Data from: Resource availability and roosting ecology shape reproductive phenology of rainforest insectivorous bats

Bats in temperate and subtropical regions typically synchronize birth of a single young with peaks in resource availability driven by local climate patterns. In tropical rainforests, insects are available throughout the year, which might allow departures from seasonal monoestry, although reproductive energy budgets may be constrained by the cost of commuting to foraging grounds from distant roosts. To test these hypotheses, we simultaneously tracked female reproductive activity of 11 insectivorous bat species, insect biomass, and local weather variables for 20 months in a Malaysian rainforest. Five species roost in forest structures and hence have low commuting costs, and six species depend on caves, which are limited in the landscape, and are presumed to incur higher commuting costs to the forest foraging ground. Monthly insect biomass was positively correlated with monthly rainfall, and there was a significant relationship between insect biomass and lactation in cave-roosting, but not forest-roosting species. Cave-roosting species were seasonally monoestrus, with parturition confined to a two-month period, whereas in forest-roosting species, pregnancy and lactation were recorded throughout the year. Our results suggest that the energetic costs of commuting from roosts to foraging grounds shape annual reproductive patterns in tropical rainforest insectivorous bats. Ongoing changes in forest landscapes are likely to increase these costs for cave-roosting bats, further restricting reproductive opportunities. Climate change is projected to influence the timing of rainfall events in many tropical habitats, and this may disrupt relationships between rainfall, insect biomass and bat reproductive timing, further compromising reproductive success.