DANIEL, S; KORINE, C; PINSHOW, B; Jacob Blaustein Inst. Desert Res. and Ben-Gurion University of the Negev; Jacob Blaustein Inst. Desert Res. ; Jacob Blaustein Inst. Desert Res. and Ben-Gurion University of the Negev: Roost selection, thermoregulatory behavior and foraging activity in a desert dwelling bat during lactation
We investigated the patterns of energy use by lactating female Hemprich�s long-eared bats (Otonycteris hemprichii). These bats roost in crevices, forage on terrestrial arthropods while flying, and are active in the research area from March to October. We used radio telemetry and microdataloggers to estimate time budgets, find roosts and measure roost (Tr) and skin temperatures of 7 free-ranging lactating animals in the Negev highlands. The bats were captured by mist netting while they foraged, or near their roosts. Body mass, nipple condition and abdominal palpation allowed us to approximate body condition and reproductive status of the bats. We evaluated roost preference with regard to Tr and distance to their main foraging and drinking site, and the use of torpor and passive rewarming and changes in foraging time in relation to energy use. Bats lactated from mid June until the beginning of August. We found two concentrations of roosts, one 2 and one 8 km from the bats� main foraging and drinking site. Most of the bats roosted in the closer concentration. Roost exit times, foraging bout length (10-209 min) and bout frequency (2-6 per night) changed daily and among individuals with no correlation with sunset time. However, foraging time (y) increased significantly as lactation progressed (x = number of days from parturition) (y = – 0.2537x2 + 11.577x + 167.31, R2 = 0.47, P < 0.005, n = 22) and bats exited roosts earlier. Bats selected warm roosts (Tr > 27 �C) that may allow fast growth of the young, and used shallow torpor and passive rewarming to save energy.
