{"id":{"repo_id":"uwo","oai_identifier":"oai:uwo.scholaris.ca:20.500.14721/34193"},"canonical_url":"https://search.dev.ndltd.org/etd/uwo/oai:uwo.scholaris.ca:20.500.14721/34193","repository":{"repo_id":"uwo","name":"Western University","base_url":"https://uwo.scholaris.ca/server/oai/request"},"display":{"title":"A test of the effects of androgens on immunity: no relationship between 11-keto testosterone and immune performance in bluegill sunfish (Lepomis macrochirus)","abstract":"The posited immunosuppressive effects of androgens are a key component of the immunocompetence handicap hypothesis (ICHH). My thesis uses bluegill sunfish (Lepomis macrochirus) to test two predictions arising from this hypothesis: (1) natural concentrations of the androgen 11-keto testosterone (11-KT) will be negatively related with immunity, and (2) an immunochallenge will lower 11-KT concentration. I found no evidence for a relationship between natural 11-KT concentration and measures of immunity (leukocyte counts, respiratory burst, cytokine gene expression), and an immunochallenge with Vibrio vaccine did not affect 11-KT concentration. I performed a meta-analysis of immunochallenge studies to help interpret my results, and report evidence suggesting that immunochallenges have weaker effects on androgens in fishes compared to other vertebrates. These results suggest that the ICHH may not apply to all vertebrates, though it remains premature to state which factors specific to fish may account for the weaker evidence in favour of immunosuppressive androgens.","abstract_html":"The posited immunosuppressive effects of androgens are a key component of the immunocompetence handicap hypothesis (ICHH). My thesis uses bluegill sunfish (Lepomis macrochirus) to test two predictions arising from this hypothesis: (1) natural concentrations of the androgen 11-keto testosterone (11-KT) will be negatively related with immunity, and (2) an immunochallenge will lower 11-KT concentration. I found no evidence for a relationship between natural 11-KT concentration and measures of immunity (leukocyte counts, respiratory burst, cytokine gene expression), and an immunochallenge with Vibrio vaccine did not affect 11-KT concentration. I performed a meta-analysis of immunochallenge studies to help interpret my results, and report evidence suggesting that immunochallenges have weaker effects on androgens in fishes compared to other vertebrates. These results suggest that the ICHH may not apply to all vertebrates, though it remains premature to state which factors specific to fish may account for the weaker evidence in favour of immunosuppressive androgens.","abstract_has_math":false,"creators":["Loggie, John W"],"institution":"The University of Western Ontario","degree_name":"M Sc","degree_level":null,"degree_discipline":"Biology","degree_department":null,"school":null,"contributors":[],"advisors":["Neff, Bryan D."],"committee_chairs":[],"committee_members":[],"year":2016,"date_issued":"2016-09-20","date_published":"2016-09-20","updated_at":"2026-07-27T21:56:11Z","subjects":["Immunocompetence handicap hypothesis","sexual selection","androgens","immunity","11-ketotestosterone","bluegill sunfish"],"languages":["en_ca"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/20.500.14721/34193","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Neff, Bryan D."]},{"key":"dc:creator","label":"Author","values":["Loggie, John W"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2025-07-10T20:00:44Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2025-07-10T20:00:44Z"]},{"key":"dc:date.issued","label":"Date","values":["2016-09-20"]},{"key":"dc:publisher","label":"Institution","values":["The University of Western Ontario"]},{"key":"dc:type","label":"Dc Type","values":["thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Biology"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M Sc"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Immunocompetence handicap hypothesis","sexual selection","androgens","immunity","11-ketotestosterone","bluegill sunfish"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en_ca"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/20.500.14721/34193"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The thesis cover page in the PDF document includes references to Western University’s previous institutional repository platform, known as Scholarship@Western, and links to that platform (beginning with ir.lib.uwo.ca). In citing or referring to this thesis, use the DOI or handle from this page instead. Sample citation: Author name, \"Thesis title.\" (Year). Western University Open Repository. https://doi.org/10.71858/123456."]},{"key":"dc:description.abstract","label":"Abstract","values":["The posited immunosuppressive effects of androgens are a key component of the immunocompetence handicap hypothesis (ICHH). My thesis uses bluegill sunfish (Lepomis macrochirus) to test two predictions arising from this hypothesis: (1) natural concentrations of the androgen 11-keto testosterone (11-KT) will be negatively related with immunity, and (2) an immunochallenge will lower 11-KT concentration. I found no evidence for a relationship between natural 11-KT concentration and measures of immunity (leukocyte counts, respiratory burst, cytokine gene expression), and an immunochallenge with Vibrio vaccine did not affect 11-KT concentration. I performed a meta-analysis of immunochallenge studies to help interpret my results, and report evidence suggesting that immunochallenges have weaker effects on androgens in fishes compared to other vertebrates. These results suggest that the ICHH may not apply to all vertebrates, though it remains premature to state which factors specific to fish may account for the weaker evidence in favour of immunosuppressive androgens."]},{"key":"dc:title","label":"Title","values":["A test of the effects of androgens on immunity: no relationship between 11-keto testosterone and immune performance in bluegill sunfish (Lepomis macrochirus)"]}]}],"canonical_facts":{"dc:contributor.advisor":["Neff, Bryan D."],"dc:creator":["Loggie, John W"],"dc:date.accessioned":["2025-07-10T20:00:44Z"],"dc:date.available":["2025-07-10T20:00:44Z"],"dc:date.issued":["2016-09-20"],"dc:description":["The thesis cover page in the PDF document includes references to Western University’s previous institutional repository platform, known as Scholarship@Western, and links to that platform (beginning with ir.lib.uwo.ca). In citing or referring to this thesis, use the DOI or handle from this page instead. Sample citation: Author name, \"Thesis title.\" (Year). Western University Open Repository. https://doi.org/10.71858/123456."],"dc:description.abstract":["The posited immunosuppressive effects of androgens are a key component of the immunocompetence handicap hypothesis (ICHH). My thesis uses bluegill sunfish (Lepomis macrochirus) to test two predictions arising from this hypothesis: (1) natural concentrations of the androgen 11-keto testosterone (11-KT) will be negatively related with immunity, and (2) an immunochallenge will lower 11-KT concentration. I found no evidence for a relationship between natural 11-KT concentration and measures of immunity (leukocyte counts, respiratory burst, cytokine gene expression), and an immunochallenge with Vibrio vaccine did not affect 11-KT concentration. I performed a meta-analysis of immunochallenge studies to help interpret my results, and report evidence suggesting that immunochallenges have weaker effects on androgens in fishes compared to other vertebrates. These results suggest that the ICHH may not apply to all vertebrates, though it remains premature to state which factors specific to fish may account for the weaker evidence in favour of immunosuppressive androgens."],"dc:identifier.uri":["https://hdl.handle.net/20.500.14721/34193"],"dc:language.iso":["en_ca"],"dc:publisher":["The University of Western Ontario"],"dc:subject":["Immunocompetence handicap hypothesis","sexual selection","androgens","immunity","11-ketotestosterone","bluegill sunfish"],"dc:title":["A test of the effects of androgens on immunity: no relationship between 11-keto testosterone and immune performance in bluegill sunfish (Lepomis macrochirus)"],"dc:type":["thesis"],"thesis:degree_discipline":["Biology"],"thesis:degree_name":["M Sc"]},"updated_at":"2026-07-27T21:56:11Z"}