Climate sensitivity effects on tropical bat ecology

Tropical ecosystems are highly sensitive to climatic variation, yet biological responses to climate fluctuations often emerge after substantial temporal lags. Insectivorous bats are useful sentinels of climatic dynamics due to their high metabolic demands and reliance on weather-sensitive insect prey. We quantified the extent to which weather variation correlated with the short-term behavioral and long-term foraging responses of a large wrinkle-lipped free-tailed bat (Mops plicatus) colony in Thailand. As response variables, we used a nine-year dataset (2013-2021) of daily bat evening emergence times and a 22-year dataset (1998-2019) of monthly guano yields. As predictor variables, we used ERA5-Land reanalysis estimates of temperature and precipitation extracted from concentric ring buffers (0-10, 10-20, and 20-30 km) surrounding the bat colony. Sliding-window analysis showed that bat evening emergence time tracked sub-seasonal weather variation at lags of a few days to about three months. Preceding temperature and precipitation were associated with shifts in bat evening emergence timing. Monthly guano yield declined with elevated temperatures at lags of up to three months. Guano yield showed a sustained long-term decline of 56.62% over two decades (seasonal Mann-Kendall Z = -11.585, p < 0.001). Behavioral response alone appeared insufficient to offset the decline in guano yield, which suggests that alternative factors influence guano production, including declines in prey availability, bat abundance, or foraging time. Our results show that increasing temperatures correlated with seasonally contrasting shifts in bat evening emergence time (later in April-May, earlier in September-October) and reduced guano production up to three months after warming periods occurred.