Reproductive phenologies of phyllostomid bats in the Central Amazon

Abstract

Mammals tend to align their most energetically demanding phenological events with periods of peak resource availability. Their reproductive phenology is influenced by local resource availability, potentially leading to geographical variation in their breeding strategy. Although the Amazon is the world’s epicenter of bat diversity, the reproductive phenology of Amazonian bats remains poorly known. Seasonality induces fluctuations in resource availability and most phyllostomid species, crucial agents of seed dispersal, pollination and arthropod suppression in the Neotropics, have been described to exhibit seasonal bimodal polyestry. However, current understanding of phyllostomid reproductive phenology is impaired by the paucity of comparative examinations of the phenologies of sympatric species, using consistent classification schemes based on the number and timing of annual peaks in pregnancy and lactation. Using a multi-year dataset from Central Amazonia, we examined the reproductive phenology of nine bat species (Artibeus concolor, A. obscurus, A. lituratus, Carollia brevicauda, C. perspicillata, Gardnerycteris crenulatum, Lophostoma silvicolum, Rhinophylla pumilio, and Trachops cirrhosus), as well as two feeding ensembles (i.e., frugivores and gleaning animalivores). Only three of the nine species exhibited a bimodal reproductive phenology. Six species and the frugivore ensemble showed unimodal reproductive phenology, while gleaning animalivores displayed an amodal pregnancy pattern. All species except L. silvicolum had their primary pregnancy peak during the mid-dry season. A reproductive peak during the early wet season, or local variation in the duration of the fruiting season may explain the deviation of our observations from the expected bimodal polyestry.