Seasonal changes in 3D space use and foraging strategies in the avivorous bat Ia io

To cope with seasonal changes in food availability, animals need to optimize their behaviors, including shifts in temporal activity patterns and spatial use in habitats. Most studies focused on the temporal activity pattern or habitat use in two-dimensional (2D) space. However, studies on the simultaneous changes in temporal activity patterns and habitat use in three-dimensional (3D) space are limited. In this study, we used the great evening bat (Ia io) to investigate differences in the activity pattern and space use during the summer and autumn. We collected and analyzed the Global Positioning System (GPS) data and activity data obtained from accelerometers. The results showed that bats displayed seasonal variations in their movement patterns. Specifically, compared with summer, I. io individuals were found to extend their foraging duration and adopt a low-energy consumption pattern of activity in autumn. Furthermore, there was a notable increase in the vertical extent of the 3D habitat utilization range for these bats, although the 2D habitat size in autumn remained similar to that in summer. These changes manifested both temporally and spatially, potentially as a response to the reduced availability of insect resources from summer to autumn, and the arrival of migratory birds in autumn as an alternative food source. Our results suggest that I. io seasonally adjust their foraging strategies and spatial use from two to three dimensions. Our study provides important insights into the seasonal behaviour dynamics of bats during summer and autumn, which may contribute to understanding their ecological strategies and inform conservation efforts.