NITROGEN AND ENERGY-REQUIREMENTS OF THE SHORT-TAILED FRUIT BAT (CAROLLIA-PERSPICILLATA) - FRUIT BATS ARE NOT NITROGEN CONSTRAINED

Nitrogen (N) and energy (E) requirements were measured in adult Caroll ia perspicillata which were fed on four experimental diets. Bats ate 1 .3-1.8 times their body mass . day(-1) and ingested 1339.5-1941.4 kJ . kg(-0.75) . day(-1). Despite a rapid transit time, dry matter digesti bility and metabolizable E coefficient were high (83.3% and 82.4%, res pectively), but true N digestibility was low (67.0%). Mass change was not correlated with E intake, indicating that bats adjusted their meta bolic rate to maintain constant mass. Bats were able to maintain const ant mass with digestible E intake as low as 1168.7 kJ . kg(-0.75) . da y(-1) or 58.6 kJ .. Metabolic fecal N and endogenous urinary N losses were 0.87 mg N . g(-1) dry matter intake and 172.5 mg N . kg(-0.75) . day(-1), respectively, and bats required 442 mg N . kg(-0.75) . day(-1 ) (total nitrogen) or 292.8 mg N . kg(-0.75) . day(-1) (truly digestib le nitrogen) for N balance. Based on E and N requirements and digestib ilities, it was calculated that non-reproductive fruit bats were able to meet their N requirements without resorting to folivory and without over-ingesting energy. It was demonstrated that low metabolic fecal r equirements allowed bats to survive on low-N diets.