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S N Austad

Publications and source records attributed to S N Austad.

4 recordsLinked to original sources
PubMed1991

Mammalian aging, metabolism, and ecology: evidence from the bats and marsupials.

This study compared trends in body size, life span, metabolic rate, and ecology of bats and marsupials with those from mammals generally, using a 580 species data base. The linear logarithmic relationship between mammalian body mass and maximum longevity, deleting bats and marsupials, is used as a standard against which to measure life spans of particular mammal groups. Bats have maximum life spans a minimum of 3 times those of nonflying eutherians--a trend resulting from neither low basal metabolic rate, the ability to enter torpor, nor large relative brain size. Marsupials live about 80% as long as nonflying eutherians despite averaging lower basal metabolic rates; similarly, there is no effect of heterothermy or relative brain size. These results directly conflict with predictions of both "rate of living" and brain-size mediated theories of aging. However, they are consistent with an evolutionary theory that posits exceptionally long life spans among mammals with reduced environmental vulnerability.

Aging↗
PubMed1989

Life extension by dietary restriction in the bowl and doily spider, Frontinella pyramitela.

Longevity of free-living female adult bowl and doily spiders was compared with that of captive spiders fed at dietary regimes of one, three, and five Drosophila melanogaster per week. Adult females lived, on average, only 8 days in the field and the pattern of survivorship showed no evidence that senescence contributed to mortality. In the laboratory, mean adult life span was 81.3, 63.9, and 42.3 days on the one, three, and five Drosophila diets, respectively. Decreased feeding rate also delayed egg laying and reduced total fecundity. Survival and reproductive patterns indicated the manifestation of spider senescence at all laboratory feeding levels, with a younger onset of senescence at the higher feeding rates.

Animals↗