Immunocompetence of Leach's storm-petrels (Oceanodroma leucorhoa)
LE3 .A278 2012
2012
Shutler, Dave
Acadia University
Bachelor of Science
Honours
Biology
Growth and reproduction are energetically demanding life history events. When resources are limiting, trade-offs can occur in energy allocation. Long-lived species are hypothesized to prioritize immune function over energetically demanding traits, such as growth and reproduction. Leach’s storm-petrels are ideal for testing energetic trade-offs, because they are an abundant, long-lived species. Blood samples from 20 nestling and 26 adult Leach’s storm-petrels were collected to evaluate immunocompetence using a bacteria-killing assay. Duplicate Petri plates were prepared for each sample and the number of bacterial colonies that formed was counted. Colony counts were highly repeatable. Colony counts did not differ significantly between adults and chicks. For adults, no significant relationships were found between colony counts and morphological trait measurements (lowest P = 0.27). For chicks, when all growth measurements were included, no significant relationships were found between colony counts and growth rates of tarsi, bills, or wings (lowest P = 0.27). A significant relationship was observed between colony counts and mass growth rate (P = 0.02). When growth occurring after blood collection was excluded from analysis, significant positive correlations were observed between bacterial colony counts and growth rates of bills (P = 0.05) and mass (P = 0.006). No correlation was observed between colony counts of adults and their offspring. My results suggest that there is a “haves vs. have-nots” relationship between immunocompetence and mass growth rate. Negative correlations between growth rates and colony counts suggest individuals investing in high growth rate also invest in high immunocompetence. The absence of a difference in immunocompetence between chicks and adults is contrary to other published studies.
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https://scholar.acadiau.ca/islandora/object/theses:879
