2004/11/19 by Bradley Hartman Bakken, Todd J. McWhorter, Ella Tsahar +1 · 2 citations
Environmental Science · Agricultural and Biological Sciences · #Physiological and biochemical adaptations #Animal Behavior and Reproduction #Bat Biology and Ecology Studies #Morning #Evening #Reabsorption #Allometry #Biology #Renal function #Animal science #Diel vertical migration #Zoology #Endocrinology #Kidney #Ecology #Botany
paper · doi:10.1242/jeb.01238
openalex publication_date 2004/11/19 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/01
Small nectarivorous vertebrates face a quandary. When feeding, they must eliminate prodigious quantities of water; however, when they are not feeding, they are susceptible to dehydration. We examined the role of the kidney in the resolution of this osmoregulatory dilemma. Broad-tailed hummingbirds (Selasphorus platycercus) displayed diurnal variation in glomerular filtration rate (GFR). During the morning, midday and evening, GFRs were 0.9+/-0.6, 1.8+/-0.4 and 2.3+/-0.5 ml h(-1), respectively. At midday, GFR increased linearly with increased water intake. During the evening, hummingbirds decreased renal fractional water reabsorption linearly with increased water intake. Broad-tailed hummingbirds appeared to cease GFR at night (-0.1+/-0.2 ml h(-1)) and decreased GFR in response to short-term ( approximately 1.5 h) water deprivation. GFR seems to be very responsive to water deprivation in hummingbirds. Although hummingbirds and other nectarivorous birds can consume astounding amounts of water, a phylogenetically explicit allometric analysis revealed that their diurnal GFRs are not different from the expectation based on body mass.