The extraordinary sex ratios in the splash pool copepod Tigriopus californicus

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dc.contributor.authorTai, Travis C.
dc.contributor.supervisorAnholt, Bradley Ralph
dc.date.accessioned2014-08-27T18:28:20Z
dc.date.available2015-08-16T11:22:05Z
dc.date.copyright2014en_US
dc.date.issued2014-08-27
dc.degree.departmentDepartment of Biology
dc.degree.levelMaster of Science M.Sc.en_US
dc.description.abstractFisher’s adaptive sex ratio theory predicts that organisms should invest equally in sons and daughters and the sex ratio at conception should be 1:1. Hamilton’s theory predicts that organisms should adjust sex ratios based on the relative strength of competition within a mating group. Testing sex ratio and sex allocation theories requires variation in sex ratio. Different sex allocation and sex allocation adjustment mechanisms can produce skewed sex ratios. I used Tigriopus californicus, a harpacticoid copepod with extrabinomial variation in sex ratios, to test sex ratio evolution and socially-mediated sex determination. Using artificially selected sex-biased populations, the trajectory of population sex ratios were as expected under Fisher’s theory and sex ratios approached/reached 0.5 proportion males. Populations with overlapping generations had a slower rate of change towards 0.5 than populations with non-overlapping generations. I show that these data are supported by multiple different models: a mechanistic and simulation model. I tested socially-mediated sex determination using seawater conditioned with different local sex ratios of copepods. There were detectable effects found in both wild populations and isofemale lines. However, these effects may be trivial as differences were small between treatments. Sex determination in T. californicus is a complex mechanism, with multiple genetic and environmental components. The complex nature of sex determination in T. californicus and the dynamic nature of their habitat in highly ephemeral splash pools provide a possible explanation for the non-Fisherian sex ratios we see.en_US
dc.description.scholarlevelGraduateen_US
dc.identifier.urihttp://hdl.handle.net/1828/5616
dc.language.isoenen_US
dc.rights.tempAvailable to the World Wide Weben_US
dc.rights.urihttp://creativecommons.org/publicdomain/zero/1.0/*
dc.subjectSex ratio evolutionen_US
dc.subjectFrequency dependent selectionen_US
dc.subjectTigriopus californicusen_US
dc.subjectFisheren_US
dc.subjectPolygenicen_US
dc.subjectSex determinationen_US
dc.subjectSocial mediationen_US
dc.subjectSex adjustmenten_US
dc.subjectOverlapping generationsen_US
dc.subjectSimulation modelen_US
dc.subjectExperimental evolutionen_US
dc.titleThe extraordinary sex ratios in the splash pool copepod Tigriopus californicusen_US
dc.typeThesisen_US

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