Evaporative water loss, nitrogen excretion and osmoregulation in phyllomedusine frogs

1975 ◽  
Vol 100 (4) ◽  
pp. 331-345 ◽  
Author(s):  
Vaughan H. Shoemaker ◽  
Lon L. McClanahan
Keyword(s):  
Water Loss ◽  
Evaporative Water Loss ◽  
Nitrogen Excretion ◽  
Evaporative Water

Water loss and nitrogen excretion in sharp-nosed reed frogs (Hyperolius nasutus: anura, Hyperoliidae)

1982 ◽  
Vol 97 (1) ◽  
pp. 335-343
Author(s):  
P. C. Withers ◽  
S. S. Hillman ◽  
R. C. Drewes ◽  
O. M. Sokol
Keyword(s):  
Surface Area ◽  
Water Loss ◽  
High Surface ◽  
Waste Product ◽  
Volume Ratio ◽  
Evaporative Water Loss ◽  
Nitrogen Excretion ◽  
Mucous Gland ◽  
Specific Rate ◽  
Evaporative Water

Sharp-nosed African reed frogs, Hyperolius nasutus Gunther, are small (0.4 g) hyperoliids which have minimal rates of evaporative water loss (4.5 mg g-1 h-1; 0.3 mg cm-2 h-1) that are only 1/10 to 1/20 that of a typical frog, Hylaregilla, of comparable size (171 mg g-1 h-1, 4.8 mg cm-2 h-1). The surface-area-specific resistance to water flux of H. nasutus dorsal skin (96–257 sec cm-1) is similar to that of other ‘waterproof’ frogs (300–400), of cocooned frogs (40–500), and of desert reptiles (200–1400). However, H. nasutus can greatly increase the rate of evaporative water loss during radiative heat stress by mucous gland discharge, and by exposing the ventral skin. Urea is the principal nitrogenous waste product of H. nasutus and uric acid comprises less than 1% of the total nitrogen excretion for both H. nasutus and H. regilla. Other ‘waterproof’ frogs, in contrast, are uricotelic. Lethal dehydration requires less than two weeks in H. nasutus, despite its low surface-area-specific rate of water loss, because of its small size and concomitantly high surface-to-volume ratio. The rate of urea accumulation during dehydration was 23 mM g-1 day-1, which is sufficiently low that urea accumulation would not be lethal before the frog had succumbed to dehydrational death. Consequently, there appears to be little or no selective advantage for uricotely in small ‘waterproof’ frogs, such as H. nasutus.

Shell Resistance and Evaporative Water Loss from Bird Eggs: Effects of Wind Speed and Egg Size

1981 ◽  
Vol 54 (2) ◽  
pp. 195-202 ◽  
Author(s):  
James R. Spotila ◽  
Christina J. Weinheimer ◽  
Charles V. Paganelli
Keyword(s):  
Wind Speed ◽  
Water Loss ◽  
Egg Size ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Bird Eggs

Scaling of Evaporative Water Loss in Marsupials

1986 ◽  
Vol 59 (1) ◽  
pp. 1-9 ◽  
Author(s):  
David S. Hinds ◽  
Richard E. MacMillen
Keyword(s):  
Water Loss ◽  
Evaporative Water Loss ◽  
Evaporative Water
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