Life history trade-offs are an organism\u27s balancing of energy allocations to necessary strategies of life: growth, reproduction, and survival. The success of a life history strategy depends on both the environment and the developmental constraints of an organism. The yeast Saccharomyces cerevisiae is an ideal organism to investigate microbial life history trade-offs. Since these yeast are found in a variety of environments with niche-specific strategies and the S. cerevisiae life cycle involves both sexual and asexual phases, I expected to see a life history trade-off between growth and reproduction within and between populations of yeast. A strain more efficient at mating should be a slower grower while a slow mater should proceed through the cell cycle quicker. To study this trade-off, I measured the relative rates of mating and asexual growth. I found a significant difference in both the speed of sexual and asexual reproduction within a single population as well as between populations from different environments. The results presented here are still preliminary, as the assays used to measure the relevant life history traits were prone to experimental error. Given that caveat, within the woodland population of yeast, which represents three distinct haplotypes, there appears to be an inverse relationship between the length of the cell cycle and the rate of mating, indicating a trade-off between the efficiency of each strategy. No pattern was found in strains of other ecotypes
