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Old Before Their Time? Aging Rate In Flies Twice As Fast In Wild Than In Laboratory

Date:
September 6, 2008
Source:
University of Chicago Press Journals
Summary:
Conventional wisdom suggests that stress accelerates aging -- but is it really true? Evolutionary studies of aging use short-lived animals under laboratory conditions -- constant temperature and humidity, no parasites, superabundant food. Researchers identified individual stilt-legged flies in their harsh natural environments while simultaneously monitoring their cousins in the lab. In males, the rate of aging was as least two times greater in the wild. For both sexes, life in the wild was dramatically shorter. More study of how environment affects gene expression is needed.
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Evolutionary studies of aging typically utilize small, short-lived animals (insects, worms, mice) under benign conditions – constant temperature and humidity, no parasites, superabundant food – in the laboratory.

Oddly enough, very little is known about aging in such animals in their harsh, stressful natural environments. Could it be that these laboratory "guinea pigs" actually age much more slowly in captive luxury than do their wild cousins?

Nori Kawasaki, Rob Brooks, and Russell Bonduriansky of the University of New South Wales, and Chad Brassil of the University of Nebraska, set out to find out, using the giant Australian stilt-legged fly Telostylinus angusticollis, a beautiful, sexually dimorphic animal that breeds on rotten wood. To identify individual flies in the wild, they wrote codes (combinations of Arabic numerals and Latin and Japanese letters) on the flies' backs using enamel paint, and recorded the comings and goings of marked individuals on Acacia trunks while simultaneously monitoring their captive cousins in the lab.

Analysis, published in the September issue of the American Naturalist, revealed striking contrasts between wild and captivity: in males, the rate of aging (measured as the rate of increase of mortality rate with age) was as least two-fold greater in the wild than in the laboratory. Curiously, wild females did not seem to age at all. For both sexes, life expectancies in the wild were dramatically shorter than in the lab.

Evolutionary biologists have long sought to understand how environmental factors generate natural selection on the rate of aging, and ultimately influence the frequencies of genes that underpin genetic variation in this trait. Much less is known about how environment affects the expression of genes that modulate aging rate. Kawasaki et al. have shown that animals can age much faster in their stressful natural environments than in the benign conditions of the laboratory. Their results suggest that laboratory estimates of aging and lifespan (and, therefore, fitness) should be interpreted with considerable caution.


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Materials provided by University of Chicago Press Journals. Note: Content may be edited for style and length.


Journal Reference:

  1. Kawasaki et al. Environmental Effects on the Expression of Life Span and Aging: An Extreme Contrast between Wild and Captive Cohorts of Telostylinus angusticollis (Diptera: Neriidae).. The American Naturalist, 2008; 172 (3): 346 DOI: 10.1086/589519

Cite This Page:

University of Chicago Press Journals. "Old Before Their Time? Aging Rate In Flies Twice As Fast In Wild Than In Laboratory." ScienceDaily. ScienceDaily, 6 September 2008. <www.sciencedaily.com/releases/2008/09/080905153759.htm>.
University of Chicago Press Journals. (2008, September 6). Old Before Their Time? Aging Rate In Flies Twice As Fast In Wild Than In Laboratory. ScienceDaily. Retrieved March 28, 2024 from www.sciencedaily.com/releases/2008/09/080905153759.htm
University of Chicago Press Journals. "Old Before Their Time? Aging Rate In Flies Twice As Fast In Wild Than In Laboratory." ScienceDaily. www.sciencedaily.com/releases/2008/09/080905153759.htm (accessed March 28, 2024).

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