Home

About

Advanced Search

Browse by Discipline

Scientific Societies

E-print Alerts

Add E-prints

E-print Network
FAQHELPSITE MAPCONTACT US


  Advanced Search  

 
An empirical test of evolutionary theories for reproductive senescence and reproductive effort
 

Summary: An empirical test of evolutionary theories for
reproductive senescence and reproductive effort
in the garter snake Thamnophis elegans
Amanda M. Sparkman1
, Stevan J. Arnold2
and Anne M. Bronikowski1,*
1
Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011, USA
2
Department of Zoology, Oregon State University, Corvallis, OR 97331, USA
Evolutionary theory predicts that differential reproductive effort and rate of reproductive senescence will
evolve under different rates of external mortality. We examine the evolutionary divergence of age-specific
reproduction in two life-history ecotypes of the western terrestrial garter snake, Thamnophis elegans. We test
for the signature of reproductive senescence (decreasing fecundity with age) and increasing reproductive
effort with age (increasing reproductive productivity per gram female) in replicate populations of two life-
history ecotypes: snakes that grow fast, mature young and have shorter lifespans, and snakes that grow
slow, mature late and have long lives. The difference between life-history ecotypes is due to genetic
divergence in growth rate. We find (i) reproductive success (live litter mass) increases with age in both
ecotypes, but does so more rapidly in the fast-growth ecotype, (ii) reproductive failure increases with age in
both ecotypes, but the proportion of reproductive failure to total reproductive output remains invariant,

  

Source: Arnold, Stevan J. - Department of Zoology, Oregon State University

 

Collections: Biology and Medicine; Environmental Sciences and Ecology