Sexual ornamentation and male reproductive strategies in the superb fairy-wren

My thesis investigates trade-offs associated with male sexual ornament expression in the superb fairy-wren, a cooperatively breeding songbird with extreme infidelity. In Chapter 1, I show experimentally that testosterone-treated males, which were forced to express more elaborate sexual ornaments, do not exhibit greater telomere shortening. In Chapter 2, I found that male sexual ornament expression traded-off with sperm quality, but showed no association with sperm quantity. In Chapter 3, I found that paternal care was predicted by the interaction between the risk of within-pair paternity loss and the promise of extra-pair paternity gain.