Genetic variation in the primary sex ratio in populations of the intertidal copepod, Tigriopus californicus, is widespread on Vancouver Island

<b>Hypothesis</b>: Genetic variation for the primary sex ratio is widespread in a copepodwith polygenic sex determination. Cytoplasmic sex ratio distorters (e.g. Wolbachia andmicrosporidians) influence the primary sex ratio in this copepod. <br> <b>Organism</b>: The intertidal copepod, Tigriopus californicus; six populations from VancouverIsland, British Columbia. <br> <b>Study site</b>: Quantitative genetics experiment in the laboratory. PCR and antibioticsexperiment to test for the presence of cytoplasmic sex ratio distorters. <br> <b>Results</b>: Genetic variation for the primary sex ratio was found in five of the six populationssurveyed. The primary sex ratio was paternally transmitted. There was no evidence thatWolbachia or microsporidians influenced the primary sex ratio of T. californicus.