Unlike endothermic animals, insectivorous bats are known to choose unique life history traits due to energy availability. They must deposit a fat to compensate their energy demands throughout the period of hibernation during late autumn, and especially female bats demand maximum energy during pregnancy and lactating periods.
Nevertheless, most studies on the energy strategy of bats focused on the reproduction or pre-hibernation period and hibernation. Therefore, we investigated the annual energy strategies of the insectivorous Eastern Bent-winged bats by measuring monthly nutrient intake and fat accumulation. We tested the hypothesis that insectivorous bats select optimal energy strategy in accordance with life history traits.
We measured that annual changes in daily intake and body weight of the Eastern Bent-winged bat (Miniopterus fuliginosus) population, and tested the correlation between daily diet intake and body weight of the bat.
Results/Conclusions
The body weight of bats was lowest in March then then increased form April until July, when the reproduction period ended, in accordance with the increased food intake, and then reached second lowest in September just before pre-hibernation. Surprisingly, throughout the pre-hibernation period bats achieved a substantial body weight reaching to the yearly peak in November, although the amount of daily food intake decreased from August to October.
Our findings strongly support that the bat has evolved the flexible energy strategies by employing optimal foraging behavior and the suitable physiological condition for reproduction and hibernation.