Abstract
The energy budget, water balance and osmoregulation of the fruit bat, Rousettus aegyptiacus, were studied during normal hydration and during water restriction (oven-dried apple diet). The water input and output were balanced during both normal hydration and water restriction. The kidney of the fruit bat is well adapted to handle the water load from its fruit diet by excreting large volumes (14% of the body mass per day) of dilute urine (113±25 mosmol·kg H2P-1) as well as reducing urine volume (-95%) and increasing urine osmotic concentration (555±280 mosmol·kg H2O-1) during water restriction. The haematocrit, plasma haemoglobin and total protein concentrations did not increase during water restriction and heat exposure, suggesting the conservation of plasma volume. Gross energy intake was not alfected by water restriction. However, digested energy intake and digestibility were significantly reduced. The effective regulation of energy and water budgets during water restriction suggests that the fruit bat can cope with seasonal climatic changes and with variable fruit supply during various seasons.
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Abbreviations
- BM:
-
body mass
- DEI:
-
digested energy intake
- EWL:
-
evaporative water loss
- GEL:
-
gross energy intake
- NH:
-
normal hydration
- T a :
-
ambient temperature
- WR:
-
water restriction
References
Arad Z, Horowitz M, Eylath U, Marder J (1989) Osmoregulation and body fluid compartmentalization in dehydrated heatexposed pigeons. Am J Physiol 257:R377-R382
Arevalo F, Perez-Suarez G, Lopez-Luna P (1987) Hematological data and hemoglobin components in bats (Vespertilionidae). Comp Biochem Physiol 88A:447–450
Baker MA (1984) Cardiovascular and respiratory responses to heat in dehydrated dogs. Am J Physiol 246:R369-R374
Bassett JE (1980) Control of postprandial water loss in Myotis lucifugus. Comp Biochem Physiol 65A:497–500
Bergmans W (1978) Review of drinking behavior of African fruit bats (Mammalia: Megachiroptera). Bull Carnegie Mus Nat Hist 6:20–25
Borut A, Horowitz M, Castel M (1972) Blood volume regulation in the spiny mouse: capillary permeability changes due to dehydration. Symp Zool Soc Lond 31:175–189
Brosh A, Shkolnik A, Choshniak I (1986) Metabolic effects of infrequent drinking and low-quality feed on Bedouin goats. Ecology 67:1086–1090
Calder WA III, Hiebert SM (1983) Nectar feeding, diuresis, and electrolyte replacement of hummingbirds. Physiol Zool 42:325–334
Carpenter RE (1969) Structure and function of the kidney and water balance of desert bats. Physiol Zool 42:288–302
Degen AA (1977) Responses to dehydration in native fat-tailed awassi and imported German Mutton Merino sheep. Physiol Zool 50:284–293
Geluso KN (1980) Renal form and function in bats: an ecophysiological appraisal. In: Wilson DE, Gardner AL (eds) Proceedings Fifth International Bat Research Conference. Tech Press, Lubbock, TX, USA, pp 403–414
Guggenheim K, Kaufman NA, Reshef U (1985) Food composition and tables for use. The Ministry of Education, Jerusalem
Hewitt S, Wheldrake JF, Baudinette RV (1981) Water balance and renal function in the Australian desert rodent Notomys alexis: the effect of diet on water turnover rate, glomerular filtration rate, renal plasma flow and renal blood flow. Comp Biochem Physiol 68A:405–410
Horowitz M, Samueloff S (1979) Plasma water shifts during thermal dehydration. J Appl Physiol 47:738–744
Jürgens KD, Bartels H, Bartels R (1981) Blood oxygen transport and organ weights of small bats and small non-flying mammals. Respir Physiol 45:243–260
Keegan DJ (1977) Aspects of the assimilation of sugars by Rousettus aegyptiacus. Comp Biochem Physiol 58A:349–352
Korine C, Arad Z (1993) Effect of water restriction on temperature regulation of the fruit-bat Rousettus aegyptiacus. J Therm Biol 18:61–69
Kulzer E (1979) Ecology and geographical range in the fruit-eating cave bat genus Rousettus Gray 1821 — A review. Bonn Zool Beitr 30:233–275
Maloiy GMO (1973) Water metabolism of East African ruminants in arid and semi-arid regions. Z Tierzucht Züchtungsbiol 90:219–228
Morrison DW (1980) Efficiency of food utilization by fruit-bats. Oecologia 45:270–273
Nagy KA, Shoemaker VH, Costa WR (1976) Water, electrolyte, and nitrogen budgets of jackrabbits (Lepus californicus) in the Mojave desert Physiol Zool 49:351–363
Noll UG (1979) Body temperature, oxygen consumption, noradrenaline response and cardiovascular adaptations in the flying fox, Rousettus aegyptiacus. Comp Biochem Physiol 63A:79–88
Pfeiffer EW, Reinking LN, Hamilton JD (1979) Some effects of food and water deprivation on metabolism in black-tailed prairie dogs, Cynomys ludovicianus. Comp Biochem Physiol 63A:19–22
Reaka ML, Armitage KB (1976) The water economy of harvest mice from xeric and mesic environments. Physiol Zool 49:307–327
Reese JB, Haines H (1978) Effects of dehydration on metabolic rate and fluid distribution in the jackrabbit, Lepus californicus. Physiol Zool 51:155–165
Roberts JR, Hughes MP (1983) Glomerular filtration rate and drinking rate in Japanese quail, Coturnix coturnix japonica, in response to acclimation to saline water. Can J Zool 61:2394–2398
Rübsamen K, Engelhardt W von (1975) Water metabolism in the llama. Comp Biochem Physiol 52A:595–598
Ryan KL, Proppe W (1990) Effects of compartmental fluid repletion on heat-induced limb vasodilation in dehydrated baboons. Am J Physiol 259:R1139-R1147
Schmidt-Nielsen K (1964) Desert animals. University Press, Oxford, UK
Stalling DT, Haines H (1982) Effect of dehydration on water-turnover rates and hematocrits in the rice rat, Oryzomys palustris. Comp Biochem Physiol 72A:301–306
Storf R (1978) Untersuchungen über den Wasserhaushalt von Rousettus aegyptiacus. (quoted in Kulzer, 1979)
Studier EH, Wilson DE (1983) Natural urine concentrations and composition in neotropical bats. Comp Biochem Physiol 75A:509–515
Thomas DW (1984) Fruit intake and energy budgets of frugivorous bats. Physiol Zool 57:457–467
Thomas SP, Follette DB, Farabaugh T (1990) Influence of air temperature on ventilation rates and thermoregulation of a flying bat. Am J Physiol 60:R960-R968
Westhuyzen J van der (1988) Heamatology and iron status of the Egyptian fruit-bat, Rousettus aegyptiacus. Comp Biochem Physiol 90A:117–120
Willems NJ, Armitage KB (1975) Thermoregulation and water requirements in semiarid and montane populations of the least chipmunk, Eutamias minimus — II. Water balance. Comp Biochem Physiol 52A:109–120
Zervanos SM, McCort WD, Graves HB (1983) Salt and water balance of feral versus domestic Hampshire hogs. Physiol Zool 56:67–77
Zurovsky Y, Shkolnik A, Ovadia M (1984) Conservation of blood plasma fluids in hamadryas baboons after thermal dehydration. J Appl Physiol 57:768–771
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Arad, Z., Korine, C. Effect of water restriction on energy and water balance and osmoregulation of the fruit bat Rousettus aegyptiacus . J Comp Physiol B 163, 401–405 (1993). https://doi.org/10.1007/BF00265645
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DOI: https://doi.org/10.1007/BF00265645