Bergmann’s rule describes the correlation between increased body size and living at higher latitudes, seen in many endothermic animals. However, there is debate over if Bergmann’s rule is applicable to ectotherms. Using an exhaustive review of the literature, we investigated whether the relationship between body size and latitude is consistent with Bergmann’s rule in >100 species of Alpheus snapping shrimps. We found a significant correlation between body size and latitude (i.e., latitudinal midpoint of the range), using both raw species correlations and correlations corrected for phylogeny (phylogenetic independent contrasts). We discuss multiple hypotheses that may explain adherence to Bergmann’s rule in this group of shrimp, and the broader ecological implications of variation in body size during a time of global change.

 The methionine salvage pathway (MSP) is a set of metabolic reactions that is highly conserved among species. The SPE3 gene of the budding yeast Saccharomyces cerevisiae, characterized as essential for growth, encodes spermidine synthase, which catalyzes the 3rd enzymatic step of the MSP and is involved in biosynthesis of spermidine. We investigated the effects of mutations in SPE3 and other genes of the MSP by comparing strains containing mutations in genes encoding for different MSP enzymes. Diploid heterozygotes were created via mating, and double mutants were created via knockout PCR, transformation, and recombination. Cell growth rate, viability, vacuolar morphology, and genetic relationships were analyzed via growth curves, viability tests, microscopy, and spot test assays. We found that SPE3 knockout haploid (spe3Δ) mutants are viable with a generation time unaffected by growth in minimal media. We also show that SPE3 mutations result in a hindered ability to respond to stressors. Characterization of these mutant strains and their responses to stressors will lead to better understanding of spermidine biosynthesis and the functions of the Spe3p enzyme and other MSP enzymes in S. cerevisiae.