Using Life History Data to Compare the Evolutionary Strategies of European Urodles and Anurans, and to Assess the Relationship Between Fecundity and Body Mass

• Sara R. Stansbury

  Juniata College

  Author

In an effort to maintain evolutionary fitness, species utilize life history strategies which often involve tradeoffs. For instance, some species may produce more offspring than others, but these offspring may have a high rate of mortality. Fecundity differences between species may be explained by the pace-of-living syndrome hypothesis, which proposes that larger species typically have lower rates of metabolism and thus live longer lives than smaller organisms. To assess whether there is a relationship between body mass and the number of offspring produced, a scaling analysis was performed on data from 36 European amphibian species. Additionally, the quantity of offspring produced by 2 clades of amphibians with contrasting reproductive strategies (urodeles and anurans) was compared to investigate whether these different life history approaches result in tangible differences in fecundity. This research demonstrated a significant relationship between body mass and offspring produced in amphibians as a whole and the anuran clade, potentially due to the pace-of-living syndrome hypothesis and differences in resource acquisition; interestingly, this finding was not supported by urodele data. Further, anuran species tended to produce more offspring than urodele species of similar masses, possibly supporting the concept of a life history tradeoff. Through analysis of this data, researchers will progress in our understanding of the relationship between intrinsic factors and life history traits, thus furthering the world’s understanding of tactics necessary to maintain evolutionary fitness.

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