproductive pattern, representing the first documented evidence of this cycle for 12 species in Colombia, including Artibeus planirostris and Myotis nigricans . Pregnancy peaks occurred mainly during dry seasons, whereas parturition and lactation coincided with the onset of rainy periods, when fruit and insect availability increased. Vaginal cytology identified five estrous phases—proestrus, estrus, metestrus, diestrus, and anestrus—and proved more accurate than external morphology for detecting reproductive activity, particularly in females classified as inactive based on external traits. Reproductive activity was strongly associated with rainfall‐driven resource availability, while temperature showed no significant effect. These findings indicate that bat reproduction in Tropical Dry Forests is tightly synchronized with seasonal fluctuations in food resources mediated by precipitation. Our results highlight the conservation value of forest fragments as providers of continuous resources and suggest that climate‐driven alterations in rainfall regimes may pose significant risks to bat population stability in Neotropical dry forests.